First I asked them to play it from memory. Then, to compose something similar. Today comes what actually matters to me as a piano teacher: that they tell me how to study it. And here I have to retract a line I wrote in 2024.
The pedagogical lane
Third path of the Chopin-Cortot Benchmark, and the one that gives it its surname. Alfred Cortot published his celebrated Chopin éditions de travail: the score, and in front of every difficult passage, a text naming the difficulty and a battery of formulas to overcome it, built from the passage’s own notes. Dotted rhythms, displaced accents, held notes, stops, hands redistributed. It is not “repeat it slowly”: it is a way of thinking about study.
The test has two steps, in the same conversation. First I give them the complete Nocturne Op. 9 No. 2 written in LilyPond code, with no title, no composer and no clue whatsoever, and ask for the diagnosis:
Tell me about the technical and expressive difficulties that a piano student might encounter with this piece in Lilypond code. Indicate the measure and beat, when necessary, to be precise in your examples.
And afterwards, the exercises:
Now create different technical exercises in the style of Alfred Cortot (in lilypond code) to help with the most challenging technical aspects of the nocturne. Remember that these exercises should be directly related to the nocturne you have composed.
🔧 Two confessions about the prompts
The second sentence of the first prompt is an addition of mine from today. In 2024 the question was only the first sentence, the answers came out generic, and I had to press with a second prompt asking for bar and beat. This time I have asked for it up front. I mention it because it affects the comparison: part of 2026’s precision I have handed over on a plate.
The second prompt is the literal wording from 2024, slip-up included: it says “the nocturne you have composed” even though they haven’t composed anything. None of the three has complained.
As in the previous posts: a single attempt, reasoning at its highest “effort”, every tool available and everything logged.
Flashback: 2024
I did this very same thing back in October 2024 with Claude 3.5 and GPT-4o. Rereading it now is an archaeological exercise. About the diagnoses I wrote that they were “very generic”, valid for any nocturne, and that when I finally got specifics, the inventions arrived:
Now it is much more specific in details, and although it has some hallucinations, like the nonexistent polyrhythm of three against two in measure 2, in general, the instructions it provides have some correlation with what is written in the score.
“Some correlation with what is written in the score.” That was the bar. And about the exercises, first the joy of seeing that it knew who Cortot was, and then the reality:
To some extent, it is coherent in proposing exercises for the difficulties it had previously mentioned. However, these aren’t truly Cortot exercises; it simply asks for fragments to be repeated and provides general (though correct) study instructions.


Better not to even mention GPT-4o: its code came with, and I quote, “numerous errors that prevent correct visualization”. I compiled it again today in case time had healed it. About thirty errors. There is no image to show.
2025: the year of prose
In the October 2025 rerun, for a training course, Claude already did something different: it generated two documents on its own, one with the code and another with a study text that imitated Cortot’s tone right down to the prescriptions (“ten minutes a day for a week”). Eight exercises for the real piece. My note at the time was that there was “no significant progress in a year”, though there was “a certain improvement in the quality of the exercises proposed”.


Lots of prose and few formulas. It sounded like Cortot; it didn’t yet work like Cortot.
2026, first step: the diagnosis
All three answered without using any tool, just by reading the code. And two of them opened the same way, with a line that made me smile. Claude: “This is Chopin’s Nocturne in E♭ major, Op. 9 No. 2.” Gemini: “this score is a transcription of Frédéric Chopin’s Nocturne in E-flat major, Op. 9 No. 2.” No title, no composer, just notes in a text file. Astra never named it at all and worked with it as if it were an anonymous score. That, the question of recognition, will be another post.
The important thing: they are far more detailed and accurate than anything I had seen before. There is no longer any need to drag specifics out of them with a corkscrew, nor do I find phantom polyrhythms. I have been checking against the code claims that in 2024 would have been invented:
- Claude says that in bar 16 there are “thirteen notes against three left-hand eighth notes”, grouped 4 + 4 + (2 + triplet). I counted them: thirteen, grouped just like that.
- All three cite the four-against-three polyrhythm in bar 18 and the eight-against-three in bar 29. They exist, and they are where they say.
- Claude warns that “as encoded” the pedal goes down in bar 32 and is not released until bar 36, with the whole cadenza sitting over it. True: that is how it is in my file, and it noticed.
- Astra and Gemini discover the hidden tempo changes that MuseScore left inside the cadenza, and Astra warns that the student must shape it “rather than mechanically follow a succession of numerical tempo changes”.
- Claude starts by fixing how it is going to count: four dotted-quarter beats per bar, with the pickup as bar zero. It sounds trivial; it is what makes everything else checkable.
A slip or two remains: Gemini counts twelve thirty-second notes where there are ten and a triplet. Peccata minuta. In scope and depth, Claude (four and a half minutes of thinking) is clearly ahead; Astra (a minute and a half) is orderly and sensible; Gemini (one minute) is the most textbook-ish, but also correct. Here are the three complete texts, exactly as delivered:
📄 Claude Fable 5.1’s complete diagnosis
This is Chopin’s Nocturne in E♭ major, Op. 9 No. 2. I count four dotted-quarter beats per bar, so “m4, beat 2” means the second dotted quarter, with the eighth or sixteenth inside the beat given where needed. The pickup is measure 0. I worked only from reading the code and did not compile or play it.
The encoded tempo is ♩ = 60, which makes the eighth 120; Chopin’s marking is eighth = 132. The piece must be felt in 4, not in 12.
Left hand
-
Leaps on every beat. The bass–chord–chord pattern leaps a tenth or more on every beat. The largest leaps are twelfths:
- B♭1→F3 at m4 beat 2, and the same in m8, m16, m24 and m28.
- A♭1→E♭3 at m10 beat 2 and m18 beat 2.
- C2→G3 at m12 beat 1 and m20 beat 1.
- A♭1→E♭3 at m29–30 beat 1.
- All of this must stay pp and even, without the hand landing heavily after the jump.
-
Three dynamic layers in one hand.
- The bass notes form a line, for example the chromatic B♭2–B♮2–C3, then A2, in m3 beats 1–4.
- They need depth, the second eighth less, and the third eighth least.
- Students usually thump the top chord because it lies under the thumb.
-
Staccato basses in m1 (and m21–22).
- They occur under pedal, so they mean “release early to travel”, not a short sound.
-
Reading.
-
m2 beat 3 puts D♭ and E♮ in the same chord,
<bes des e>, above an F bass. -
m12 beats 3–4 abandon the pattern for chromatic chords spelled with D♯ and G♯ (
<bes d> <a dis> gis g). - The right hand sits only a step above them here (E4 against D♯4).
-
m2 beat 3 puts D♭ and E♮ in the same chord,
-
Memory traps from near-identical returns.
-
m1 and m5 beat 2 have
<ces d as'>, but m13 and m21 beat 2 have<bes d as'>. -
m4 and m8 beat 2 have
<bes as'>, but m16, m24 and m28 have<bes d as'>. -
m26 beat 3 adds a B♭ (
<g' bes es>) that m25 lacks.
-
m1 and m5 beat 2 have
-
m29–30 beats 1–2.
- The pattern changes to rising and falling inversions of A♭ minor, with no bass note on beat 2.
-
m32 beats 1–2.
-
Eight eighths are played in the time of six (
\times 6/8) while the right hand holds a long octave. - They form a B♭7 arpeggio from B♭1 to D5 with several position shifts.
- It must swell evenly to ff without bumps at the shifts.
-
Eight eighths are played in the time of six (
Pedal
-
m1 shows one pedal change per beat, then “Ped. simile”.
- This requires legato (syncopated) pedalling that catches each low bass after the hand has already left it.
-
Chromatic melody notes blur within one pedal:
- m6, m14 and m22, beats 1–2.
- m13 beats 1–2 (C♭–B♭–C♯–D).
- The runs in m16 beat 2 and m24 beats 1–2.
- The student needs half-changes or flutter pedal, judged by ear.
-
As encoded, the pedal goes down at m32 and is not released until m36.
- The cadenza cluster A–B♭–C♭–C sits over the held B♭7 harmony.
- It works in that register only if played very lightly.
Right hand: singing tone
-
Long notes that decay.
- G5 at m1 beat 1 is tied into beat 2, and m24 and m28 (beats 3–4) each hold a dotted half-note E♭5.
- The note after a long note (F at m1 beat 2) must match the decayed level, not the attack level.
-
The opening sixth B♭4→G5 (pickup to m1), fingered 2–5.
- It should sound like a vocal portamento, with no accent on the downbeat.
-
Expressive accents inside p.
- m5 beat 3, second eighth: a syncopated E♭ tied into beat 4.
- m9 beat 2: the accented G.
- These are agogic, leaning accents, not hits.
- The pp echo at m9 beat 3 needs a real colour change.
-
m10 beats 1–2: four repeated E♭5 with finger changes 3-2-1-3.
- They are portato under a slur, with poco rit.
- Each repetition needs a slightly different weight, with the key not fully released.
-
In m18 beat 1 the same notes become four against three (
\times 3/4), a true polyrhythm against the left-hand eighths.
-
Fingering.
- m11 beats 1–2 and m27 beat 1 put 4 on B♭5 and then 5 on A5.
- This looks like a Chopin-style black-to-white slide or crossing, but check it against a printed edition.
- Students raised on orthodox fingering find it awkward.
Leaps in the melody
-
Tenth, B♭4→D6.
- It falls on the first two eighths of beat 1 in m4, m8 and m16, under a slur.
- Moving in an arc with a soft landing avoids either a hole or an accent.
-
m24 beat 1 (
bes16 d'8).- The same leap is compressed into a sixteenth, with D6 arriving syncopated.
- This is the hardest version of the leap.
-
Octave leaps after turns.
- m2: C5 (turn, third eighth of beat 1) → C6 on beat 2.
- m26: E♭5 (turn, third eighth of beat 3) → E♭6 on beat 4.
- The turn must be unhurried and end on the thumb.
- I read the stacked fingering 1-4-3-2-1 in m2 as doing exactly that.
-
m27 beat 4.
- Grace E♭5 → G6, the highest melodic note, marked dolciss.
- It is followed by portato F–E♭–D–C.
- Landing softly after a tenth is the risk.
Ornaments
-
Short trills (
\prall) on sixteenths.- They occur at m5 beats 2 and 4, m13 beat 4 and m27 beat 3.
-
\trillon a sixteenth occurs at m21 beat 4 and m30 beat 1 (fifth sixteenth, in f). - They must be light and must not delay the next sixteenth.
-
Graces.
- Slide E–F before the staccato G at beat 2 of m7, m15 and m23.
- Acciaccatura A♭5 before the drop to C5 at m8 beat 2.
- Three-note arpeggio G4–B♭4–E♭5 into G5 with fp at m13 and m21 beat 1.
- Acciaccatura before the peak B♭5 at m22 beat 3.
- In Chopin tradition these start on the beat, with the bass.
- Students tend to play them early and lose coordination.
Fioriture and rhythm
-
m6, m14 and m22, beats 1–2.
- Twelve sixteenths in which the two-note slurs begin on weak sixteenths (D♭–C, F–E, A♭–G, D♭–C).
- The slur F–E straddles the boundary between beats 1 and 2.
- The phrasing contradicts the metre.
- The hand shifts for each pair (finger 3 on each appoggiatura).
- A drop G5→B4 opens the figure, and the crescendo aims at B♭5 on beat 3, played with finger 4.
-
m13 and m21, beats 1–2.
-
Accents on C♭5 at the start of beat 2 and on the dotted G5 (
g16. f32). - The enharmonic spelling is C♭–B♭–C♯–D.
-
Accents on C♭5 at the start of beat 2 and on the dotted G5 (
-
m16 beat 2.
- Thirteen notes against three left-hand eighths.
- They align as 4 + 4 + (2 + triplet).
- An accent falls off the beat, on C♭5, the last thirty-second of the second eighth.
-
m24 beat 2.
- Mixed subdivisions: sixteenths, a thirty-second triplet, two thirty-seconds, another triplet.
- A staccatissimo A♭5 is followed by a drop of a major seventh to A4.
-
m26 beat 2 and m29 beat 2.
- A written-out trill E♭–F, first six sixteenths, then eight in the time of six (eight against three).
- It should sound like a trill gaining speed, not like arithmetic.
-
m28 beat 2.
-
Repeated-note “sighs” (
beses16( as16) as16( g16) g16.( f32)). - The reading includes B𝄫, which is A♮ on the keyboard, and the fingering repeats 3.
-
Repeated-note “sighs” (
B section, m11–12 and m19–20
- The sixths and thirds in m11 beats 3–4 need the top voice projected.
- m12 beat 2 is portato with a repeated inner A.
-
m12 beats 3–4 are legato chords with chromatic inner motion.
- They carry F♯, B♮ and E♮ in E♭ major, with a crescendo and poco rallent.
-
Four tempo instructions fall within four bars:
- poco rit. in m10.
- a tempo at forte in m11.
- poco rallent. from m12 beat 3.
- a tempo with fp in m13.
- Students exaggerate each one and lose the thread.
Coda and cadenza
-
m30.
- A sudden con forza: the A♭ minor arpeggio A♭4→E♭6 in beat 2 with a thumb shift, then a thirty-second rest as a breath before F6–G6.
- The octave E♭6/7 enters syncopated on the third eighth of beat 3.
-
m31–32.
- Stretto octaves with C♭ and B𝄫 spellings.
- Black and white keys alternate, which favours 4–5 on top.
- The leaps run E♭5/6 → E♭6/7 (syncopated, m31 beat 3, second eighth) → F5/6 → C6/7.
- m32 is the only ff in the piece.
- Sound in that register turns harsh if forced, and the earlier f passages (m11, m19) must be kept below it.
-
m33–34.
- The four-note cell C♭7–B♭6–C7–A6 (fingered 3-2-4-1) is played twelve times.
- It accelerates and crescendos, then diminishes from the fifth group of m34.
- The challenges are evenness and a gradual, unstepped acceleration.
-
m35.
- The descent ends A♭5–C5–D5 → E♭5 at m36.
- That is the theme’s own cadence figure from m4 beat 2.
- It should be phrased as a recollection during smorz.
-
m36–37.
- The right hand takes a rocking accompaniment at pp, a double note plus single notes under one long slur.
- The left hand leaps E♭2→B♭3.
- The final ppp chords must sound complete and together, which is a classic control problem.
Overall expressive challenges
- Rubato. The left hand keeps the pulse while the right hand floats. The fioriture in m16, m24 and m29 should arrive on time at beat 3.
- Variation. m4, m8, m16 and m24 form a series of growing elaborations (legato, portato, chromatic, syncopated), and m5, m13 and m21 form another. Each should feel improvised yet graded across the piece.
- Dynamic architecture. The range from pp (m9, m26) to the single ff (m32) must be planned, with the tone kept dolce throughout.
📄 GPT-6 Astra’s complete diagnosis
The main difficulty is making the piece sound like a continuous, expressive melody while managing increasingly elaborate decoration, wide left-hand jumps, and changing rhythmic demands. The quieter passages require as much control as the brilliant ones.
Measure numbers below follow the code: the opening B♭ is an unnumbered pickup. In the 12/8 measures, “beat” means a dotted quarter, giving four beats per bar.
- Maintaining the compound pulse without making the accompaniment heavy. The left hand generally plays a bass note followed by two chords on each beat, as in mm. 1–8. A student may accent every bass landing or hesitate during the jump to the chords, making the music sound laboured. The challenge is to maintain flowing groups of three eighth notes while allowing the right hand to phrase independently.
In m. 1, the right-hand G continues across the boundary between beats 1 and 2. The student must feel the new beat in the accompaniment without rearticulating or artificially stressing the sustained melody.
- Navigating large left-hand leaps quietly and accurately. Particularly exposed jumps occur in m. 4, beat 2, from the low B♭ to the upper chord, and m. 29, beat 1, from the low A♭ into the chordal register. Similar movements recur throughout the piece.
These require quick lateral movement and preparation of the chord shape, rather than trying to hold the hand stretched between registers. Practising the bass and first chord of each group alone can help establish reliable distances. The expressive difficulty is landing securely without making the accompaniment louder than the melody.
- Sustaining a singing tone and controlling the balance between hands. The opening p, espressivo dolce asks for a clear melodic line over a relatively rich accompaniment. Long right-hand notes can be obscured by the repeated left-hand chords, particularly in mm. 1–3 and m. 25, beats 3–4.
In mm. 11–12 and 19–20, the melody becomes partly chordal. The upper notes must remain audible as the continuation of the tune; playing both notes of every interval with equal weight would thicken the texture. The move from p to pp in m. 9, beat 3 also requires a real change of colour without losing projection.
- Fitting ornaments into the phrase without disrupting its timing. The turn on C in m. 2, the third eighth of beat 1, needs to lead naturally into the high C on beat 2. The turn in m. 26, the last eighth of beat 3, similarly precedes an octave ascent at beat 4.
The short ornaments in m. 5, beats 2 and 4, and the grace notes before beat 2 of mm. 7, 15 and 23, demand light fingers and careful timing. A student may rush the following note, accent the ornament excessively, or lose the accompaniment’s pulse. The three grace notes introducing mm. 13 and 21 must also lead convincingly into the marked fp arrival. The code does not fully determine the expressive timing of these ornaments.
- Playing chromatic passagework evenly while preserving its melodic direction. Mm. 6, 14 and 22, beats 1–2, combine chromatic neighbours, changes of hand position, and short slurs. The challenge is more than accurate accidentals: each little gesture must belong to the larger rise and release of the phrase. Thumb movements and shifts between black and white keys can easily produce unwanted accents.
The difficulty increases in m. 16, beat 2, with its descending thirty-second notes and concluding triplet, and in m. 24, beats 1–2, where chromatic descent leads into a rapid figure containing two triplets. These passages benefit from practice in small destination-based groups, then reintegration into the underlying beat.
-
Coordinating irregular subdivisions with the accompaniment.
Several passages require distinct rhythmic solutions:
- M. 18, beat 1: four right-hand notes occupy the time of three left-hand eighth notes—a 4:3 relationship.
- M. 29, beat 2: eight right-hand sixteenths are compressed into one dotted-quarter beat, against three left-hand eighth notes.
- M. 32, beats 1–2: the left-hand eight-note tuplet spans two dotted-quarter beats beneath sustained right-hand octaves.
Students may distort these into familiar rhythms or rush their endings. Establishing the beginning, midpoint where useful, and arrival of each group helps maintain proportion without making the performance sound calculated.
- Distinguishing articulation from accent and dynamic weight. The detached descent in m. 8, from the final eighth of beat 1 through much of beat 2, needs lightness without becoming abrupt. The repeated E♭s in m. 10, beat 1, must remain individually articulated within the phrase and its poco ritardando.
Conversely, the accented E♭ in m. 5, beat 3, begins on the second eighth of the beat and continues into beat 4. Its expressive emphasis should not displace the metre. In mm. 13 and 21, beat 2, the accents within the chromatic decoration likewise need shaping rather than uniformly forceful attacks.
- Managing the octave climax without tension. The octave writing beginning in m. 30, on the last eighth of beat 3, and continuing through mm. 31–32, introduces a substantial change of technique. The student must negotiate register changes, black-key octaves and larger leaps while keeping the wrist mobile.
In m. 31, the leap from the lower E♭ octave on beat 3 to the higher E♭ octave on its second eighth is especially exposed. The stretto, accents and eventual ff can encourage tightening or uncontrolled acceleration. The climax needs a planned increase in intensity, with enough physical release between attacks.
- Using pedal to support resonance while keeping harmony and articulation clear. M. 1 establishes pedal changes on each dotted-quarter beat, followed by Ped. simile in m. 2. Coordinating these changes with the bass jumps is demanding: releasing too early can leave gaps, while changing too late can mix harmonies.
Chromatic passages, especially mm. 12 and 20, beats 3–4, need attentive listening and potentially lighter or more frequent changes. Pedal must also preserve the audible distinction between detached and sustained playing. The pedal held from m. 32 creates a different challenge: managing the accumulated resonance through the cadenza.
- Shaping freedom, return and final withdrawal. The slowing in mm. 10, 12 and 20 must lead to convincing a tempo returns in mm. 11, 13 and 21. Likewise, poco rubato in m. 26 should enrich the melodic line without making the accompaniment unstable.
Mm. 33–35 form a distinct expressive problem: Senza tempo, repeated thirty-second-note patterns, acceleration, and then rallentando, smorzando. The student must shape these as a coherent flourish rather than mechanically follow a succession of numerical tempo changes. The silent spacers in mm. 33–34 should not automatically be interpreted as literal pauses.
Finally, m. 36 restores the accompaniment at pp, and m. 37 withdraws to ppp. Quiet chord attacks and register changes must remain secure, allowing the ending to sound settled and resonant rather than merely faint.
📄 Gemini 3.1 Pro’s complete diagnosis
Based on the LilyPond code provided, this score is a transcription of Frédéric Chopin’s Nocturne in E-flat major, Op. 9 No. 2. This is a staple of the Romantic piano repertoire and presents several distinct technical and expressive challenges for a student.
Here is a breakdown of the primary difficulties a piano student would encounter when studying this piece, with references to specific measures and beats:
Technical Difficulties
1. Left-Hand Jumps and Accuracy
- The Challenge: The piece relies on a “stride” or waltz-like accompaniment adapted for a 12/8 meter (Bass note – Chord – Chord). The left hand must constantly leap from low root notes in the bass to middle-register chords, requiring great spatial awareness and a relaxed arm.
-
Examples:
-
Measure 1: The left hand jumps from a low E-flat (
es,,8) to a mid-range E-flat major chord (<g' es'>8 <bes es g>8). -
Measure 2: The code indicates
Ped. simile, meaning this leaping pattern continues throughout the piece.
-
Measure 1: The left hand jumps from a low E-flat (
2. Intricate Ornamentation
- The Challenge: Chopin’s writing requires ornaments to sound effortless, vocal, and completely integrated into the melodic line rather than rhythmically jarring.
-
Examples:
-
Measure 2, Beat 1: A turn (
\turn) on the C eighth note. The fingering provided (-1 -4 -3 -2 -1) requires significant finger independence to execute smoothly while keeping the wrist relaxed. -
Measure 5, Beats 2 & 4: Trills/mordents (
\prall) embedded within sixteenth-note runs. -
Measure 21, Beat 4: A trill (
\trill) that must resolve elegantly into the next phrase.
-
Measure 2, Beat 1: A turn (
3. Rhythmic Groupings and Fiorituras (Right Hand)
- The Challenge: The student must fit fast, unmeasured scale runs and delicate rhythmic groupings into a steady left-hand pulse.
-
Examples:
-
Measure 16, Beat 2: A very rapid, complex run. The LilyPond code crams 12 thirty-second notes into a single dotted-quarter beat (
c32 b bes a as f d ces bes d \times 2/3 { g f es }). -
Measure 33-35: The famous Senza tempo cadenza. Written entirely as thirty-second notes (
ces32 bes c a...), this long, alternating figure requires perfect physical evenness and lightness of touch. (The hidden MIDI tempo markings in your code—ranging from\tempo 4=35to\tempo 4=80and back down—illustrate the kind of rhythmic pacing and acceleration/deceleration required).
-
Measure 16, Beat 2: A very rapid, complex run. The LilyPond code crams 12 thirty-second notes into a single dotted-quarter beat (
4. Double Notes and Octaves
- The Challenge: Playing multiple voices or large intervals in the right hand while maintaining a singing tone and perfect legato.
-
Examples:
-
Measure 12: A descending sequence of right-hand double notes and chords (
<g es'>4. <a d>8 <a c>...), which forces the student to carefully connect the top notes. -
Measures 30–31: The climax of the piece (con forza into stretto). The right hand must play bold, accurate octaves (
<es es'>4 <d d'>8 <c c'>8) without tensing up.
-
Measure 12: A descending sequence of right-hand double notes and chords (
Expressive Difficulties
1. Bel Canto Tone and Voicing
- The Challenge: The piece is heavily inspired by Italian opera. The right hand must sing (cantabile) with a beautiful, carrying tone that projects over the dense left-hand accompaniment.
-
Examples:
-
Measure 1: Marked espress. dolce. The student must balance the hands so the right-hand melody (
bes8 g'4.) floats above the accompaniment. - Measure 27: Marked dolciss. (dolcissimo). The student must achieve an incredibly soft, sweet tone in the high register.
-
Measure 1: Marked espress. dolce. The student must balance the hands so the right-hand melody (
2. Rubato and Pacing
- The Challenge: Chopin’s music demands tempo rubato—the subtle bending of time for expressive effect. The left hand must act as a steady conductor while the right hand takes liberties, which is conceptually and physically difficult for students.
-
Examples:
- The score is filled with explicit timing changes: poco rallent. (Measures 12, 20), a tempo (Measures 11, 13, 21), poco rubato (Measure 26), and stretto (Measure 30).
- Measure 35: Marked rallent. smorz. (slowing down and dying away), requiring the student to let the cadenza naturally run out of breath before the final a tempo (Measure 36).
3. Dynamic Control and Contrast
- The Challenge: Controlling a massive dynamic range on the piano without producing a harsh tone at loud volumes or “ghosting” (failing to sound the keys) at soft volumes.
-
Examples:
- Sudden accents: The fp (forte-piano) markings in Measure 13, Beat 1 and Measure 21, Beat 1, paired with an a tempo mark, require an immediate and surprising drop in volume.
- Extremes: The piece ranges from a massive ff arpeggiated chord in the left hand (Measure 32) to an incredibly delicate ppp final chord (Measure 37).
4. Pedaling
- The Challenge: Using the sustain pedal to connect the leaping bass notes to their corresponding chords without blurring the changing harmonies or muddying the right-hand melody.
-
Examples: Measures 1–2 explicitly notate
\sustainOnand\sustainOff, followed by Ped. simile. The student must learn syncopated (or “legato”) pedaling, changing the pedal exactly as the new bass note is struck on beats 1 and 3 of every measure.
2026, second step: the exercises
Claude Fable 5.1: fourteen exercises and six pages
This is where I sat staring at the screen for a while. Claude handed in fourteen exercises over six pages, and the first thing that strikes you is that they have the form of Cortot: a title naming the passage, a short text naming the difficulty and saying how to work on it, and below, the lettered formulas, a), b), c), built from the passage’s real notes. For the left-hand leaps it opens with a line any teacher would sign, “the difficulty is not the chord but the journey”, and works it outward, on the return, and exaggerated; the bass split between the two hands to hear the ideal balance before looking for it with one alone; the thumb alone on the stretto octaves and then the fourth and fifth fingers alone; the polyrhythms built through successive doublings, 2:3, 4:3, 8:3, with a composite rhythm line underneath. And even a syncopated pedal exercise with bracket notation showing the exact instant of the change.
They are very well described, written in an unmistakably technical-exercise format, and very close to what Cortot actually proposes. It also has the honesty to flag what is its own: it notes which fingerings it added because the score did not carry them, and which extensions are “my extensions in Cortot’s manner, not Chopin’s text”.






🔧 How it did it
Six minutes and fourteen tool calls. It checked that LilyPond was installed, wrote the file, compiled it, opened the rendered pages to look at them, corrected, compiled again and looked again, three times over. At the end it even admits that it tried to delete the temporary images and the system would not let it.
📄 Claude Fable 5.1’s complete answer
I’ve written fourteen Cortot-style preparatory exercises for the nocturne as LilyPond code. The file compiles with no warnings under LilyPond 2.26 (the \version header is 2.24.4), and I checked the rendered pages.
Each exercise follows Cortot’s layout: a short text naming the difficulty and how to work on it, then lettered formulas built from the actual notes of the passage. The formulas use his usual devices: isolating the gesture, dotted rhythms in both directions, stops, displaced accents, held notes, redistribution between the hands and chromatic transposition. Measure and beat references match the ones in my analysis.
| # | Difficulty addressed | Source passage | Formulas |
|---|---|---|---|
| 1 | Left-hand leap from bass to chord | The tenth in m1 beat 1 and the twelfths in m4 beat 2, m10 beat 2, m12 beat 1 | a) fast outward leap; b) fast return; c) leap exaggerated straight to the second chord; d) m4 with each bass delayed a sixteenth |
| 2 | Three dynamic layers in the left hand | m3 (bass line B♭–B♮–C–A) | a) part split between the hands to hear the ideal balance; b) thumb repeated ppp over held chord notes |
| 3 | Slurred leap of a tenth, B♭4→D6 | m4, m8, m16, beat 1; m24 | a) through the intermediate octave; b) there and back; c) a semitone lower and higher; d) the syncopated m24 version |
| 4 | Turn followed by an octave leap | m2 beat 1; m26 beat 3 | a), c) slow with equal notes, ending on the thumb; b), d) real rhythm as a quintuplet within the eighth |
| 5 | Appoggiatura pairs against the metre | m6, m14, m22, beats 1–2 | a) pairs alone with the hand shifts (3-2, 3-2, 3-2, 4-3); b) pairs accented; c) both dotted rhythms |
| 6 | Short trills on a sixteenth | m5 beats 2 and 4; m13, m21, m27, m30 | a) three-note trill with fingerings 3-4-3, 2-3-2, 1-3-2; b) the m5 figure written out as a descending sequence |
| 7 | Thirteen-note fioritura | m16 beat 2 (variant in m24) | a) slow and even; b), c) dotted rhythms; d) the two crossings isolated (3-1-4 on B♭–A–A♭, 2 over 1 on C♭–B♭); e) groups at speed with stops |
| 8 | Polyrhythms | m18 beat 1 (4:3); m29 beat 2 (8:3) | successive doublings 2:3, 4:3, 8:3 over the real left hand, with a rhythm line showing the composite rhythm |
| 9 | Repeated note with finger change | m10 beats 1–2 | a) 4-3-2-1 substitutions on scale degrees; b) the passage with 3-2-1-3 |
| 10 | Legato chords with chromatic inner parts | m12 and m20, beats 3–4 | a) top voice legato, lower parts staccato; b) the reverse; c) both hands into the fp of m13 |
| 11 | Arpeggio con forza | m30 beats 1–2 | a) thumb passage G–A♭–C♭; b) dotted rhythms and a stop on the top note; c) as written |
| 12 | Stretto octaves | m30–32 | a) thumb alone; b) fingers 4 and 5 alone; c) dotted rhythm; d) the leaps of m31 beats 3–4 |
| 13 | Cadenza cell C♭–B♭–C–A (3-2-4-1) | m33–35 | a) accent displaced onto each note; b) dotted rhythms; c) thumb held down; d) written-out accelerando from eighths to thirty-seconds |
| 14 | Syncopated pedal | m1 and the start of m2 | bracket pedal notation with tied sixteenths showing the exact instant of each change |
Where the score gives no fingering I added my own: the left-hand fingering in Ex. 1, the turn in Ex. 4c/d, Ex. 9a, the cadenza thumb, and the upper-finger octave fingering in Ex. 12b. The scalewise sequence in Ex. 6b beyond its first two beats, and the semitone transpositions in Ex. 3c, are my extensions in Cortot’s manner, not Chopin’s text.
Files are in the working directory:
-
cortot-exercises-nocturne.ly -
cortot-exercises-nocturne.pdf -
cortot-exercises-nocturne-page1.pngtocortot-exercises-nocturne-page6.png
The rm cleanup step was blocked by the permission prompt, so the PNG previews are still in the directory. To recompile, run lilypond cortot-exercises-nocturne.ly.
🔧 The code for the fourteen exercises
\version "2.24.4"
\pointAndClickOff
%% ------------------------------------------------------------------
%% Preparatory exercises, in the manner of Alfred Cortot's
%% "editions de travail", for the Nocturne in E-flat major
%% (12/8, Andante) analysed previously.
%% Every exercise is built from the actual notes of the passage
%% named in its title (measure / beat numbers refer to that score).
%% ------------------------------------------------------------------
\header {
title = "Nocturne in E-flat major"
subtitle = "Preparatory exercises in the manner of A. Cortot"
tagline = ##f
}
\paper {
indent = 0
ragged-right = ##f
markup-system-spacing.padding = #3
score-markup-spacing.padding = #4
system-system-spacing.padding = #3
}
\layout {
\context {
\Score
\omit BarNumber
}
}
exTitle =
#(define-markup-command (exTitle layout props text) (markup?)
(interpret-markup layout props
(markup #:vspace 0.6 #:bold #:larger text)))
%% ==================================================================
%% 1. LEFT HAND: THE LEAP FROM THE BASS TO THE CHORD
%% ==================================================================
\markup \exTitle "1. Left hand: the leap from the bass to the chords (mm. 1, 4, 10, 12)"
\markup \justify {
The difficulty is not the chord but the journey. The hand must travel
close to the keys, in one curved gesture, and be over the chord before
it is needed. Work on the four widest leaps of the piece: a tenth
(m. 1, beat 1) and the three twelfths (m. 4 beat 2, m. 10 beat 2,
m. 12 beat 1). Repeat each bar four to eight times, pianissimo, first
looking at the keyboard, then with the eyes closed.
Formula a) trains the outward journey, b) the return to the bass,
c) exaggerates the distance by leaping directly to the second chord,
so that the real leap then feels small.
}
\score {
\new Staff {
\clef bass \key es \major \time 2/4
\mark \markup \small "a)"
\repeat volta 2 { es,16-5 <g es'>8.-2-1 es,16 <g es'>8. }
\repeat volta 2 { bes,,16 <f d'>8. bes,,16 <f d'>8. }
\repeat volta 2 { as,,16 <es ces'>8. as,,16 <es ces'>8. }
\repeat volta 2 { c,16 <g es'>8. c,16 <g es'>8. }
\break
\mark \markup \small "b)"
\repeat volta 2 { es,8. <g es'>16 es,8. <g es'>16 }
\repeat volta 2 { bes,,8. <f d'>16 bes,,8. <f d'>16 }
\repeat volta 2 { as,,8. <es ces'>16 as,,8. <es ces'>16 }
\repeat volta 2 { c,8. <g es'>16 c,8. <g es'>16 }
\break
\mark \markup \small "c)"
\repeat volta 2 { es,8 <bes es' g'> es, <bes es' g'> }
\repeat volta 2 { bes,,8 <bes as'> bes,, <bes as'> }
\repeat volta 2 { as,,8 <as ces' es'> as,, <as ces' es'> }
\repeat volta 2 { c,8 <c' es' g'> c, <c' es' g'> }
}
\layout { }
}
\markup \justify {
d) Measure 4 as written, but each bass delayed by a sixteenth: the time
allowed for the displacement is halved, while the chords keep their place.
}
\score {
\new Staff {
\clef bass \key es \major \time 12/8
\repeat volta 2 {
r16 bes,16 <f es'>8 <bes es' as'>8
r16 bes,,16 <f d'>8 <bes as'>8
r16 es,16 <g es'>8 <bes es' g'>8
r16 es16 <g es'>8 <bes es' g'>8
}
}
\layout { ragged-right = ##t }
}
%% ==================================================================
%% 2. LEFT HAND: THREE PLANES OF SONORITY
%% ==================================================================
\markup \exTitle "2. Left hand: three planes of sonority (m. 3)"
\markup \justify {
The bass notes form a melodic line (B-flat, B-natural, C, A in m. 3);
the two chords are only a halo, the second lighter than the first.
a) Divide the part between the two hands in order to hear the ideal
balance: the left hand sings the basses, the right hand breathes the
chords. Then play the measure as written with the left hand alone and
try to reproduce exactly the same sonority.
b) The thumb is the natural enemy of this accompaniment. Hold the lower
notes of each chord silently sunk in the keys and repeat the thumb note
as lightly as possible, the key never rising completely.
}
\score {
\new PianoStaff <<
\new Staff {
\clef bass \key es \major \time 12/8
\mark \markup \small "a)"
r8^\markup \italic "m.d. pp" <f d'>8-. <bes d' as'>-.
r8 <g f'>-. <d' f' g'>-.
r8 <g es'>-. <c' es' g'>-.
r8 <ges es'>-. <c' es' ges'>-. \bar "||"
}
\new Staff {
\clef bass \key es \major \time 12/8
bes,4.--_\markup \italic "m.s. cantando" b,4.-- c4.-- a,4.--
}
>>
\layout { ragged-right = ##t }
}
\score {
\new Staff {
\clef bass \key es \major \time 12/8
\mark \markup \small "b)"
\repeat volta 2 {
<< { g'8-.-1^\markup \italic "ppp" g'-. g'-. as'-. as'-. as'-. }
\\ { <bes es'>4. <ces' d'>4. } >>
<< { as'8-. as'-. as'-. g'-. g'-. g'-. }
\\ { <bes d'>4. <c' es'>4. } >>
}
}
\layout { ragged-right = ##t }
}
%% ==================================================================
%% 3. RIGHT HAND: THE SLURRED LEAP OF A TENTH
%% ==================================================================
\markup \exTitle "3. Right hand: the slurred leap of a tenth (mm. 4, 8, 16, 24, beat 1)"
\markup \justify {
The upper note must be reached by a lateral sliding of the hand, never
thrown from above, so that the D arrives without accent.
a) Measure the distance through the intermediate octave.
b) The leap itself, there and back.
c) The same, a semitone lower and a semitone higher: the true interval
will seem easy afterwards.
d) The compressed and syncopated version of m. 24.
}
\score {
\new Staff {
\clef treble \key es \major \time 2/4
\mark \markup \small "a)"
\repeat volta 2 { bes'16-2( bes''-5 d'''8-5) bes'16( bes'' d'''8) }
\mark \markup \small "b)"
\repeat volta 2 { bes'8-2( d'''-5) bes'( d''') }
\break
\mark \markup \small "c)"
\repeat volta 2 { a'8-2( cis'''-5) a'( cis''') }
\repeat volta 2 { b'8-2( dis'''-5) b'( dis''') }
\mark \markup \small "d)"
\repeat volta 2 { bes'16-2( d'''8-5 cis'''16-4) bes'16( d'''8 cis'''16) }
}
\layout { }
}
%% ==================================================================
%% 4. TURN FOLLOWED BY AN OCTAVE LEAP
%% ==================================================================
\markup \exTitle "4. The turn followed by an octave leap (m. 2 beat 1; m. 26 beat 3)"
\markup \justify {
The turn must finish on the thumb, which then serves as a pivot for the
octave. a) and c) slowly, with equal notes; b) and d) in the real rhythm,
the five notes filling exactly the last eighth of the beat.
Transpose afterwards chromatically, keeping the same fingering.
}
\score {
\new Staff {
\clef treble \key es \major \time 2/4
\mark \markup \small "a)"
\repeat volta 2 { c''16-1( d''-4 c''-3 b'-2 c''8-1 c'''-5) }
\time 3/8
\mark \markup \small "b)"
\repeat volta 2 { \tuplet 5/4 { c''32-1( d''-4 c''-3 b'-2 c''-1 } c'''4-5) }
\break
\time 2/4
\mark \markup \small "c)"
\repeat volta 2 { es''16-2( f''-4 es''-3 d''-2 es''8-1 es'''-5) }
\time 3/8
\mark \markup \small "d)"
\repeat volta 2 { \tuplet 5/4 { es''32-2( f''-4 es''-3 d''-2 es''-1 } es'''4-5) }
}
\layout { }
}
%% ==================================================================
%% 5. APPOGGIATURA PAIRS AGAINST THE METRE
%% ==================================================================
\markup \exTitle "5. The pairs of appoggiaturas against the metre (mm. 6, 14, 22, beats 1 - 2)"
\markup \justify {
Each slurred pair begins on a weak sixteenth and demands a new position
of the hand: drop the wrist on the appoggiatura, lift it on the
resolution.
a) The pairs alone, ascending and descending.
b) The passage with the pairs deliberately accented.
c) The passage in dotted rhythm, without pedal, for the equality of
the fingers. Finally play as written: the pairs remain audible as
inflexions, but the accents disappear into the crescendo towards the
B-flat of beat 3.
}
\score {
\new Staff {
\clef treble \key es \major \time 2/4
\mark \markup \small "a)"
\repeat volta 2 {
des''16-3( c''-2) f''-3( e''-2) as''-3( g''-2) des'''-4( c'''-3)
as''16-3( g''-2) f''-3( e''-2) des''-3( c''-2) r8
}
}
\layout { ragged-right = ##t }
}
\score {
\new Staff {
\clef treble \key es \major \time 6/8
\mark \markup \small "b)"
\repeat volta 2 {
g''16 b' c'' des''->( c'') f''->( e'') as''->( g'') des'''->( c''' g''
bes''4.) r4.
}
\break
\mark \markup \small "c)"
\repeat volta 2 {
g''16. b'32 c''16. des''32 c''16. f''32 e''16. as''32 g''16. des'''32 c'''16. g''32
bes''4. r4.
}
\repeat volta 2 {
g''32 b'16. c''32 des''16. c''32 f''16. e''32 as''16. g''32 des'''16. c'''32 g''16.
bes''4. r4.
}
}
\layout { }
}
%% ==================================================================
%% 6. SHORT TRILLS ON A SIXTEENTH
%% ==================================================================
\markup \exTitle "6. The short trill on a sixteenth (m. 5 beats 2 and 4; mm. 13, 21, 27, 30)"
\markup \justify {
The ornament must take nothing from the following note.
a) The three notes of the trill alone, with the fingerings 3 4 3,
then 2 3 2, then 1 3 2; the long note is a rest for the hand.
b) The figure of m. 5 written out and continued as a descending
sequence (the first two beats are those of Chopin). Practise it with
each of the three fingerings, the left hand playing plain eighths on
any chord in order to control the regularity.
}
\score {
\new Staff {
\clef treble \key es \major \time 2/4
\mark \markup \small "a)"
\repeat volta 2 { f''32-3 g''-4 f''8.-3 f''32 g'' f''8. }
\repeat volta 2 { f''32-2 g''-3 f''8.-2 f''32 g'' f''8. }
\repeat volta 2 { f''32-1 g''-3 f''8.-2 f''32 g'' f''8. }
}
\layout { ragged-right = ##t }
}
\score {
\new Staff {
\clef treble \key es \major \time 12/8
\mark \markup \small "b)"
\repeat volta 2 {
f''16 g'' \tuplet 3/2 { f''32-3 g''-4 f''-3 } e''16-2 f'' g''
es''16 f'' \tuplet 3/2 { es''32 f'' es'' } d''16 es'' f''
d''16 es'' \tuplet 3/2 { d''32 es'' d'' } cis''16 d'' es''
c''16 d'' \tuplet 3/2 { c''32 d'' c'' } b'16 c'' d''
}
}
\layout { }
}
%% ==================================================================
%% 7. THE CHROMATIC FIORITURA
%% ==================================================================
\markup \exTitle "7. The fioritura of m. 16, beat 2 (and its variant in m. 24)"
\markup \justify {
Thirteen notes, two passages of the hand: the thumb on A followed by the
fourth finger on A-flat, and the second finger crossing over the thumb
from C-flat to B-flat.
a) Slowly and evenly, forte, with articulated fingers.
b) and c) In the two dotted rhythms.
d) The two crossings isolated.
e) With stops: each group at full speed, leggiero, the hand resting on
the long note and preparing the next group.
Only then as written, pianissimo, the accent on C-flat being a slight
leaning and not a blow.
}
\score {
\new Staff {
\clef treble \key es \major \time 4/4
\mark \markup \small "a)"
\repeat volta 2 {
c'''16-5 b''-4 bes''-3 a''-1 as''-4 f''-3 d''-2 ces''-1
bes'16-2 d''-3 g''-5 f''-4 es''-3 es''8.
}
\break
\mark \markup \small "b)"
\repeat volta 2 {
c'''16. b''32 bes''16. a''32 as''16. f''32 d''16. ces''32
bes'16. d''32 g''16. f''32 es''4
}
\mark \markup \small "c)"
\repeat volta 2 {
c'''32 b''16. bes''32 a''16. as''32 f''16. d''32 ces''16.
bes'32 d''16. g''32 f''16. es''4
}
\break
\time 2/4
\mark \markup \small "d)"
\repeat volta 2 { bes''16-3 a''-1 as''-4 a''-1 bes'' a'' as'' a'' }
\repeat volta 2 { d''16-2 ces''-1 bes'-2 ces''-1 d'' ces'' bes' ces'' }
\time 3/8
\mark \markup \small "e)"
\repeat volta 2 { c'''32-5 b'' bes'' a''-1 as''4-4 }
\repeat volta 2 { as''32-4 f'' d'' ces''-1 bes'4-2 }
\repeat volta 2 { bes'32-2 d''-3 \tuplet 3/2 { g''32-5 f'' es'' } es''4 }
}
\layout { }
}
%% ==================================================================
%% 8. POLYRHYTHMS
%% ==================================================================
\markup \exTitle "8. Four against three (m. 18 beat 1) and eight against three (m. 29 beat 2)"
\markup \justify {
Proceed by successive doublings: two against three, then four, then
eight. The left hand is that of the passage and must remain perfectly
regular; it is the right hand which adapts itself. The single line
under a) and b) gives the resulting rhythm of the two hands together:
tap it first on the closed lid, right and left hand on their own notes.
}
\score {
\new PianoStaff <<
\new Staff {
\clef treble \key es \major \time 3/8
\mark \markup \small "a) 2 : 3"
\repeat volta 2 { es''8.-3 es''8.-2 }
\mark \markup \small "b) 4 : 3"
\repeat volta 2 { es''16.-3 es''-2 es''-1 es''-3 }
\mark \markup \small "c) m. 18"
\repeat volta 2 { \tuplet 4/3 { es''8-.( es''-. es''-. es''-.) } }
}
\new Staff {
\clef bass \key es \major \time 3/8
\repeat volta 2 { as,8 <es c'> <as c' es'> }
\repeat volta 2 { as,8 <es c'> <as c' es'> }
\repeat volta 2 { as,8 <es c'> <as c' es'> }
}
\new RhythmicStaff {
\time 3/8
\repeat volta 2 { c8 c16 c16 c8 }
\repeat volta 2 { c16. c32 c16 c16 c32 c16. }
\repeat volta 2 { s4. }
}
>>
\layout { ragged-right = ##t }
}
\score {
\new PianoStaff <<
\new Staff {
\clef treble \key es \major \time 3/8
\mark \markup \small "d) 2:3"
\repeat volta 2 { es''8. f''8. }
\mark \markup \small "e) 4:3"
\repeat volta 2 { es''16. f'' es'' f'' }
\mark \markup \small "f) 8:3 (m. 29)"
\repeat volta 2 {
\tuplet 8/6 { es''16 f''( es'' f'' es'') f''( es'') f'' }
}
es''4.
\bar "||"
}
\new Staff {
\clef bass \key es \major \time 3/8
\repeat volta 2 { <ces' es' as'>8 <as ces' es'> <es as ces'> }
\repeat volta 2 { <ces' es' as'>8 <as ces' es'> <es as ces'> }
\repeat volta 2 { <ces' es' as'>8 <as ces' es'> <es as ces'> }
es,8 <g es'> <bes es' g'>
}
>>
\layout { ragged-right = ##t }
}
%% ==================================================================
%% 9. REPEATED NOTES WITH CHANGE OF FINGER
%% ==================================================================
\markup \exTitle "9. The repeated note with change of finger (m. 10 beats 1 - 2)"
\markup \justify {
The key must never rise completely: each finger takes the place of the
preceding one at the bottom of its course, and each repetition receives
a slightly different weight.
a) Substitutions on the degrees of the scale, legatissimo.
b) The passage itself with the fingering 3 2 1 3, first in a gradual
diminuendo, then in a gradual crescendo, finally as written
(poco ritenuto).
}
\score {
\new Staff {
\clef treble \key es \major \time 2/4
\mark \markup \small "a)"
\repeat volta 2 {
es''16-4 es''-3 es''-2 es''-1 f''-4 f''-3 f''-2 f''-1
g''16-4 g''-3 g''-2 g''-1 f''-4 f''-3 f''-2 f''-1
}
\time 6/8
\mark \markup \small "b)"
\repeat volta 2 {
es''8-.-3( es''-.-2 es''-.-1 es''-3) d''16( es'' f''16. es''32
es''4.-4) r4.
}
}
\layout { }
}
%% ==================================================================
%% 10. LEGATO CHORDS WITH CHROMATIC INNER PARTS
%% ==================================================================
\markup \exTitle "10. The legato chords of m. 12 (and m. 20), beats 3 - 4"
\markup \justify {
a) The upper part sung and held by the fingers alone (no pedal), the
lower parts staccato and pianissimo.
b) The reverse: the lower parts legato, the upper part detached.
c) Both hands, very slowly, listening to the chromatic motion of each
part and to the enharmonic spellings (F-sharp, B-natural, D-sharp,
G-sharp); crescendo and poco rallentando towards the fp of m. 13.
}
\score {
\new Staff {
\clef treble \key es \major \time 6/8
\mark \markup \small "a)"
\repeat volta 2 {
<< { bes'8--( b'---4 b'-- c''-- c''---4 d''--) }
\\ { f'8-. fis'-. e'-. <e' bes'>-. <f' a'>-. as'-. } >>
}
\mark \markup \small "b)"
\repeat volta 2 {
<< { bes'8-. b'-. b'-. c''-. c''-. d''-. }
\\ { f'8( fis' e' <e' bes'> <f' a'> as') } >>
}
}
\layout { ragged-right = ##t }
}
\score {
\new PianoStaff <<
\new Staff {
\clef treble \key es \major \time 6/8
\mark \markup \small "c)"
<f' bes'>8(\< <fis' b'>-4 <e' b'> <e' bes' c''> <f' a' c''>-4 <as' d''>)
\grace { g'16( bes') es'' } g''4.\fp r4. \bar "||"
}
\new Staff {
\clef bass \key es \major \time 6/8
<bes d'>8 <a dis'> gis g <f c' es'> <bes f'>
es,8 <g es'> <bes es' g'> r4.
}
>>
\layout { ragged-right = ##t }
}
%% ==================================================================
%% 11. THE ARPEGGIO "CON FORZA"
%% ==================================================================
\markup \exTitle "11. The arpeggio con forza (m. 30, beats 1 - 2)"
\markup \justify {
a) The passage of the thumb under the second finger across a minor
third (G, A-flat, C-flat), without any movement of the elbow.
b) The arpeggio in the two dotted rhythms, then with a stop on the top
note.
c) As written: the short trill belongs to exercise 6; the rest of a
thirty-second is a breath, not a hole.
}
\score {
\new Staff {
\clef treble \key es \major \time 2/4
\mark \markup \small "a)"
\repeat volta 2 { g'16-1 as'-2 ces''-1 as'-2 g' as' ces'' as' }
\mark \markup \small "b)"
\repeat volta 2 { g'16.-1 as'32-2 ces''16.-1 es''32-2 as''16.-3 es'''32-5 es'''8 }
\repeat volta 2 { g'32 as'16. ces''32 es''16. as''32 es'''16. es'''8 }
\repeat volta 2 { g'32-1 as' ces''-1 es'' as''-3 es'''16.-5~ es'''4 }
}
\layout { }
}
\score {
\new Staff {
\clef treble \key es \major \time 6/8
\mark \markup \small "c)"
es''8-!-3\f as'16( bes'-3 as'\trill g' as' ces''-1 es''-2 as''-3 es''') r32 f'''32-3(
g'''8 es''') r8 r4. \bar "||"
}
\layout { ragged-right = ##t }
}
%% ==================================================================
%% 12. THE OCTAVES OF THE STRETTO
%% ==================================================================
\markup \exTitle "12. The octaves of the stretto (mm. 30 - 32)"
\markup \justify {
a) The thumb alone, as legato as its sliding allows, the hand keeping
the span of the octave.
b) The upper fingers alone, the fourth on the black keys, legato.
c) The octaves in dotted rhythm, from the wrist, the arm carrying the
hand sideways.
d) The three leaps of m. 31, beats 3 - 4, repeated; then the whole
passage, where the fortissimo of m. 32 must be broad and never hard.
}
\score {
\new Staff {
\clef treble \key es \major \time 12/8
\mark \markup \small "a)"
\repeat volta 2 {
ces'''8-1 bes''-1 beses''-1 as''-1 g''-1 d''-1 es''-1 es'''4.-1 f''8-1 c'''-1
}
\break
\ottava #1
\mark \markup \small "b)"
\repeat volta 2 {
ces''''8-5( bes'''-4 beses'''-5 as'''-4 g'''-5 d'''-5 es'''-4) es''''4.-5 f'''8-5 c''''-5
}
\ottava #0
}
\layout { }
}
\score {
\new Staff {
\clef treble \key es \major \time 4/4
\ottava #1
\mark \markup \small "c)"
\repeat volta 2 {
<ces''' ces''''>8. <bes'' bes'''>16 <beses'' beses'''>8. <as'' as'''>16
<g'' g'''>8. <d'' d'''>16 <es'' es'''>8. <es''' es''''>16
<es''' es''''>4 <f'' f'''>8. <c''' c''''>16 <ces''' ces''''>2
}
\break
\time 2/4
\mark \markup \small "d)"
\repeat volta 2 {
<es'' es'''>8 <es''' es''''>-> <f'' f'''> <c''' c''''>
}
\repeat volta 2 {
<es'' es'''>16 <es''' es''''>8.-> <f'' f'''>16 <c''' c''''>8.
}
\ottava #0
}
\layout { }
}
%% ==================================================================
%% 13. THE CADENZA
%% ==================================================================
\markup \exTitle "13. The cell of the cadenza (mm. 33 - 35)"
\markup \justify {
Four neighbouring keys (A, B-flat, C-flat, C) under the fingers 1 2 3 4:
the difficulty is equality, not speed. Practise first an octave lower.
a) The accent displaced successively onto each of the four notes.
b) The two dotted rhythms.
c) The thumb held down, the other fingers light and close to the keys.
d) The written-out accelerando: each doubling of speed must be
accompanied by a lightening of the touch, so that the crescendo comes
from the accumulation of notes and not from pressure.
}
\score {
\new Staff {
\clef treble \key es \major \time 2/4
\ottava #1
\mark \markup \small "a)"
\repeat volta 2 { ces''''16-3-> bes'''-2 c''''-4 a'''-1 ces''''-> bes''' c'''' a''' }
\repeat volta 2 { ces''''16 bes'''-> c'''' a''' ces'''' bes'''-> c'''' a''' }
\repeat volta 2 { ces''''16 bes''' c''''-> a''' ces'''' bes''' c''''-> a''' }
\repeat volta 2 { ces''''16 bes''' c'''' a'''-> ces'''' bes''' c'''' a'''-> }
\break
\mark \markup \small "b)"
\repeat volta 2 { ces''''16. bes'''32 c''''16. a'''32 ces''''16. bes'''32 c''''16. a'''32 }
\repeat volta 2 { ces''''32 bes'''16. c''''32 a'''16. ces''''32 bes'''16. c''''32 a'''16. }
\mark \markup \small "c)"
\repeat volta 2 {
<< { ces''''16-3 bes'''-2 c''''-4 bes''' ces'''' bes''' c'''' bes''' }
\\ { a'''2-1 } >>
}
\break
\time 4/4
\mark \markup \small "d)"
ces''''8\<-3 bes'''-2 c''''-4 a'''-1
ces''''16 bes''' c'''' a''' ces'''' bes''' c'''' a'''
ces''''32 bes''' c'''' a''' ces'''' bes''' c'''' a'''
ces''''32 bes''' c'''' a''' ces'''' bes''' c'''' a'''\!
bes'''2\fermata
\bar "||"
\ottava #0
}
\layout { }
}
%% ==================================================================
%% 14. THE SYNCOPATED PEDAL
%% ==================================================================
\markup \exTitle "14. The syncopated pedal (m. 1 and the beginning of m. 2)"
\markup \justify {
Left hand alone. The foot rises exactly with the attack of each bass and
goes down again immediately after, while the finger still holds the key:
the notation in tied sixteenths shows the instant of the change. If the
hand leaves the bass before the foot has come down, the bass is lost; if
the foot changes late, the preceding harmony is carried over. Listen to
each bass sounding through the whole beat.
}
\score {
\new Staff {
\clef bass \key es \major \time 12/8
\set Staff.pedalSustainStyle = #'bracket
es,16~ es,16\sustainOn <g es'>8 <bes es' g'>
es16~ es16\sustainOff\sustainOn <as d'>8 <ces' d' as'>
es,16~ es,16\sustainOff\sustainOn <g es'>8 <bes es' g'>
d,16~ d,16\sustainOff\sustainOn <g es'>8 <bes es' g'>
c,16~ c,16\sustainOff\sustainOn <g e'>8 <bes e' g'>
r4.\sustainOff r2. \bar "||"
}
\layout { ragged-right = ##t }
}
GPT-6 Astra: eight well-chosen studies
Astra, which in the earlier tests had not touched a single tool, this time rolled up its sleeves: it wrote the file, compiled it twice, converted it to PDF and to images, and checked it visually for collisions. It handed in eight studies over four pages, each with its source bar, progressive variants A, B, C in boxes, and even its own metronome mark. It gets fairly right which difficulties Cortot would choose, and more or less right the explanations of how to work on them. Its best ideas: studying the octaves and the cadenza an octave lower, in a comfortable register, before returning them to their place, and writing the fioriture with doubled note values before recovering the original rhythm. But it does not match Claude’s: there are fewer formulas and less imagination in the variants, and the explanations are sparser.




📄 GPT-6 Astra’s complete answer
I’ll build progressive studies from the nocturne’s actual figures, isolating the leaps, ornaments, cross-rhythms, chromatic runs and octaves before putting them back into context.
The studies will use the score’s specific notes and rhythms, including the 4:3 and 8:3 figures, the runs in measures 16 and 24, and the octave passage in measure 31. I’m adding preparatory variants and practice directions to each one, then checking that the LilyPond file compiles.
I’m also using the PDF skill to provide a printable score alongside the editable LilyPond code and to check the notation visually.
All eight studies compile without warnings. Each has source measure references and practice directions; the two chromatic-run studies include expanded note values before returning to the original rhythm. I’m checking the four-page score for notation collisions and page breaks.
Created eight original Cortot-inspired studies, using figures from your nocturne. Each includes practice instructions, progressive variants, and precise source references.
Download the complete LilyPond code
| Exercise | Technical focus | Source |
|---|---|---|
| 1 | Left-hand leaps and prepared landings | m. 4, beat 2; m. 29 |
| 2 | Singing melody over quiet accompaniment | m. 1 |
| 3 | Rhythmic variants and short trills | m. 5, beats 2 and 4 |
| 4 | Chromatic movement between hand positions | mm. 6, 14, 22 |
| 5 | Four-against-three and eight-against-three coordination | m. 18, beat 1; m. 29, beat 2 |
| 6 | Expanded and original-speed descending runs | mm. 16 and 24, beat 2 |
| 7 | Octave travel, release and register changes | m. 31 |
| 8 | Cadenza bursts and controlled descent | mm. 33–35 |
The code compiles without warnings. I also visually checked the four-page printable score: :codex-file-citation{path=”[carpeta de trabajo]/output/pdf/nocturne_technical_studies.pdf” purpose=”output”}.
- :codex-followup[Practice schedule]{prompt=”Organize these eight exercises into a progressive two-week practice schedule.”}
- :codex-followup[Additional fingerings]{prompt=”Add suggested fingerings to the chromatic passagework exercises, explaining alternatives for smaller hands.”}
- :codex-followup[MIDI practice tracks]{prompt=”Create slow MIDI practice tracks from these LilyPond exercises.”}
🔧 The code for the eight studies
\version "2.24.4"
\pointAndClickOff
% Original studies inspired by Cortot's analytical practice approach.
% These are newly composed exercises, not quotations from Cortot.
% References are to the user's supplied nocturne, excluding its pickup.
% In that nocturne, one 12/8 beat = one dotted quarter.
% Exercise bar numbers restart in each score and are not source bar numbers.
#(set-global-staff-size 17)
\paper {
#(set-paper-size "a4")
top-margin = 14\mm
bottom-margin = 14\mm
left-margin = 17\mm
right-margin = 17\mm
ragged-last-bottom = ##t
print-page-number = ##t
markup-system-spacing.basic-distance = #15
score-markup-spacing.basic-distance = #16
}
\header {
title = "Eight Analytical Studies for the Nocturne"
subtitle = "Original exercises inspired by Alfred Cortot's approach"
composer = "Based on the supplied E-flat major nocturne"
tagline = ##f
}
\layout {
indent = 0
\context { \Score \override BarNumber.break-visibility = ##(#f #f #f) }
}
\markup \wordwrap {
Work slowly in short, relaxed repetitions. Each study isolates a movement,
varies it, then approaches the original figure. Tempos are starting points.
Play without pedal first; restore expressive shaping when the movement is secure.
Fingerings are suggestions except where explicitly taken from the source.
}
\markup \vspace #1
\markup \bold "1. Left-hand displacement and silent preparation"
\markup \wordwrap {
Source: m. 4, beat 2; m. 29, beats 1-2. A: release the bass immediately,
travel during the rest and touch the next chord silently before sounding it.
B: join the original patterns. Keep the upper chords softer than the bass;
move the arm instead of stretching across the distance.
}
\score {
\new Staff {
\clef bass \key es \major \time 2/4 \tempo 4 = 48
\mark \markup \box "A: prepare the landing"
bes,,8-5\p r8 <f d'>8 r8 |
as,,8-5 r8 <es as ces'>8 r8 | \break
\time 12/8 \tempo 4. = 36
\mark \markup \box "B: continuous motion"
\repeat unfold 4 { bes,,8 <f d'> <bes as'> } |
as,,8 <es as ces'> <as ces' es'>
<ces' es' as'> <as ces' es'> <es as ces'>
es, <g es'> <bes es' g'> es <g es'> <bes es' g'> |
\bar "|."
}
}
\markup \bold "2. Singing over a moving accompaniment"
\markup \wordwrap {
Source: m. 1. A reduces the melody to its sustained outline; B restores
the actual rhythm. Listen through each long note while making the left hand
recede. Do not reattack the tied G at beat 2. After balancing without pedal,
change pedal with each dotted-quarter beat, listening for clean harmony.
}
balanceLH = {
es,8\pp <g es'> <bes es' g'> es <as d'> <ces' d' as'>
es, <g es'> <bes es' g'> d, <g es'> <bes es' g'> |
}
\score {
\new PianoStaff <<
\new Staff {
\clef treble \key es \major \time 12/8 \tempo 4. = 36
\mark \markup \box "A: melodic outline"
g''2.\p( f''4. es''4.) | \break
\mark \markup \box "B: original melody"
g''4.~( g''8 f'' g'' f''4. es''4) bes'8 | \bar "|."
}
\new Staff {
\clef bass \key es \major \time 12/8
\balanceLH \balanceLH
}
>>
}
\pageBreak
\markup \bold "3. Neighbour-note agility and the short trill"
\markup \wordwrap {
Source: m. 5, beats 2 and 4. Practise each line separately: long-short,
short-long, even notes, then the ornamented source figure. Keep the wrist
free and the thumb quiet. The final ornament belongs within its note's time;
do not add a beat. Rejoin m. 5 only after both cells are easy.
}
\score {
\new Staff \relative f'' {
\key es \major \time 3/8 \tempo 4. = 30
\mark \markup \box "A: F cell"
f16.-3\p( g32-4 f16.-3 e32-2 f16.-3 g32-4) |
f32( g16. f32 e16. f32 g16.) |
f16( g f e f g) |
f16( g f\prall e f g) | \break
\mark \markup \box "B: E-flat cell"
es16.-3( f32-4 es16.-3 d32-2 es16.-3 f32-4) |
es32( f16. es32 d16. es32 f16.) |
es16( f es d es f) |
es16( f es\prall d es f) | \bar "|."
}
}
\markup \bold "4. Chromatic hand positions and rhythmic variants"
\markup \wordwrap {
Source: m. 6, beats 1-2, also mm. 14 and 22. A: learn the contour evenly.
B and C: redistribute time without changing pitch order. D: restore m. 6
over its accompaniment. Prepare each new position during the preceding
note; avoid turning every black-key group into an accent.
}
\score {
\new PianoStaff <<
\new Staff \relative g'' {
\key es \major \time 6/8 \tempo 4. = 30
\mark \markup \box "A: even"
g16\p b, c des( c) f( e) as( g) des'( c g) |
\mark \markup \box "B: long-short"
g16. b,32 c16. des32 c16. f32 e16. as32 g16. des'32 c16. g32 | \break
\mark \markup \box "C: short-long"
g32 b,16. c32 des16. c32 f16. e32 as16. g32 des'16. c32 g16. |
\time 12/8
\mark \markup \box "D: restore the phrase"
g16\< b, c des( c) f( e) as( g) des'( c g
bes4.\!\> as4 g8)\! | \bar "|."
}
\new Staff {
\clef bass \key es \major \time 6/8
R2. | R2. | R2. | \time 12/8
c8\pp <g e'> <bes e' g'> c <g e'> <c' e' bes'>
f, <f des'> <bes des' e'> f, <f c'> <as c' f'> |
}
>>
}
\pageBreak
\markup \bold "5. Four against three; eight against three"
\markup \wordwrap {
Source: m. 18, beat 1; m. 29, beat 2. Each exercise bar equals ONE source
beat. A: four RH attacks against three LH attacks. B: eight RH attacks
against three LH attacks. First tap the rhythms; then play the source pitches.
In a 12-part grid, A uses RH 1,4,7,10 and LH 1,5,9. In a 24-part grid,
B uses RH 1,4,7,10,13,16,19,22 and LH 1,9,17. Finally feel one broad pulse.
}
\score {
\new PianoStaff <<
\new Staff {
\key es \major \time 3/8 \tempo 4. = 24
\set tupletFullLength = ##t
\override TupletNumber.text = #tuplet-number::calc-fraction-text
\mark \markup \box "A: four in the time of three"
\repeat unfold 2 {
\times 3/4 { es''8-3\p( es''-2 es''-1 es''-3) } |
} \break
\mark \markup \box "B: eight in the time of six sixteenths"
\repeat unfold 2 {
\times 6/8 { es''16\p( f'' es'' f'' es'' f'' es'' f'') } |
}
\bar "|."
}
\new Staff {
\clef bass \key es \major \time 3/8
\repeat unfold 2 { as,8\pp <es c'> <as c' es'> | }
\repeat unfold 2 { <ces' es' as'>8 <as ces' es'> <es as ces'> | }
}
>>
}
\markup \bold "6. Rapid descents: expand, group, restore"
\markup \wordwrap {
Source: m. 16, beat 2, and m. 24, beat 2. A and C double every duration;
B and D restore the written values at the same dotted-quarter pulse.
Keep the triplets proportional. The concluding E-flat is the destination,
not a fresh accent. Fingerings in the m. 16 descent follow the source.
}
\score {
\new Staff {
\key es \major \time 6/8 \tempo 4. = 26
\mark \markup \box "A: m. 16 expanded"
\relative c''' {
c16-5\p( b-4 bes-3 a-1 as-4 f-3 d-2 ces
bes-2 d-3 \tuplet 3/2 { g16 f es-3 }) |
}
\time 3/8
\mark \markup \box "B: original values"
\relative c''' {
c32-5( b-4 bes-3 a-1 as-4 f-3 d-2 ces
bes-2 d-3 \tuplet 3/2 { g32 f es-3 }) |
es4.-2 |
} \break
\time 6/8
\mark \markup \box "C: m. 24 expanded"
\relative bes'' {
bes8( a-1 as-4 \tuplet 3/2 { a,16 bes c }
cis16 d-1 \tuplet 3/2 { g16-5 f es }) |
}
\time 3/8
\mark \markup \box "D: original values"
\relative bes'' {
bes16( a-1 as-4 \tuplet 3/2 { a,32 bes c }
cis32 d-1 \tuplet 3/2 { g32-5 f es }) |
es4. |
}
\bar "|."
}
}
\pageBreak
\markup \bold "7. Octave travel without a fixed wrist"
\markup \wordwrap {
Source: m. 31. A traces the lower-note contour one octave below the source,
with the thumb alone: detach gently and move the arm. B uses octaves at that
practice register; C restores the source register. The leap to the high
E-flat occurs on the second eighth of beat 3. Begin at p; add the original
intensity only after the travel is easy. Release between repetitions.
}
\score {
\new Staff {
\key es \major \time 12/8 \tempo 4. = 30
\mark \markup \box "A: thumb route, octave lower"
\relative ces'' {
ces8-1\p-. bes-1-. beses-1-. as-1-. g-1-. d-1-.
es-1-. es'4.-1 f,8-1-. c'-1-. |
} \break
\mark \markup \box "B: relaxed octaves, octave lower"
\relative ces'' {
<ces ces'>8\p <bes bes'> <beses beses'> <as as'> <g g'> <d d'>
<es es'> <es' es'>4. <f, f'>8 <c' c'> |
} \break
\mark \markup \box "C: source register"
\ottava #1
\relative ces''' {
<ces ces'>8\mp <bes bes'> <beses beses'> <as as'> <g g'> <d d'>
<es es'> <es' es'>4.-> <f, f'>8 <c' c'> |
}
\ottava #0 \bar "|."
}
}
\markup \bold "8. Cadenza cell: speed, release and controlled descent"
\markup \wordwrap {
Source: mm. 33-35. A-C practise the four-note cell one octave below the
source, using its 3-2-4-1 fingering. A: spacious notes. B: brief bursts with
full release in the rests. C: join four cells without a new accent on each
thumb. D restores the source register and m. 35 descent. Gradually slow and
soften the descent; return to m. 36 only after the hand has released.
}
\score {
\new Staff {
\key es \major \time 2/4 \tempo 4 = 40
\ottava #1
\mark \markup \box "A: spacious cell"
\relative ces''' {
ces16-3\p( bes-2 c-4 a-1) ces-3( bes-2 c-4 a-1) |
}
\mark \markup \box "B: bursts and release"
\relative ces''' {
ces32-3( bes-2 c-4 a-1) r8 ces32-3( bes-2 c-4 a-1) r8 |
} \break
\mark \markup \box "C: continuous, supple"
\relative ces''' {
\repeat unfold 4 { ces32-3( bes-2 c-4 a-1) } |
}
\mark \markup \box "D: original register and descent"
\ottava #2
\relative ces'''' {
ces32\p( bes d c bes a as g f d es c bes as c, d)\pp |
}
\ottava #0 \bar "|."
}
}
Gemini 3.1 Pro: four exercises and a good speech
Gemini used no tools, did not compile, and handed in four exercises on one page. Its explanation of Cortot’s principles is among the best in words: silent touches to measure the keyboard’s topography, the held thumb to make the fingers independent, the blocks separated by fermatas in the fioritura. But on paper it stays generalist: four difficulties where the others see eight and fourteen, and the cadenza, which it had itself called “the famous Senza tempo cadenza” in its diagnosis, was left with no exercise.

📄 Gemini 3.1 Pro’s complete answer, with its code
To help a student conquer the specific technical challenges of Chopin’s Nocturne Op. 9 No. 2, Alfred Cortot would typically provide an Édition de travail (Working Edition). Cortot’s pedagogical philosophy heavily utilized rhythmic variations, blocking (playing broken chords simultaneously), finger independence drills (holding certain notes while articulating others), and exaggerating the difficulty to make the final performance feel effortless.
Here is the LilyPond code containing four custom technical exercises based on the most demanding passages we identified earlier, composed strictly in Cortot’s pedagogical style:
\version "2.24.4"
\header {
title = "Technical Exercises for Nocturne Op. 9 No. 2"
subtitle = "In the Style of Alfred Cortot's Éditions de Travail"
composer = " "
tagline = ##f
}
\paper {
markup-system-spacing.basic-distance = #15
system-system-spacing.basic-distance = #15
}
\layout {
indent = 0\mm
\context {
\Score
\remove "Bar_number_engraver"
}
}
% --- EXERCISE 1 ---
\score {
\new Staff {
\clef bass
\key es \major
\time 6/8
\absolute {
<>^\markup { \bold "Exercise 1: Left-Hand Leaps and Spatial Awareness (Ref. mm. 1-2)" }
^\markup { \italic "a) Play the bass note and instantly move to touch the chord silently (diamond noteheads)." }
es,8[ \once \override NoteHead.style = #'harmonic-mixed <g es'>8 \once \override NoteHead.style = #'harmonic-mixed <bes es' g'>8]
d,8[ \once \override NoteHead.style = #'harmonic-mixed <g es'>8 \once \override NoteHead.style = #'harmonic-mixed <bes es' g'>8] | \bar "||" \break
<>^\markup { \italic "b) Rapid displacement: Play the bass note as a quick grace note to feel the arm travel." }
\grace { es,8 } <g es'>8[ r <bes es' g'>] \grace { d,8 } <g es'>8[ r <bes es' g'>] | \bar "|."
}
}
}
% --- EXERCISE 2 ---
\score {
\new Staff {
\clef treble
\key es \major
\time 4/4
\absolute {
<>^\markup { \bold "Exercise 2: Finger Independence for the Turn (Ref. m. 2)" }
^\markup { \italic "a) Hold the thumb while articulating the upper fingers evenly. (Fingering 1-4-3-2)" }
\set fingeringOrientations = #'(up)
<<
{ d''16-4( c''-3 b'-2 c''-3) d''( c'' b' c'') d''( c'' b' c'') d''( c'' b' c'') }
\\
{ c''2-1 c''2-1 }
>> | \bar "||" \break
<>^\markup { \italic "b) Practice the turn with varied rhythms to gain control." }
\time 2/4
c''8-1 d''16.-4 c''32-3 b'16.-2 c''32-3 c''8-1 |
\tuplet 3/2 { c''8-1 d''-4 c''-3 } \tuplet 3/2 { b'8-2 c''-3 c''-1 } | \bar "|."
}
}
}
% --- EXERCISE 3 ---
\score {
\new Staff {
\clef treble
\key es \major
\time 6/8
\absolute {
<>^\markup { \bold "Exercise 3: Voicing and Legato in Double Notes (Ref. m. 12)" }
^\markup { \italic "a) Play the upper voice strictly legato, and the lower notes lightly staccato to prevent tension." }
<<
{ \stemUp es''4.( d''8 c'' d'') }
\\
{ \stemDown g'4. a'8-. a'-. a'-. }
>> | \bar "||" \break
<>^\markup { \italic "b) Hold the upper melodic note while repeating the inner voice." }
<<
{ \stemUp d''4. d''4. }
\\
{ \stemDown a'16( g' a' g' a' g') a'( g' a' g' a' g') }
>> | \bar "|."
}
}
}
% --- EXERCISE 4 ---
\score {
\new Staff {
\clef treble
\key es \major
\time 3/8
\absolute {
<>^\markup { \bold "Exercise 4: Mastering the Fioritura (Ref. m. 16)" }
^\markup { \italic "a) Practice with stopping points (fermatas) to organize the mind and group the hand positions." }
c'''32[-5 b''-4 bes''-3 a''-1] \fermata as''[-4 f''-3 d''-2 ces''-1] \fermata bes'[-2 d''-3 g''-5 f'']-4 \fermata es''8-3 | \bar "||" \break
<>^\markup { \italic "b) Dotted rhythms for extreme articulation and brilliance." }
c'''32.[ b''64 bes''32. a''64] as''32.[ f''64 d''32. ces''64] bes'32.[ d''64 g''32. f''64] es''8 | \bar "|."
}
}
}
How Cortot’s Principles are Applied Here:
-
Exercise 1 (Left Hand Leaps): Rather than just practicing it slowly, Cortot forces the brain to internalize the physical distance. Variant
1auses silent touches to map the topography of the keyboard without the pressure of producing sound. Variant1bturns the leap into a grace note to force the arm to move instantly. - Exercise 2 (The Turn): A classic Cortot finger-independence drill. By physically holding down the thumb (C), the 2nd, 3rd, and 4th fingers are forced to articulate clearly without relying on wrist rotation. Rhythmic variants follow to lock in muscle memory.
-
Exercise 3 (Double Notes): To achieve a bel canto top line, Cortot isolates the mechanics. Variant
3aforces the student to play the melody legato while keeping the inner voice detached—preventing the hand from cramping. Variant3brequires holding the melodic note while the inner fingers stay active. -
Exercise 4 (The Fioritura): For massive, unmeasured runs, Cortot never suggested practicing straight through. Variant
4abreaks the run into manageable physical “blocks” separated by fermatas, allowing the mind to prepare the next hand position. Variant4buses dotted rhythms to build raw finger speed and brilliance.
The cadenza, year by year
If there is one passage to measure all this, it is the ad libitum cadenza of bars 33 to 35: four neighbouring notes, C flat, B flat, C and A, repeated at full speed. In 2024 Claude did not spot it, I had to ask about it directly, and it answered this:

With the wrong notes, to begin with: it forgot the flat on the C. That day I closed the post with this line:
However, the intelligence that Cortot displayed in proposing the exercise for this passage is not yet present in the language model… for now.
By 2025 it already included it without being asked, and with the right notes. But look at variants A, C and D: “regular tempo”, “gradual acceleration” and “gradual deceleration” are, on paper, exactly the same music under a different label. The study lives in the caption, not in the formula:

In 2026, Claude and Astra bring it as standard. Look at Claude’s exercise 13, at the end of its fifth page: “Four neighbouring keys under the fingers 1 2 3 4: the difficulty is equality, not speed.” Practise first an octave lower; the accent displaced successively onto each of the four notes; the two dotted rhythms; the thumb held down with the other fingers light and close to the keys; and a written-out accelerando, from eighth notes to thirty-second notes, where “each doubling of speed must be accompanied by a lightening of the touch, so that the crescendo comes from the accumulation of notes and not from pressure”. That is no longer repeating a fragment. That is understanding why the passage is difficult.
Gemini, like Claude in 2024, had to be asked using that same old prompt. And it answered well: displaced accents, dotted rhythms, dry staccato from the knuckle, and one fine idea that did not occur to the others, playing the four-note cell in triplets so the accent lands on a different finger each time. A shame about the layout, with the texts stacked on top of each other and cut off at the margin: what happens when you don’t look at what you deliver.

📄 Gemini 3.1 Pro’s complete answer about the cadenza, with its code
In measures 33, 34, and 35, there is an ad libitum cadence with notes that can be played very quickly. What exercise in the style of Alfred Cortot would you write in Lilypond code to work on the clear articulation of each note in the groups?
To master the rapid, undulating Senza tempo cadenza in measures 33-35, Alfred Cortot’s approach focuses on combatting the hand’s natural tendency to “roll” or blur repeating patterns. To achieve crystal-clear articulation, the brain must be forced to actively command every single finger independently.
Cortot achieved this through shifting accents, metric displacement (forcing a 4-note pattern into a 3-note rhythm), and extreme rhythmic variations.
Here is a LilyPond exercise block written in Cortot’s exact pedagogical style to build absolute clarity and finger independence for this specific cadenza (fingering: 3 on C-flat, 2 on B-flat, 4 on C-natural, 1 on A-natural):
\version "2.24.4"
\header {
title = "Technical Exercises for Nocturne Op. 9 No. 2"
subtitle = "Mastering the Cadenza (Measures 33-35)"
composer = " "
tagline = ##f
}
\paper {
markup-system-spacing.basic-distance = #15
system-system-spacing.basic-distance = #15
}
\layout {
indent = 0\mm
\context {
\Score
\remove "Bar_number_engraver"
}
}
\score {
\new Staff {
\clef treble
\key es \major
\absolute {
<>^\markup { \bold "Exercise 5: Clear Articulation for the Cadenza (Ref. mm. 33-35)" }
^\markup { \italic "a) Shifting Accents: Accent a different finger on each repetition to equalize finger strength." }
\time 4/4
ces''16->-3( bes'-2 c''-4 a'-1) ces''16-3( bes'->-2 c''-4 a'-1) ces''16-3( bes'-2 c''->-4 a'-1) ces''16-3( bes'-2 c''-4 a'->-1) | \bar "||" \break
<>^\markup { \italic "b) Metric Displacement: Play the 4-note pattern as triplets. The accent naturally shifts to a new finger." }
\time 12/8
ces''8->-3( bes'-2 c''-4) a'->-1( ces''-3 bes'-2) c''->-4( a'-1 ces''-3) bes'->-2( c''-4 a'-1) | \bar "||" \break
<>^\markup { \italic "c) Rhythmic Variants: Use dotted rhythms for 'snap' and extreme clarity." }
\time 2/4
ces''16.-3( bes'32-2 c''16.-4 a'32-1) ces''32-3( bes'16.-2 c''32-4 a'16.-1) | \bar "||" \break
<>^\markup { \italic "d) Articulation: Play very slowly with a strong, dry staccato (from the knuckle, without pedal)." }
\time 2/4
ces''16-.-3 bes'-.-2 c''-.-4 a'-.-1 ces''16-. bes'-. c''-. a'-. | \bar "|."
}
}
}
Why these exercises work (The Cortot Method):
- Variant A (Shifting Accents): When playing fast, the thumb (1) and middle finger (3) naturally dominate. By forcing the accent onto the 2nd and 4th fingers on subsequent beats, you build equality across the hand.
- Variant B (Metric Displacement): This was one of Cortot’s favorite tricks. By putting a 4-note physical pattern into a 3-note musical meter (triplets), the strong beat automatically rotates through the fingers. On beat 1, finger 3 is accented. On beat 2, finger 1. On beat 3, finger 4. On beat 4, finger 2.
- Variant C (Dotted Rhythms): This builds fast-twitch muscle reflexes. It teaches the fingers to fire instantly and then relax, creating the “pearl-like” brilliance Chopin requires.
- Variant D (Staccato): Playing a legato passage heavily staccato removes the crutch of the wrist and pedal, forcing the knuckle joints to do 100% of the mechanical work. When you return to playing it legato and fast, it will feel incredibly light and articulate.
Three years in one table
| Diagnosis | Invents things | Exercises | Form | The cadenza | Checks what it delivers | |
|---|---|---|---|---|---|---|
| 2024 · Claude 3.5 | Generic; concrete only when pressed | Yes: a polyrhythm that doesn’t exist | Few; repeat fragments | Loose staves | Only when asked, and with wrong notes | No |
| 2024 · GPT-4o | Generic; advice that doesn’t come from the score | Yes | The code doesn’t compile | Can’t be seen | No | No |
| 2025 · Claude | Concrete, with examples | A little | 8, with lots of text | Cortot-style prose | Yes, on its own initiative | No |
| 2026 · Claude Fable 5.1 | Meticulous, with bar and beat | I haven’t found any | 14, over 6 pages | Text and lettered formulas, like Cortot | Yes, by default | Yes, three rounds |
| 2026 · GPT-6 Astra | Orderly and concrete | I haven’t found any | 8, over 4 pages | Variants A, B, C with their source | Yes, by default | Yes |
| 2026 · Gemini 3.1 Pro | Correct, more schoolish | One miscount | 4, on 1 page | Exercises with instructions | Only when asked; well resolved | No |
What I take away
The “for now” has expired. In 2024 I wrote that Cortot’s intelligence was not in the language model, for now. I am not going to say that Claude is Cortot. But exercise 13 reasons the way a good teacher reasons: it identifies which is the real difficulty, which is not the one it looks like, and designs the study from there. Two years ago that wasn’t there. Today it is.
From advice that fits anything to bar and beat. What in 2024 had to be dragged out with a second prompt, and came out riddled with inventions, today arrives on the first try and holds up under checking. With the caveat I have already confessed: this time I asked for the precision up front.
Once again, whoever looks at what it delivers wins. Third post, and the third time the same thing happens. Claude compiled, looked at its six pages and corrected until satisfied. Astra, which never used to use tools, this time compiled and checked, and its result rose. Gemini looked at nothing, and delivered less, with the texts overlapping each other.
The shadow of memory. Two of the three recognised the piece, and Claude even corrected my tempo with Chopin’s original marking. How much of these diagnoses is reading the code, and how much is remembering everything that has been written about the most famous nocturne in the world, Cortot’s edition included? I don’t know. That is why the natural next step is to repeat the lane with the three nocturnes they themselves invented in the previous post: on a piece that did not exist yesterday, no memory can help.
And what about the teacher? To write this post I have had to know whether thirteen notes really were thirteen, whether a fingering can actually be played, and whether an exercise resembles Cortot or merely name-drops him. The tool already gives serious study material, and that can save an advanced student hours of badly framed practice. But someone has to know how to tell Claude’s fourteen exercises apart from Gemini’s four. That someone is still us.
The usual caution: one run per model, different families and generations, and a single judge — me.
What’s next
The lane on the invented nocturnes, to take away the safety net of memory. The recognition-in-gradient test: the same piece stripped bare, transposed, in one hand only, and with no indications at all. And the typos: five wrong notes hidden in the nocturne, to see who finds them.
Play it, compose it, study it… If this keeps up, one of these days I’ll ask them to walk out on stage. That’s when we’ll really see.
Transparency. This draft was written by Claude Fable 5.1 (Anthropic) from the log of the test, translated by it from my Spanish original, and reviewed by me. The conflict of interest is total: it is one of the three candidates, and the one that comes off best. That is why the assessment of the exercises is mine, as a pianist and teacher; the models’ answers are reproduced in full and untouched, except for the folder paths on my computer, which I have replaced with the placeholder “[carpeta de trabajo]” (Spanish for “working folder”); and the checks against the score are made on the code.