Every skill in the L3 style layer must first answer one question:
Within this style, which things are "specific to it," and which are just general music theory wearing a coat of this style?
For jazz this question is especially sharp, becausejazz theory is widely taught as "advanced music theory"——
many things actually belong to mc-harmony, not to this skill.
Which sections to read by task
| Task | Read |
|---|---|
| Deciding whether a technique should be carried over to another style | ★ §2 transfer table (read this first） |
| Writing jazz harmony | §3 chord–scale |
| Wanting altered dominants, wanting an "outside" sound | §3.3 melodic minor |
| Comping | §4 |
| Laying out the structure of a jazz tune | §5 |
| Writing a solo / improvisation section | §6 |
| What actually differs between jazz arranging and pop arranging in practice | ★ §7 |
Boundaries
| Not handled here | Where it belongs |
|---|---|
| Thegeneral usage | mc-harmony §6、§7（★ They are not exclusive to jazz） |
| The definition of church modes | mc-melody reference.md §2 |
| How the quantization ratio of swing is determined | mc-rhythm-section §2 (percentage quantization); this library does not give millisecond values, swing is written as a ratio into groove.quantize_policy |
| General principles of form | mc-form |
| Instrumentation | mc-orchestration |
| A complete catalog of scales/chords/voicings | reference.md |
1. Must fill in before starting
| Required | Question |
|---|---|
| ① Which branch of jazz | swing / bebop / modal / bossa / fusion / jazzy pop."Jazz" is not one style. Bossa's groove, instrumentation, and chord-change timing are in mc-style-latin, here we only handle the harmony it borrows |
| ② Is this jazz or "jazzy" | ★ Determines how to use the §2 transfer table |
| ③ Is there an improvisation section | If so the form is completely different (§5) |
| ④ Ensemble size | ★ Measured: median roster in the jazz corpus is 22 tracks, pop is 36——jazz is subtractive |
2. ★ Transfer table: what can and cannot be carried over
The architecture document requires every L3 skill to include this table. This is the key to preventing style contamination.
| Technique | Can it be carried over | Explanation |
|---|---|---|
| ii–V–I, secondary dominants, substitute chords | ✅ Fully transferable | They are already in mc-harmony . J-POP and city pop use them heavily |
| Tension notes (9/11/13) | ✅ Transferable | Same as above. Butdensity must be lowered——full tension voicings in pop turn muddy |
| Chord–scale thinking | ⚠️ Half transferable | Asa basis for note selectiontransferable; asan improvisation frameworknot transferable (pop songs have no improvisation section) |
| The four usable chords of melodic minor | ⚠️ Half transferable | Used individually (e.g. Lydian Dominant as a color) it is transferable;used in a string it will immediately sound like jazz |
| Altered dominant (Altered) | ❌ Basically not transferable | As soon as it enters pop it is "jazzy", not "sophisticated" |
| Diminished scale lick | ❌ Not transferable | A strong marker of jazz vocabulary |
| Jazz usage of sus chords | ⚠️ Half transferable | ★ Fractional dominant substitutes like F/G are a mainstay in city pop（→ mc-progressions reference §3） |
| The rhythm of comping | ❌ Not transferable | It assumes there is an improviser who needs space left for them |
| Head–Solos–Head form | ❌ Not transferable | Pop songs do not have this structure |
| Swing groove | ⚠️ Half transferable | Shuffle is common in blues rock and R&B, butthe swing ratio is different |
| Small ensemble, lots of space | ✅ Transferable, and it should be transferred | See §7 |
★ One criterion：
Whether it can be transferred depends on whether it assumes "someone is improvising". Those that assume it (comping rhythm, solo structure, handling of outside notes) cannot be transferred; those that do not assume it (harmonic resources, ensemble philosophy) can be transferred.
3. Chords–Scales
3.1 Core idea
Each chord corresponds to one (or several) scales, and the scale determines the available notes. This is the biggest difference in thinking between jazz theory and classical functional harmony: Classical asks "where does this note need to resolve to", jazz asks "which notes can be used on this chord".
| Mode | Chord |
|---|---|
| Ionian | △7 |
| Dorian | m7 |
| Mixolydian | dominant 7 |
| Aeolian | m7 (natural minor color) |
| Locrian | m7(♭5)(half-diminished) |
| Lydian | △7(♯11) |
| Phrygian | Sus♭9 |
3.2 Avoid Note
It is not "cannot be used", it is "cannot stop on it". Most typical: in a major II-V-I,the 4th degree on I△7(a semitone conflict with the third).
★ This is where Lydian is useful: raise the 4 to ♯4,the avoid note disappears, so △7(♯11) is more "open" than △7. The same applies to ♯11 on a dominant seventh.
Levine spent an entire chapter discussing "a reconsideration of dissonant notes"—the history of jazz is precisely the continuous incorporation of notes that were originally "unusable".
3.3 ★ Melodic minor harmony: the most core part of jazz
The melodic minor scale has 7 modes, four of which give the signature chords of jazz:
| Mode | Chord | Use |
|---|---|---|
| 1st degree | minor-major seventh (mMaj7) | the jazz version of the minor tonic chord |
| 2nd degree | Sus♭9 | |
| 3rd degree | Lydian Augmented | |
| 4th degree | Lydian Dominant(belongs to 7♯11) | ★ Most commonly used, andeasiest to move into pop |
| Degree 6 | Half-diminished (m7♭5) | The II of the minor ii-V |
| Degree 7 | ★ Altered dominant (Altered) | The core of the jazz sound |
★★ Interchangeability： These chords generated from the same melodic minor scale can substitute for one another. This is "tonal thinking"—what you're thinking about is not a single chord, but **"which melodic minor we're on right now"**.
This point is the greatest divide between jazz and pop harmony. Pop harmony isa sequence of chords; jazz harmony isa sequence of scale regions, and chords are merely its slices.
3.4 Other Resources
| Resource | Use |
|---|---|
| Diminished scale | Pairs with dim7 and V7♭9. ★ The diminished seventh chord is the "disguise" of V7♭9—after bebop, V7♭9 is used directly to replace the diminished chord.Repeating in minor thirdsthe pattern lets one voicing work for multiple V7♭9 |
| Whole-tone scale | Pairs with augmented chords, V7♯5 |
3.9 ★ Blues Harmony: The Shared Foundation of Jazz, Rock, and R&B (Chen Yunqiang)
This library previously had only the one line "the friction of ♭3 ♭5 ♭7." Blues harmony is a whole system; page numbers come from 《Jazz Harmony》.
The functional skeleton cannot be moved(p0192): the first four bars are tonic function I7, the fifth and sixth bars are subdominant IV7, the ninth and tenth bars are the cadence. ★ Only in blues can the I degree use a dominant seventh as tonic function（p0187）。
The evolution of four basic progressions(p0186–0187): from major triads using only I and IV → all turned into dominant sevenths → the last four bars add IV–V–I → the last four bars change to V–IV–I。 ★ Reverse cadence is a feature unique to blues。
Three positions that can be varied(p0192–0193): weak positions in harmonic rhythm, the junctions between functional sections, and between chord and chord. Common bar-by-bar variations (p0193–0195):
| Bar | Variation |
|---|---|
| 2 | I7 → IV7 |
| 4 | I7 → III-7♭5 (equals I9 with the root omitted) |
| 5 | Add I7 after IV7 |
| 6 | Add after IV7 ♯IV°7(equals IV7 with ♭9 and the root omitted), so the I7 in bar 7 uses an inversion, with the fifth as the bass, making the bass of IV → ♯IV° → I/5ascend chromatically |
| 8 | What to add is determined by the first chord of bar 9: if it is II-7, add V7/II; if it is IV7, add III-7♭5 |
| 9–10 | Variable II-7 – V7 – I7 – ♭VII7 |
| 11–12 | Add secondary dominants or extended dominants |
★ Determination is unbound from form(p0196): if it uses I7, IV7 plus the blues scale (1 ♭3 4 ♯4 5 ♭7), it is blues,not necessarily twelve bars, eight bars and sixteen bars are equally common.
Tension:the 11th of I7, IV7, and V7 are all unavailable; I7 can use ♭3 as ♯9 (p0189–0190).
The minor-second clash between harmony and scale is exactly the flavor of blues, mutually corroborating with mc-melody reference §4.
mc-style-rock-band and mc-harmony both take their skeleton from here.
4. Comping (accompaniment)
The whole essence of comping is: leave space for the improviser.
| Principle | Explanation |
|---|---|
| Don't fill it up | ★ This is the biggest difference from pop accompaniment. Pop accompaniment occupies a stable position in the texture; comping goes in and out |
| Respond rather than set up | Listen to what the improviser just played and react to it |
| Voicings omit the root | Leave the bass to the bass.The third and seventh are the skeleton（guide tones） |
| Voicing of sus chords | Levine has a dedicated section (p0064)—it is the sound of "non-resolution" |
★ Transplant warning（§2）：The rhythm of comping cannot be transplanted into pop. In pop there is no improviser, and those gaps turn into holes.
4.1 Guide-tone lines: how to write inner voices (Chen Yunqiang p0093–0096)
§4 said the third and seventh are the skeleton; this section gives the method.
Characteristic tones: the third and seventh of seventh chords; the third and sixth of sixth chords;for chords with an altered fifth such as diminished seventh, half-diminished, and augmented seventh, the fifth is also a characteristic tone。
Connection rules: when the root moves by a fifth, fourth, or third, do 3 → 7 or 7 → 3; when the root moves stepwise, by a third, or stays put, do 3 → 3 or 7 → 7 moving in the same direction (for a third, either is optional).
Four adjustments, to prevent the line from being monotonous or the voices from being too high or too low: add the root or fifth (add available extensions when necessary); make an octave leap when the chord is sustained; swap the third and seventh when the chord is sustained; rearrange the starting note after a section of harmony ends.
★ It is not only for jazz: this is just the writing of an inner voice or contrapuntal line, and it can be used just as well for writing a counter-melody. The melody of All The Things You Are is mainly made up of guide-tone lines.
mc-counterpoint §3 discussed relative motion; here we discuss choosing notes.
5. Form: Head–Solos–Head
Head（主题，一遍或两遍）
→ Solo 1（按 head 的和声循环若干遍）
→ Solo 2 …
→ （4s / 8s：与鼓手交换乐句）
→ Head（再来一遍）
→ 尾（tag / 渐弱 / 定型结尾）
★ The fundamental difference from pop form：
- The pop structure is "a sequence of content"(the verse talks about this, the chorus talks about that)
- The jazz structure is "the same harmonic cycle walked many times", with the content filled in by the improviser each time
So form[].bars has a different meaning in jazz:
it is "how many bars are in one chorus" (32-bar AABA is standard),not "how long this section is"。
Common head forms: AABA (32 bars), ABAC, 12-bar blues. For ready-made repertoire see .
6. Bebop phrasing
From Valerio:
| Element | Key point |
|---|---|
| Harmonic basis | Extensions + Alterations |
| Interlocking triads and seventh chords | Use upper-structure triads to express complex chords |
| Harmony–melody improvisation | The improvised line is simultaneously a statement of the harmony |
| Rhythm | — |
| Phrasing | — |
| Accents | ★ One of bebop's hallmarks isaccents falling on the offbeat |
| Contour | — |
Historical lineage: Ragtime → Blues → Swing → Bebop. ★ Knowing this lineage is useful because **the word "jazz" refers to different music in different eras** (§1①).
7. ★ Field test: the difference between jazz arranging and pop arranging
Cambridge-MT corpus, 10 jazz-acoustic tracks vs the rest:
| Metric | jazz-acoustic | pop | rock | hiphop-rnb |
|---|---|---|---|---|
| Roster size (median) | ★ 22 tracks | 36 | 30 | 37 |
| Number of sections (median) | 9 | 10 | 10 | 9 |
| Proportion of instruments present from the start | 16% | 21% | 8% | 24% |
| Number of instruments entering midway | ★ 20 | 29 | 26 | 26 |
| Number of instruments exiting early | ★ 10 | 16 | 18 | 28 |
Three reliable readings：
- ★ Jazz's instrumentation is clearly smaller (22 vs 36) —— partly because it isrecorded live, with not as much overdubbing. This one can be borrowed: small instrumentation + everyone has something to do is the most valuable thing jazz can give to pop
- ★ Jazz also has the fewest entrance/exit events (20 in / 10 out) —— its variation does not rely on "changing instrumentation," but onchanges in what the same group of people plays
- hiphop-rnb has the most early exits (28) —— it is the most "subtractive" style
⚠ Unreliable reading: BPM. Detected jazz median is 117, range 74–162, but beat tracking has known octave errors on swing grooves.Do not cite this number.
8. Correspondence with ARR-SPEC fields
| Field | This skill |
|---|---|
meta.style_layer |
mc-style-jazz |
form[].harmony |
§3. ★ In jazz,harmony is the protagonist, and the degrees should be written out in full |
form[].bars |
★ §5——the meaning is "the length of one chorus" |
arrangement.roster |
§7——Target just over 20 tracks, not 36 |
groove.feel |
swing16 / shuffle |
render.*.style_prompt |
Write clearly which kind of jazz it is (§1①), do not just write jazz |
9. Must pass after writing
- It is clearly stated whichbranchof jazz it is, not a generic "jazz"
- §2 transplant table has been checked; techniques borrowed out of jazz are all in the "borrowable" column
- When bringing things into jazz, it has been checked whether they would break the premise that "someone is improvising"
- The harmony is written withscale-regionthinking, not just a chord sequence (§3.3)
- Instrumentationclearly smaller than pop(target just over 20, not 36)
- If there are improvised sections,
form[].barsthe meaning is clearly annotated - Comping leaves gaps,not filled in completely
- Changing dominant/diminished scale licks have not been brought into a pop song (unless a jazz flavor is deliberately wanted)
Appendix: Sources
- Mark Levine《The Jazz Theory Book》—— §3 all main content (chord–scale, avoid notes, melodic minor harmony and interchangeability, diminished scale, whole-tone scale).
- Valerio《Bebop》——§6。
- Fake Book——repertoire and head form.
- Jazz Guitar Groove——
CAGED, scale patterns, 4-note sequences, chromatic embellishment, triplet patterns.
★ This book was originally misclassified under
mc-rhythm-section, actually an improvised term, attributed to this skill andmc-melody。 - measured data: repository-measured corpus (10 jazz-acoustic tracks).
- Jazz harmony piano practice