# Jp Harmony Advanced

> Advanced harmony techniques - slash chords, secondary dominants, two-five progressions, ura-code (tritone substitution), subdominant minor borrowing, tension-note selection, cliché lines, passing diminished, sus4, blues. Use when the user wants chord progressions with more color or a jazzier feel, wants to reharmonize a progression, or asks how to use a specific harmonic technique.

- Skill: `jtydhr88/jp-harmony-advanced` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add jtydhr88/jp-harmony-advanced`
- Raw SKILL.md: https://api.skillmd.com/api/skills/jtydhr88/jp-harmony-advanced/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: jtydhr88 (https://skillmd.com/u/jtydhr88)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/jtydhr88/jp-harmony-advanced

---


# Japanese-Style Advanced Harmony Techniques (jp-harmony-advanced)

This skill is compiled from "初歩から身につく！コードの選び方マニュアル" (Sho Ueda), Chapters 3–4, and "もっと！思いどおりに作曲ができる本", Chapter 2.
All examples default to **Key=C** (minor examples default to C Minor / A Minor unless otherwise noted). All progressions are notated **both in letter names and Roman-numeral degrees**.
Large reference tables (full secondary-dominant table, full tension table, full passing-diminished table, etc.) are in [reference.md](reference.md) in this directory.

## Prerequisites at a Glance (30 seconds)

- Functions: T (トニック, tonic), S/SD (サブドミナント, subdominant), D (ドミナント, dominant). The minimal cadential unit is the カデンツ (cadence).
- Substitution principle: chords sharing most of their tones can stand in for each other. T = I / IIIm7 / VIm7; S = IV / IIm7; D = V7 / VIIm7(♭5) / IIIm7.
- **強進行 (kyō-shinkō, "strong progression")** = root motion up a perfect 4th (= one step counterclockwise on the circle of fifths), the root motion with the strongest forward drive; half of the techniques in this skill are built on it.
- **トライトーン (tritone)**: the augmented 4th formed by the 3rd and 7th of a dominant seventh chord — the source of tension and the urge to resolve (the theoretical basis of the ura-code / 裏コード, tritone substitution).

## Symptom → Technique Quick Lookup

| The user wants | First-choice techniques (section no.) |
|---|---|
| More drive / vividness | Secondary dominant (3), two-five (4) |
| Jazzier / more stylish | Tensions (9), chained two-fives (4), ura-code (5) |
| Wistfulness (切ない, setsunai), a passing shadow | Subdominant minor (6), IIIm7 (2) |
| Chromatic bass line | Slash chords (1), ura-code (5), passing diminished (11), cliché (10) |
| Same chord held too long, wants internal motion | Cliché (10), sus4 (8), pedal point (12) |
| Avoid the cliché feel of the plain dominant 7th | Dominant minor (7), ura-code (5), unresolved V7sus4 (8) |
| Melancholy / coolness / jamming | Blues and blue notes (13) |
| A wholesale change of atmosphere for a section | Modulation lead-ins (14) |
| Full reharmonization | Checklist (15) |

---

## 1. 分数コード (Bunsū Chord = Slash Chord)

**Principle**: change the lowest note of the chord (転回 = inversion, or directly specify the bass note); the chord skeleton stays intact while the bass line is freed up. Notation: C(onE) = C/E.
A triad has the root position plus 2 inversions; a seventh chord goes up to the 3rd inversion (G7 / G7(onB) / G7(onD) / G7(onF)).

**Degree formulas with Key=C examples**:

| Usage | Degrees | Key=C example |
|---|---|---|
| Chromatic ascending bass (with a secondary dominant) | IIm → II7(on♯4) → V | `Dm → D7(onF#) → G` (bass F→F♯→G) |
| Canon-type descending bass | I → V(on7) → VIm → IIIm(on5) → IV → I(on3) → IIm → V7 | `C → G7(onB) → Am → Em(onG) → F → C(onE) → Dm → G7` |
| Smoothing the bass line | I → V(on7) → VIm → I(on5) → IV → I(on3) → IIm7 → V7 | `C → G(onB) → Am → C(onG) → F → C(onE) → Dm7 → G7` (bass C-B-A-G-F-E-D-G, stepwise) |
| Softening the sonority (1st inversion → root position) | I → IV(on6) → IV | `C → F(onA) → F`, `G → C(onE) → C` |
| "Second inversion of I" decorating V | IV → I(on5) → V(7) | `F → C(onG) → G7` — C(onG)+G are analyzed together as a single D function |
| ペダルポイント (pedal point, sustained bass) | I → V(onI) → IV(onI) → IVm(onI) | `C → G(onC) → F(onC) → Fm(onC)` |

**Bass-line design examples** (read the slash notation and you get the bass line; all from the book's exercises):

| Progression | Bass line | Design intent |
|---|---|---|
| `D → Em7(onD) → A7(onC#) → D` | D-D-C♯-D | Hold → half step down → return |
| `C → C#dim7 → Dm → D#dim7 → Em` | C-C♯-D-D♯-E | Chromatic ascent (with passing diminished) |
| `G → D7(onF#) → G7(onF) → C(onE) → Cm(onEb)` | G-F♯-F-E-E♭ | Chromatic descent |
| `Csus4 → Csus4(onEb) → Csus4(onF) → Csus4(onAb)` | C-E♭-F-A♭ | Upper voices static, bass moves (reverse slash chord) |

**Typical use cases**: when large bass leaps sound clumsy; when you want a chromatic/stepwise bass line; when you want to soften or enrich the sonority without changing the chord skeleton. The pedal-point type actually produces the sound of complex tension chords, yet is much easier than voicing tension chords directly.

**Cautions**:
- The more I is inverted, the weaker the sense of finality (sometimes exactly the effect you want); overusing inversions muddies the sound — when unsure, keep root position.
- A soft sonority is not a cure-all: in a hard-edged song it gets in the way — 適材適所 (tekizai-tekisho, "the right tool in the right place").

---

## 2. IIIm7 — The Chameleon That Works as Both T and D

**Principle**: Em7 (E-G-B-D) shares 3 tones with C△7 → can substitute for I; shares 2 tones with G7 → can substitute for V7. In practice it is almost always used in its seventh-chord form, IIIm7.

**Degree formulas / Key=C examples**:
- Substituting for I (T): in the second pass of a repeated section, `C Am Dm G | Em7 Am Dm G` = `I VIm IIm V | IIIm7 VIm IIm V`, avoiding monotony.
- Substituting for V7 (D), often moving to VIm: `C△7 → Dm7 → Em7 → Am` = `I△7 → IIm7 → IIIm7(D) → VIm(T)` — one shade darker than using G7; common in ballads.
- In the canon progression IIIm(7) can also go to IV: `C G Am Em7 F C Dm G` = `I V VIm IIIm7 IV I IIm V`.

**Typical use cases**: adding 切なさ (setsunasa, wistfulness) and depth to a major-key progression; avoiding repeated appearances of I (e.g., Mr.Children's "HANABI" insists on IIIm7 in the chorus, never landing on I).

**Cautions**: forcing it in sounds bad — find spots where it "gets along" with the melody; the 9th on IIIm7 is usually avoided (see the tension section).

---

## 3. セカンダリードミナント (Secondary Dominant, abbreviated Sec.D)

**Principle**: "the V7 that a given chord would have if it were I." Placed immediately before the target chord (a temporary tonic), it forms a ドミナント・モーション (dominant motion, dominant resolution) toward it. Root motion up a 4th = 強進行 (strong progression), with built-in drive, and the accidentals create chromatic lines.

**Degree formulas (major)**: `VI7→IIm / VII7→IIIm / I7→IV / II7→V / III7→VIm`.
The II7 pointing to V has a special name: **ドッペルドミナント (Doppeldominante, double dominant)**. VIIm(♭5) is a diminished triad and can never be I, so no Sec.D points to it. See [reference.md](reference.md) for the full major/minor tables.

**Key=C examples**:
- Bland → vivid: `C Am F G` (I VIm IV V) → `C E7 Am C7 F D7 G` = `I III7 VIm I7 IV II7 V`.
- Dominant chain: `C A7 D7 G7` = `I VI7 II7 V7` (the target chord itself is Sec.D-ified in turn).
- Combined with inversion for a chromatic bass: `Dm(onF) → D7(onF#) → G` = `IIm(on♭3̂) → II7 → V`.

**Typical use cases**: when a progression is all diatonic and sounds bland, insert the Sec.D before any "chord that acts as a temporary T" and it is instantly refreshed; also the standard lead-in for modulation (place the target key's V7 at the entrance — see section 14).

**Cautions**:
- Almost always used in seventh-chord form (not as a triad); the target chord may also be seventh-ified (`C A7 Dm7 G7` = `I VI7 IIm7 V7`).
- Diminished/augmented triads (VIIm(♭5), IIm(♭5), ♭IIIaug, etc.) can never be I, so they have no corresponding Sec.D.
- Comprehensive exercise pattern: `C Am A7 Dm D7 G G7(onF) | E7 Am A7 Dm G7 Csus4 C` — Sec.D, slash chords, and sus4 mixed together.

---

## 4. ツーファイヴ (Two-Five, ii–V Progression)

**Principle**: IIm7→V7 fits together extremely well (強進行, strong progression); add I and you get the two-five-one: `Dm7 → G7 → C` = `IIm7 → V7 → I`. **Any dominant seventh (including a Sec.D) can be split at any time into its own two-five** — "when dad (V7) makes an appearance, big sister (IIm7) always comes along."

**Degree formula**: immediately before a Sec.D, insert "the IIm7 that would correspond if that chord were V7." Target is a major chord → use m7; target is a minor chord → use **m7(♭5)** per its minor key (in practice a plain m7 is also fine, and triads work too).

**Key=C examples**:
- Single spot: `C → Gm7 → C7 → F` = `I → Vm7 → I7 → IV` (Gm7-C7 is the two-five aiming at F; the sound is quite オシャレ (oshare, stylish)).
- Chained two-fives (full table in reference.md):
  `C Bm7(b5) E7 Em7(b5) A7 Am7 D7 Dm7 G7 C`
  = `I VIIm7(b5) III7 IIIm7(b5) VI7 VIm7 II7 IIm7 V7 I`
- Cross-key chain (jazz type): `F#m7 B7 Em7 A7 Dm7 G7 C△7` — these are the IIm7→V7 of three keys, E/D/C respectively, with the root moving by strong progression at every step.

**Dominant-7th → two-five conversion examples** (exercise patterns from the book):
- `C → E7 → Am → D7 → G` → `C → Bm7(b5) → E7 → Am → Am7(b5)? → D7 → G` (Bm7(♭5) split out of E7; in practice a plain m7 also works for the II)
- Jazz-style full passage: `F → Em7(b5) → A7 → Dm → G7 → Gm7 → C7 → F → D7 → Gm7 → C7sus4 → C7`
  = `I → VIIm7(b5) → III7 → VIm → II7 → IIm7 → V7 → I → VI7 → IIm7 → V7sus4 → V7` (Key=F)

**Typical use cases**: wanting a jazz flavor ("jazz begins with the two-five and ends with the two-five"); two-five-ifying a modulation lead-in (`…C → F#m7 → B7 ⇒ E△7`); when composing, imagining a two-five in advance and writing the melody over it often yields fresh lines. Build the habit of **checking every dominant seventh on the page for "can this be replaced with a two-five?"**.

**Cautions**: real songs are not wall-to-wall two-fives — **ピンポイント (pinpoint, precisely targeted use)** is best; there are also plenty of spots where it doesn't fit, so don't force it.

---

## 5. 裏コード (Ura-Code, Tritone Substitution)

**Principle**: G7 and D♭7 possess **exactly the same トライトーン (tritone)** (B–F = the 3rd and 7th of D♭7 with roles swapped), so they can substitute for each other. Two ways to find it: (1) the dominant seventh directly opposite on the circle of fifths; (2) "the dominant seventh a **half step above** the root of the target T chord" (= a diminished 5th away from the original dominant's root).

**Degree formula**: `V7 → ♭II7` (applies to any dominant seventh, including Sec.D). After substitution the bass becomes a **chromatic descent into the target**: `IIm7 → ♭II7 → I`.

**Key=C examples**:
- Basic: `Dm7 → G7 → C△7` → `Dm7 → D♭7 → C△7` = `IIm7 → ♭II7 → I△7` (bass II→♭II→I, a gorgeous chromatic descent).
- Full ura-substitution of a chain: `F#m7(b5) B7 Em7 A7 Dm7 G7 C△7` → `F#m7(b5) F7 Em7 E♭7 Dm7 D♭7 C△7(9)` — the bass descends chromatically at every step.
- Ura-ifying a Sec.D: `Em7 A7 Dm7 G7 C△7` → `Em7 E♭7 Dm7 D♭7 C△7` = `IIIm7 ♭III7 IIm7 ♭II7 I△7` (the roots "transform into a chromatic slide!" — 半音スライドに変身).
- Compound techniques (the ura's own two-five): an ura-code can itself be two-five-ified, and **the split-out chords of the front (表, omote) and back (裏, ura) sides can be freely recombined**: `C → B♭m7(13) → E♭7 → Dm7` (E♭7, the ura of A7, two-five-ified); `Fm7 → E7(♭9) → Am7` (the IIm7 of ura-B♭7 = Fm7, plus the omote V7 = E7).

**Typical use cases**: wherever a dominant seventh appears and you want a stronger jolt or a chromatic bass line, try the swap; creates the "suave, mature," "deep" jazz cadence.

**Cautions**: if after the swap it feels "somehow off," changing it to a **♭5 chord** (D♭7 → D♭7(♭5)) usually fixes it; in descending lines notate with flats (D♭7, not C♯7).

---

## 6. サブドミナントマイナー (Subdominant Minor, S.M)

**Principle**: borrow subdominant-function chords from the **同主調 (dōshu-chō, parallel key — same tonic: C Major ↔ C Minor)**. Such imported chords are collectively called **借用和音 (shakuyō waon, borrowed chords)**; Japanese theory also calls them **準固有和音 (jun-koyū waon, quasi-diatonic chords)**. They inject 切なさ (setsunasa, wistfulness) into a major-key melody.

**Degree formulas**: the two S members IV and IIm become minor-key versions → **IVm (IVm7)** and **IIm(♭5) (IIm7(♭5))**. Substitute group overview (common trait: all contain the minor characteristic tone ♭6̂, which in Key=C is the note A♭):

| Chord | Degrees | Key=C |
|---|---|---|
| S.M proper | IVm(7/6), IIm7(♭5) | Fm / Fm7 / Fm6, Dm7(♭5) |
| Substitute | ♭VI△7 | A♭△7 |
| Substitute | ♭VII7 | B♭7 (the 7th is sometimes omitted) |
| Substitute | ♭II△7 | D♭△7 |

**Key=C examples**:
- The classic S→S.M: `C → F → Fm → G` = `I → IV → IVm → V`; `F → Fm6 → C` = `IV → IVm6 → I` (**the S.M frequently takes an added 6th**).
- The rarer reversed order S.M→S: `C → Dm(♭5) → Dm → G` = `I → IIm(♭5) → IIm → V` (almost never in classical practice, occasionally in pop).
- Using the substitutes: `F → A♭△7 → B♭ → C` = `IV → ♭VI△7 → ♭VII → I` — an extremely common progression when returning to T.

**Typical use cases**: when the melody contains the ♭6̂ note (A♭ in Key=C); when a major-key chorus should momentarily have "a shadow flit across a gap in the clouds"; the IV→IVm→I before an ending.

**Cautions**: S.M and ordinary S may be used side by side; reach for the ♭VI/♭VII substitutes only when you want an even more "roundabout" color. See [reference.md](reference.md) for the complete substitute table.

---

## 7. 旋法のテイスト (Modal Flavors: The Dorian IV / Dominant Minor)

**Principle**: a モード (mode) = "a state of order established on a certain scale with a certain note as its center"; a 音階 (scale) is merely the ladder-like arrangement of notes itself. The seven medieval church modes (shown by white-key starting notes; all transposable):

| Mode | White-key start | Notes |
|---|---|---|
| イオニア Ionian | C | Later developed into the major key |
| ドリア Dorian | D | Like natural minor, but the IV chord is major |
| フリギア Phrygian | E | |
| リディア Lydian | F | |
| ミクソリディア Mixolydian | G | |
| エオリア Aeolian | A | Later developed into the minor key (natural minor) |
| ロクリア Locrian | B | |

The two most practical harmonization tricks:

**(1) ドリアのIV (the Dorian IV)** — borrowing the major-triad IV inside a minor key:
- Degrees: `Im → IV → V → Im` (natural minor would normally give IVm)
- Key=Cm: `Cm → F → G → Cm` = `Im → IV(☆Dorian) → V → Im`

**(2) ドミナントマイナー (dominant minor, Vm7)** — minorizing the D function to dodge the 当たり前感 (atarimae-kan, "predictable/cliché feel") of the plain dominant seventh:
- Degrees: `Im → IVm → Vm7 → Im`
- Key=Cm: `Cm → Fm → Gm7 → Cm` = `Im → IVm → Vm7(☆) → Im`
- The IIIm7→VIm inside a major key can also be interpreted, from the relative-key perspective, as a dominant minor.

**Typical use cases**: harmonizing in minor when you want the polished feel of folk/Celtic/city pop; `Dm → G → Am7 → Dm` (Dorian home turf: G = the Dorian IV, Am7 = the dominant minor).

**Cautions**: usually let just **one spot** waft the Dorian scent — a light touch is enough.

---

## 8. sus4 — Suspension and Resolution

**Principle**: hoist the 3rd up to the perfect 4th (sus = suspended). The suspended note usually then falls back to the 3rd = **resolution**, producing the reassurance of "returning home." Usable on T, S, and D alike.

**Degree formulas / Key=C examples**:

| Usage | Degrees | Key=C |
|---|---|---|
| Two-stage cadence (prolonging tension) | I(on5) → V7 → Isus4 → I | `C(onG) → G7 → Csus4 → C` |
| Decoration inside D | Vsus4 → V7 | `Gsus4 → G7` (stitching the melody's C→B fall) |
| Use on S | I → IIm7sus4 → IIm7 | `C → Dm7sus4 → Dm7` |
| Unresolved, straight to T (common in recent pop) | I → V7sus4 → I | `C → G7sus4 → C` |
| 掛留音 (keiryū-on, suspension/retained note) type | IIm7 → V7sus4 → V7 | `Dm7 → G7sus4 → G7` (the 7th of Dm7, C, is held over, then falls to B) |

**Typical use cases**: avoiding "deflating on beat 1" at phrase endings; オブリガート (obbligato) material — the 4→3 fall of sus4 is itself a lovely fill phrase.

**Comprehensive example** (model exercise pattern from the book, Key=C):
`C F△7 G7 Am F C(onE) Dm7 G7sus4 G7 | C F△7 G7 Am Dm7 G7 Csus4 C`
= `I IV△7 V7 VIm IV I(on3) IIm7 V7sus4 V7 | I IV△7 V7 VIm IIm7 V7 Isus4 I`

**Cautions**: when the sus4 sounds only for an instant it is **usually not written** on the chart (the momentary G7sus4 inside `Dm → G7` is simply written G7); when important it may be written even if brief — no absolute rule; no need to use it a lot, place it only where it fits.

---

## 9. テンション (Tension Notes)

**Principle**: stacking further thirds above the chord's 7th yields the 9th/11th/13th — **7 kinds** in all: ♭9, ♮9, ♯9 / ♮11, ♯11 / ♭13, ♮13. A tension note = "a note that heightens tension and makes you want to move into a stable sonority" — the source of the jazz sound.

**Common tensions per chord type (quick reference)**:

| Chord type | Common tensions |
|---|---|
| △7 (major-7th family) | 9, ♯11, 13 |
| m7 | 9, 11, 13 |
| m7(♭5) | 9, 11, ♭13 |
| Dominant 7th (V7 etc.) | **♮9, ♭9, ♯9, ♯11, ♮13, ♭13 — all of them**, chosen per situation |

**9th usage essentials (minimal avoid-note / アヴォイドノート rules)**:
1. On △7, m7, and most chords, use ♮9.
2. Only the dominant-7th family may use all of ♮9/♭9/♯9; **when the destination T is a minor chord, ♮9 is almost never used** (use ♭9 etc. instead).
3. **On the m7(♭5) family and on IIIm7, the 9th is usually avoided**.

**Key=C examples**:
- Jazzing up a two-five-one: `Dm7 G7 C` → `Dm7(9) → G7(13,9) → C△7(13,9)` = `IIm7(9) → V7(13,9) → I△7(13,9)`.
- Minor-chord destination: `C△7(9) → E7(♭13,♭9) → Am7(9)` = `I△7 → III7 → VIm7` (E7 heads to Am, hence ♭9/♭13).
- The 11th in the melody layer (a key to hit songs): **on minor chords use ♮11** (m3 and 11 are a whole step apart — no clash); **on major chords use ♯11** (dodging the half-step collision with the 3rd; ♯11 clashes by half step with the 5th, so **the 5th is usually omitted**). Example: `Am7(11) → G7sus4 → G7 → F△7(#11)`.

**Typical use cases**: wanting a jazz/city-pop texture; harmonizing under a sustained top note (letting the held note be reinterpreted as a tension of each passing chord — see section 12).

**Cautions**: tensions are **written in parentheses to the right of the chord name**, and are also frequently omitted entirely for chart cleanliness; usages outside the rules are valid as long as the ear approves — the strict avoid-note rules differ per degree and need not all be memorized. See [reference.md](reference.md) for full per-progression voicing examples.

---

## 10. クリシェ (Cliché, Chromatic Line Technique)

**Principle**: **part** of the chord's tones slides by half step (or whole step) while **the remaining tones hold still**. The sliding voice can be anywhere: the lowest voice (most common), an inner voice, or the トップ・ノート (top note). One of its charms: the **augmented triad (aug)**, normally hard to use on its own, can enter naturally as part of the line (in classical music aug = the sound of 憧れ, akogare, "yearning").

**Key=C / Am examples**:
- Descending type: `Am → G#aug → C(onG) → F#m7(b5) → F△7` (bass A→G♯→G→F♯→F) = `VIm → …chromatic line…→ IV△7`
- 5th-ascending type: `G → Gaug → Em(onG) → G7` (inner voice D→D♯→E→F; the 007-theme type)
- Top-note ascent: `C → Caug → C6 → C7` (top note G→G♯→A→B♭)
- Minor riff type: `Am → Am△7(onA♭) → Am7(onG) → Am△7(onA♭)` (a Latin staple; bass A→A♭→G→A♭)
- Lowest-voice descent: `C → C△7 → C7 → A7 → Dm → Dm△7 → Dm7 → G`

**How to fit the melody (three composer's strategies)**:
1. **Weave the sliding line itself into the melody** ("Someday My Prince Will Come" type) — the most direct effect;
2. **Repeat the same melodic figure on the common tones** while the background harmony slides, creating the impression (Kaela Kimura "BUTTERFLY" type);
3. **The melody ignores the cliché entirely** — the line becomes a 隠し味 (kakushi-aji, hidden seasoning), the most sophisticated approach (Dreams Come True "やさしいキスをして" type).

**Completion examples (model answers from the book; the line is not unique)**:
1. `Am → G#aug → Am7(onG) → D7(onF#)` — bass A→G♯→G→F♯, chromatic descent
2. `D → Daug → Bm(onD) → D7` — inner voice A→A♯→B→C, chromatic ascent
3. `Fm → D♭(onF) → Dm(♭5) → D♭(onF) → Fm` — inner voice C→D♭→D→D♭→C, up-and-back
4. `Gm → G♭aug → B♭(onF) → C7(onE) → E♭6 → Gm(onD) → C#dim7 → D` — long-range chromatic descent G→G♭→F→E→E♭→D→C♯→D

**Typical use cases**: when the same chord persists too long and gets boring; adding 色気 (iroke, allure) to an "unassuming phrase"; intro/interlude riffs.

**Cautions**: **don't discuss cadence theory mid-cliché** — the cadence restarts from the chord after the line ends; it is normal for the constituent tones to "splinter" along the way, so don't over-analyze; big top-note motion grabs the ear, small inner-voice motion sounds mature.

---

## 11. パッシングディミニッシュ (Passing Diminished)

**Principle**: **insert a dim7 between two chords a major 2nd apart** — the bass becomes chromatic and the progression is smoothed, and "a surge of poignant feeling wells up."

**Degree formulas (with Key=C)**:

| Direction | Degrees | Key=C |
|---|---|---|
| Ascending | I → ♯Idim7 → IIm7 | `C → C#dim7 → Dm7` |
| Ascending | IIm7 → ♯IIdim7 → IIIm7 | `Dm7 → D#dim7 → Em7` |
| Ascending | IV△7 → ♯IVdim7 → V7 | `F△7 → F#dim7 → G7` |
| Ascending | V7 → ♯Vdim7 → VIm7 | `G7 → G#dim7 → Am7` |
| Descending | IIIm7 → ♭IIIdim7 → IIm7 | `Em7 → E♭dim7 → Dm7` |
| Descending | VIm7 → ♭VIdim7 → V7 | `Am7 → A♭dim7 → G7` |

**Typical use cases**: delicate emotional build-ups, グッとくる (gutto-kuru, heart-gripping) wistful passages; chromatic bass design (`C C#dim7 Dm D#dim7 Em` climbing all the way up).

**Cautions**: insert only across major-2nd gaps; ascending offers ♯I/♯II/♯IV/♯V and descending ♭III/♭VI — those 6 positions and no more.

---

## 12. 保続音 (Hozoku-on, Pedal Point / Sustained Tone)

**Principle**: sustain a single note regardless of the chord changes. A bass pedal = the European church-music tradition, a **holy (ホーリー)** sonority; a top-voice pedal = an advanced technique.

**Key=C examples**:
- Bass pedal (dominant/tonic pedal): `C → Fm(onC) → C → Fdim7(onC) → C → Ddim7(onC) → C` — the bass C fixed throughout.
- Slash-chord style: `C → G(onC) → F(onC) → Fm(onC)` = `I → V(onI) → IV(onI) → IVm(onI)`.
- **Top-note pedal**: `C → Am7 → Dm7(11) → G7 → Em7 → A7 → Dm7(11) → G7` — the top G held throughout (G = the 5th of C, the 7th of Am7, the 11th of Dm7, the root of G7…).

**Typical use cases**: オブリガート (obbligato) material — behind a デッドスポット (dead spot, where the melody holds a long note) keep the bass fixed while upper chords slide; building tension before a chorus (dominant pedal); chant-like or floating passages.

**Cautions**: the trick to the top-note pedal — **arrange the voicings so that the held note, tensions included, can be interpreted as a chord-related tone over every chord**.

**Extension — the interface between オブリガート (obbligato) and harmonic technique**: when inserting a responding phrase into a デッドスポット (dead spot, where the melody sustains or rests), this skill's materials apply directly:
- the 4→3 resolution fall of sus4 (`C → F → Gsus4 → G`);
- non-chord tones approaching a chord tone from a half step below (A♯→B, C♯→D — exploiting the "urge to return");
- chords sliding over a pedal tone (`C(onG) → G → Am7(onG) → G → C(onG) → G7`);
- pentatonic runs: over major-triad-family chords use the major pentatonic (ヨナ抜き, yona-nuki, "omit 4 and 7": C D E G A); over minor-triad-family chords use the minor pentatonic (ニロ抜き, niro-nuki, "omit 2 and 6": A C D E G).

---

## 13. ブルース／ブルーノート (Blues / Blue Note)

**Principle**: **blue notes (ブルーノート)** = the 3rd, 5th, and 7th of the major scale each lowered a half step (♭3, ♭5, ♭7) — the source of the "blue" (melancholy) sound; embed them back into the major scale and you get the blue-note scale, along which both melody and improvisation (アドリブ, ad-lib) travel.
**スリー・コード (three-chord progression)**: only the three chords T/SD/D, **all turned into dominant 7ths** — dominant-seventh instability blankets the whole tune, so it pushes forward without ever coming to rest; this "perpetual instability" is precisely the source of the blues' mournful character.

**Basic 12 bars (degrees / Key=C)**:

```
| I7  | I7  | I7 | I7 |        | C7 | C7 | C7 | C7 |
| IV7 | IV7 | I7 | I7 |   ＝   | F7 | F7 | C7 | C7 |
| V7  | IV7 | I7 | V7 |        | G7 | F7 | C7 | G7 |
```

The final line's **V7 → IV7 → I7** is the blues-specific cadence (adopted by countless songs, e.g. the Beatles' "Let It Be").

**ジャズ・ブルース (jazz blues)** (subdivided version, Key=C) — the grand synthesis of this skill's techniques:

```
| C7 (I7)    | F7 (IV7)       | C7 (I7)       | Gm7 C7 (Vm7 I7)    |
| F7 (IV7)   | F#dim (#IVdim) | C7 (I7)       | Em7 A7 (IIIm7 VI7) |
| Dm7 (IIm7) | G7 (V7)        | C7 A7 (I7 VI7)| Dm7 G7 (IIm7 V7)   |
```

Wherein: Gm7-C7 = the two-five aiming at IV7; F♯dim = passing diminished; Em7-A7 and Dm7-G7 = two-five turnarounds (ターンアラウンド). In jazz these get further subdivided, tritone-substituted, and swapped for substitutes.

**Typical use cases**: adding a "cool" melancholy tinge to a melody/solo (a sprinkle of ♭3, ♭7 suffices — the whole song needn't be blues); the universal common language of jam sessions.

**Cautions**: **the "one cycle = 12 bars" rule almost never changes** — however much jazz subdivides, ura-substitutes, and re-substitutes, the skeleton stays put.

---

## 14. Synthesis: Harmonic Lead-Ins for 転調 (Modulation)

**Principle**: the most beautiful combined stage for Sec.D, the two-five, and the ura-code is modulation — **place the new key's dominant seventh immediately before its entrance (= the lead-in, like a polite greeting before borrowing something)** and you can slide smoothly into any key. 転調 (tenchō, modulation) = changing the key of part of a song; 移調 (ichō, transposition) = shifting the whole song up or down — do not confuse the two.

**Seven lead-in methods (all departing from `Dm7 → G7 → C` = IIm7→V7→I in Key=C)**:

| Method | Progression | Explanation |
|---|---|---|
| Dominant-7th lead-in | `…C → A♭7 ⇒ D♭` | The V7 of target key D♭ placed before the entrance |
| Same method, minor target | `…C → D#7 ⇒ G#m` | D♯7, the dominant 7th of target G♯m |
| Two-five-ified lead-in | `…C → F#m7 → B7 ⇒ E△7` | The target key's IIm7→V7→I; the strong-progression chain is even smoother |
| Lead-in dominant → ura-substituted | `…C → … → B7 ⇒ B♭` | The V7 of target B♭ = F7; use its ura-code, B7 |
| Ura-code further two-five-ified | `…C → Cm7(9) → B7(#11) ⇒ B♭△7` | The IIm7 split from F7's two-five (Cm7) + the ura B7 (an "ウルトラC," ultra-C stunt) |
| Omitting the pre-modulation T | `Dm7 → G7 → A♭7 ⇒ D♭` | Skip landing on C and go straight to the lead-in — changing the subject mid-sentence, greater impact |
| 突然転調 (sudden modulation) | `Dm7 → G7(13) → A△7…` | No lead-in at all, maximum impact; often paired with a ブレイク (break, silence) or a rhythmic cutoff |

**Key proximity**: the 平行調 (heikō-chō, relative key — C⇄Am, same key signature) and the 同主調 (dōshu-chō, parallel key — C⇄Cm, same tonic) are the most natural to travel between; C→E♭ (the relative key of Cm) is also common; **a half-step up/down modulation changes 5 accidentals in the key signature at once**, and the half-step-up final chorus is the staple climax device (`Dm7 → G7 → D#m7 → G#7 ⇒ C#` = two-five-ifying the lead-in to the new key).

**Cautions**: after modulating you need not start from T — **patterns starting from IIm7 or IV△7 are also plentiful**; mind the melody above, and experiment within what doesn't strain it.

---

## 15. Reharmonization Field Checklist

Given a bland progression, try in order (at every step the ear is the final judge):

1. **Seventh-ify** (triads → 7ths; not everywhere — watch the overall balance)
2. **Substitute swaps**: I ⇄ IIIm7/VIm7, IV ⇄ IIm7, V7 ⇄ VIIm7(♭5)/IIIm7
3. **Insert Sec.D**: before every "chord acting as a temporary T," try placing its V7
4. **Two-five-ify dominants**: check every dominant 7th for splitting into IIm7→V7
5. **Ura-substitute dominants**: for a chromatic bass / extra bite, V7 → ♭II7 (if it doesn't fit, add ♭5)
6. **Borrow S.M**: IV→IVm(6), or the ♭VI△7/♭VII7 substitutes, for wistfulness
7. **Insert dim7 across major-2nd gaps**, **slash chords for smooth bass lines**, **sus4 for delayed resolution**
8. **Sprinkle tensions**: voice 9/11/13 per the tables in section 9
9. Finally ask yourself: **is it overdone?** — "never over-subdivide the chords"; straight-ahead rock/pop especially must guard against verbosity; there are equally cases where simple is best.

**Step-by-step upgrade demo** (same skeleton `C → Am → Dm → G` = `I → VIm → IIm → V`, the cyclic progression):

| Step | Progression | What was used |
|---|---|---|
| Original | `C → Am → Dm → G` | Diatonic triads |
| Seventh-ified | `C△7 → Am7 → Dm7 → G7` | Step 1 |
| Sec.D inserted | `C E7 Am C7 F D7 G` = `I III7 VIm I7 IV II7 V` | Step 3 |
| Two-five-ified | `C → Bm7(b5) → E7 → Am → Em7(b5) → A7 → Dm7 → G7` | Step 4 |
| Ura + tensions | `Em7 → E♭7 → Dm7 → D♭7 → C△7(9)` | Steps 5+8 (chromatic bass descent to close) |
| Wistfulness added | `C → Am → Fm6 → G7sus4 → G7` | Steps 6+7 (S.M + sus4) |

---

## Terminology Quick Reference (Japanese → English)

| Japanese | English |
|---|---|
| 分数コード／転回形 | Slash chord / inversion |
| セカンダリードミナント（Sec.D） | Secondary dominant |
| ドッペルドミナント | Double dominant (Doppeldominante, II7) |
| ツーファイヴ（ワン） | Two-five(-one) progression (ii–V(–I)) |
| 裏コード | Ura-code (tritone substitution) |
| サブドミナントマイナー（S.M）／準固有和音 | Subdominant minor (borrowed) / quasi-diatonic chord |
| 同主調／平行調 | Parallel key (same tonic) / relative key (same signature) |
| ドリアのIV／ドミナントマイナー | Dorian major IV / dominant minor (Vm7) |
| テンション／アヴォイドノート | Tension note / avoid note |
| クリシェ | Cliché (chromatic line technique) |
| パッシングディミニッシュ | Passing diminished chord |
| 保続音／ペダルポイント | Sustained tone / pedal point |
| 掛留音（けいりゅうおん） | Suspension (retained note) |
| 強進行／弱進行 | Strong progression (root up a perfect 4th) / weak progression (3rd motion) |
| トライトーン | Tritone (augmented 4th) |
| ブルーノート | Blue note (♭3, ♭5, ♭7) |
| オブリガート／デッドスポット | Obbligato (countermelody) / dead spot (long melody note) |
| ペンタトニック／ヨナ抜き／ニロ抜き | Pentatonic / yona-nuki (major pentatonic, "omit 4 & 7") / niro-nuki (minor pentatonic, "omit 2 & 6") |
| 転調（モジュレーション）／移調 | Modulation (key change within a song) / transposition (whole-song shift) |
| 突然転調／ブレイク | Sudden modulation (no lead-in) / break (silence/cutoff) |
| ターンアラウンド | Turnaround (section-ending two-five etc. pulling back to the top) |
| 循環コード／逆循環コード | Cyclic progression (I-VIm-IIm-V) / reverse cyclic (IIm-V-I-VIm) |
| 切ない／色気／オシャレ | Setsunai (wistful) / iroke (allure, savor) / oshare (stylish) |
| 適材適所／ピンポイント | The right tool in the right place / pinpoint (precisely targeted) use |