Methodology source: Sho Ueda, Shoho kara Mi ni Tsuku! Chord no Erabikata Manual ("Learn from the Basics! A Manual for Choosing Chords", Rittor Music), Introduction through Chapter 2. Core idea: harmonizing a melody is like a jigsaw puzzle (パズル) — a melody never has only one valid harmonization, but "knowledge" is the driving force that gets you closer to the right answer.
Workflow Overview
Given a melody, work through the following steps in order:
- Identify the key — the biggest shortcut to harmonization
- List the diatonic chords (ダイアトニックコード) — this immediately narrows the candidate pool
- Arrange them by cadence (ケーデンス) — match melody notes measure by measure, fitting them into the T→S→D→T framework
- Handle non-chord tones (非和声音) — decide which melody notes are "decoration" and confirm each one resolves
- Substitute / apply staple progressions — replace I with IIIm, IIm with IV, or drop in one of the three staple progressions directly
- Upgrade to 7ths — function unchanged, sound more stylish (オシャレ)
Simplifying assumption (beginner default): one chord per measure; once fluent, two per measure is fine.
Step 1: Identify the Key
1-1 Reasoning from Accidentals
Memorize the two orders in which accidentals are added (key-signature rules):
- Order of ♯s: ファ→ド→ソ→レ→ラ→ミ→シ (F → C → G → D → A → E → B)
- Order of ♭s: シ→ミ→ラ→レ→ソ→ド→ファ (B → E → A → D → G → C → F — exactly the ♯ order reversed)
Reasoning procedure:
- Tally the ♯/♭ notes in the melody and compare against the orders above. Example: only F♯ and C♯ appear, G carries no ♯ → most likely a key with 2 sharps.
- Each key signature maps to a pair of relative keys (平行調, relative major/minor) as candidates. 2♯ → D Major or B Minor.
- The key to telling major from minor: the minor scale's 7th degree — the leading tone (導音) — is frequently raised a semitone by accidental (a consequence of the harmonic minor scale).
- B Minor's leading tone is A♯: if A is never raised in the melody → conclude D Major.
- If the melody frequently shows "an accidental sharp outside the key signature that happens to be some minor key's leading tone" → interpret it as that minor key.
1-2 Distinguishing "Scale Tones" from "Ornamental Notes"
Accidentals (変化記号) in a melody come in two identities:
- 音階固有音 (notes inherent to the key's scale): the sharps/flats the scale itself carries
- 装飾音 (ornamental notes): temporary decoration, unrelated to the key
Note-by-note elimination rules:
| Observation | Judgment |
|---|---|
| The same note appears both with and without a ♯ | The ♯ version is very likely just decoration; the true note is ♮ |
| A note carries a ♯, but notes that should carry ♯ earlier in the ♯ order do not | That ♯ is unlikely to be a scale tone (e.g., ラ♯ appears but no ソ♯/レ♯ → ラ♯ is decoration) |
| A ♭ note sits right next to the same note as ♮, apparently setting up a descent | Ornamental note |
| Accidentals remaining after elimination | Assume they are scale tones, match them against the key-signature table to name the key, then use the leading-tone test to pick major vs minor |
Worked note-by-note example (♯s appear on ラ, ド, ファ; ♭ appears only on ミ):
- ド: both C♯ and C♮ occur → C♯ is very likely just decoration → the true note is C♮;
- ラ♯: if it were a scale tone, then by the ♯ order G and D would also have to be sharped, and they are not → ornamental; the true note is A♮;
- ミ♭: an E♮ sits adjacent, and it appears to set up a descent to D → ornamental;
- ファ♯: cannot be eliminated directly → assume it is a scale tone: "a key where C is ♮ and F carries a ♯" = G Major or E Minor;
- Leading-tone test: E Minor's leading tone is D♯, which should appear frequently; the score has none → conclude G Major.
1-3 Key Identification Is Inherently Ambiguous
The same melody may admit two legitimate readings (e.g., C Major with C→G→C, or A Minor with Am→E7→Am). In that case, decide from context and the mood (ムード) of the whole piece. Beyond theoretical deduction, the intuition of "feeling" the key from the melody matters most — play it and sing it before reasoning.
Key Signature Quick Reference
| 调号 | 大调 | 小调（平行短調） | 调号 | 大调 | 小调 | |
|---|---|---|---|---|---|---|
| 无 | C | Am | 1♭ | F | Dm | |
| 1♯ | G | Em | 2♭ | B♭ | Gm | |
| 2♯ | D | Bm | 3♭ | E♭ | Cm | |
| 3♯ | A | F♯m | 4♭ | A♭ | Fm | |
| 4♯ | E | C♯m | 5♭ | D♭ | B♭m | |
| 5♯ | B | G♯m | 6♭ | G♭ | E♭m | |
| 6♯ | F♯ | D♯m | 7♭ | C♭ | A♭m |
Step 2: List the Diatonic Chords (ダイアトニックコード)
Chain of logic: key determined → diatonic chords can be listed → candidate chords are fixed. Diatonic chords = chords built by stacking thirds on each scale degree, using only notes within that key's scale.
Major-Key Diatonic Chords (C Major as example)
| 级数 | I | IIm | IIIm | IV | V | VIm | VIIm(♭5) |
|---|---|---|---|---|---|---|---|
| C 大调 | C | Dm | Em | F | G | Am | Bm(♭5) |
| 功能 | T | S | ※变色龙 | S | D | T | D |
Transpose by degree to any major key, e.g. F Major: F(I)–Gm(IIm)–Am(IIIm)–B♭(IV)–C(V)–Dm(VIm)–Em(♭5)(VIIm(♭5)).
In practice, master these 5 first: I, IIm, IV, V, VIm.
- IIIm is a "chameleon chord that changes its role by context" — skip it at the beginner stage;
- VIIm(♭5) is rarely used as D; for the dominant function, prefer V.
Chord Construction Rules (in Semitones)
Interval quick reference (semitones between two notes):
| 音程 | 半音数 | 音程 | 半音数 |
|---|---|---|---|
| 短2度 | 1 | 完全5度 | 7 |
| 長2度（全音） | 2 | 短6度 | 8 |
| 短3度 | 3 | 長6度 | 9 |
| 長3度 | 4 | 短7度 | 10 |
| 完全4度 | 5 | 長7度 | 11 |
| 増4度/減5度 | 6 | 完全8度 | 12 |
The four triads (トライアドコード, triad chords; semitones stacked upward from the Root):
| 和弦 | 结构（下+上三度） | 半音数 | Root–5音 | 例（C 系） |
|---|---|---|---|---|
| Major | 長3 + 短3 | 4+3 | 完全5度 | C = C E G |
| Minor（m） | 短3 + 長3 | 3+4 | 完全5度 | Cm = C E♭ G |
| m(♭5)／dim | 短3 + 短3 | 3+3 | 減5度 | Cm(♭5) = C E♭ G♭ |
| aug | 長3 + 長3 | 4+4 | 増5度 | Caug = C E G♯ |
Principal 7th chords (triad + 7th; parentheses give semitones from Root to the 7th):
| 和弦 | 结构 | 半音数 | 例 | Notes |
|---|---|---|---|---|
| △7（Major 7th） | major triad + 長7度 | 4+3+4（11） | C△7 = C E G B | Also written CM7; a distinctly stylish sound |
| 7（dominant 7th, ドミナントセブンス） | major triad + 短7度 | 4+3+3（10） | C7 = C E G B♭ | Most frequently used; the 3rd–7th form a 減5度 (tritone), the source of its tension |
| m7 | minor triad + 短7度 | 3+4+3（10） | Cm7 = C E♭ G B♭ | More delicate than a plain minor triad |
| m7(♭5) | dim triad + 短7度 | 3+3+4（10） | Cm7(♭5) = C E♭ G♭ B♭ | Also called half-diminished (ハーフディミニッシュ, ∅); common in minor keys |
| dim7 | dim triad + 減7度 | 3+3+3（9） | Cdim7 = C E♭ G♭ B♭♭ | Contains two 減5度 intervals; extremely distinctive character |
| 6 | major triad + 長6度 | 4+3+2（9） | C6 = C E G A | Commonly used; m6 works the same way |
Fast method for building any chord (E♭ as example): first fix the outer frame — a perfect 5th above the Root (E♭→B♭, 7 semitones, never wrong) — then fill the inside: 4-below/3-above for Major, 3-below/4-above for Minor.
Supplementary general rules:
- If the constituent notes match, the symbol stays the same regardless of how open the voicing is or whether notes are doubled.
- 転回形 (inversion): when the Root is not the lowest note, write C(onG) or C/G (read "C on G"); inversion does not change the Root.
- A chord symbol is only a rough representative of "the harmony governing this passage" — notes outside the symbol sounding on the page is perfectly normal (those are non-chord tones; see Step 4).
Degree Name (ディグリーネーム) Notation Rules
This skill uses dual notation throughout — "letter + degree" — with degree rules as follows:
- The Roman numeral indicates "which scale degree of the current key the chord's Root sits on"; the quality suffix carries over as-is: Dm→IIm, G7→V7, C△7→I△7;
- Non-diatonic chords are labeled by the Root's alteration relative to the scale tone: C♯dim7 in C Major → ♯Idim7;
- Change the key and the degree changes: the chord C is I in C Major but IV in G Major;
- Minor-key degrees are referenced to the relative major: A♭ in C Minor → ♭VI.
Step 3: Arrange by Cadence (ケーデンス)
The "grammar" of chord ordering is called ケーデンス (cadence; the German-derived term is カデンツ).
The Three Functions
| Function | Japanese | Character | Members |
|---|---|---|---|
| T（Tonic） | トニック (tonic function) | Stable | I, VIm (VIm is I's "body double / stand-in") |
| S（Sub Dominant） | サブドミナント (subdominant function) | Mildly unstable, propels toward D | IIm, IV |
| D（Dominant） | ドミナント (dominant function) | Unstable, wants to return to T | V, VIIm(♭5) (V is overwhelmingly more common) |
D's instability must "resolve" onto T; this psychological need is precisely the source of musical forward momentum. IIIm is excluded from this list (chameleon).
The Three Cadence Types
- T → D → T: like "stand up, bow, sit down" — simple and forceful. Examples: C→G→C (I→V→I), Am→G→C (VIm→V→I)
- T → S → D → T: tension rises gradually, then resolves onto T in one stroke — the most "satisfying". Examples: C→F→G→C (I→IV→V→I), Am→Dm→G→C (VIm→IIm→V→I)
- T → S → T: returns to T without passing through D; S→T is usually IV→I, commonly called the アーメン終止 (Amen cadence / plagal cadence). Example: C→F→C (I→IV→I)
同機能の連用 (consecutive use of same-function chords): chords of the same function may be chained. Example: C→Am→F→Dm→G→C (I→VIm→IV→IIm→V→I) — I+VIm chained as T, IV+IIm chained as S; the whole is still T→S→D→T.
Measure-by-Measure Harmonization Procedure
- Confirm the essentials: write out the key's I, IIm, IV, V, VIm with their functions, plus the three cadence types.
- List candidates per measure: take that measure's melody notes and find the diatonic chords whose constituent notes contain them.
- Melody notes exactly match a chord's tones → direct candidate (e.g., measure notes A·F·C → F);
- Multiple chords contain the notes → parallel candidates (e.g., B♭·D → B♭ or Gm, both S).
- Adjudicate by cadence: if the first three measures already form T→S→D, measure four should return to T — pick the T-function candidate (F or Dm both work; choose by taste).
- Ending rule: closing the piece on the most stable chord, I, is best.
- T is both endpoint and starting point: in a function chain like T S D T S T D T, one T is often shared by the cadence before and the cadence after it.
Worked Example: F Major, 3/4 Time, 8 Measures
First write out the candidate table: F(I,T), Gm(IIm,S), B♭(IV,S), C(V,D), Dm(VIm,T). Then measure by measure:
| 小节 | 旋律音 | Candidates containing those notes | Cadence ruling |
|---|---|---|---|
| 1 | A・F・C | F (constituent notes match exactly) | F（T） |
| 2 | B♭・D | B♭ or Gm (both S) | Either works |
| 3 | E・G・C | C | C（D） |
| 4 | A | F or Dm (both T) | The first three measures form T→S→D, so return to T here; either works |
| 5–8 | (same method) | B♭ → F → C → F | S→T→D→T, closing on I |
Result: F → B♭(or Gm) → C → F(or Dm) ／ B♭ → F → C → F; overall function chain T S D T S T D T.
Second major-key example (C Major, 8 measures, melody containing non-chord tones): C → F → Dm → G ／ C → Am → Dm → G → C Degrees I → IV → IIm → V ／ I → VIm → IIm → V → I; functions T → S (IV and IIm chained) → D ／ T (I and VIm chained) → S → D → T — the cadence completes twice. Rule of thumb: trying to fit the cadence framework as much as possible first is the shortcut to improvement.
Caveat: real songs are full of examples that do not obey the theory. Insisting "the cadence must hold absolutely" can itself produce unnatural progressions — stay flexible and remember that "everything has exceptions."
Step 4: Handling Non-Chord Tones (非和声音)
Concepts
- 和声音 (Chord Tone): a melody note that belongs to the current chord's constituent notes.
- 非和声音 (Non-Chord Tone): a melody note that does not belong to the current chord's constituent notes (e.g., a D over a C chord).
All chord tones → correct but overly plain; saturated with non-chord tones → jarring (チグハグ). Balancing the ratio is a matter of experience and taste. Non-chord tones are "accessories," not "obstacles" — their urge to return to a chord tone generates forward momentum, a "slightly naughty charm (ちょいワルな色気)."
Three Behavioral Traits
- They "resolve" (非和声音の解決): a non-chord tone is essentially an altered form of a chord tone; most resolve to the nearest chord tone, and they may also resolve toward a constituent note of the next chord.
- They cannot be left hanging: a non-chord tone that jumps into the next chord unresolved sounds wrong. Fix: insert a better-fitting chord that turns the note into a chord tone (e.g., an awkward A between C→G — insert F, giving C→F→G).
- They come in four types:
| Type | Japanese (reading) | Definition |
|---|---|---|
| Passing tone | 経過音（けいかおん） | Moves stepwise in order through the space between two chord tones of different pitch |
| Appoggiatura | 倚音（いおん） | A non-chord tone falling on a strong beat, usually resolving by step up or down |
| Suspension | 掛留音（けいりゅうおん） | A chord tone of the previous chord held over as-is (often tied, タイ), becoming a non-chord tone over the new chord before resolving |
| Neighbor tone (auxiliary tone) | 刺繡音（ししゅうおん） | "Stitches" around a chord tone: chord tone → neighbor → back to the original note |
Practical Implications
- For the same melody, which note you interpret as the chord tone changes the harmonization (the same melody can take Dm→G or C→Dm) — adjudicate via cadence and surrounding context.
- Self-check after harmonizing: circle every non-chord tone and confirm each belongs to one of the four types and has a resolution destination.
- Reverse application: when writing accompaniment, deliberately embedding "non-chord tone → resolution" motion yields a forward drive that plain arpeggios cannot provide.
Minor-Key Harmonization (Based on the Harmonic Minor Scale)
The rules are (almost) identical to major — arrange diatonic chords by cadence. "Almost," because minor has three scales, and the diatonic chords differ subtly depending on which scale you use.
The Three Minor Scales
- 自然的短音階 (natural minor scale): whole–half–whole–whole–half–whole–whole; the minor key's signature is determined by this scale.
- harmonic minor scale: raises the 7th degree a semitone, creating the leading tone — entering the tonic from a semitone below; the leading tone is written with an accidental. Most important for harmonization; must be memorized.
- melodic minor scale: ascending, the 6th degree is also raised (eliminating the augmented 2nd, easier to sing); the descending form = natural minor.
Diatonic Chords of the Harmonic Minor Scale (C Minor as example)
| degree | Im | IIm(♭5) | ♭IIIaug | IVm | V | ♭VI | VIIm(♭5) |
|---|---|---|---|---|---|---|---|
| C minor | Cm | Dm(♭5) | E♭aug | Fm | G | A♭ | Bm(♭5) |
| function | T | S | ×almost never used | S | D | T※ | D |
Diatonic chords of all three scales compared (C Minor, for reference):
| scale | chords on each degree | function |
|---|---|---|
| harmonic minor scale | Cm・Dm(♭5)・E♭aug・Fm・G・A♭・Bm(♭5) | T・S・×・S・D・T・D |
| natural minor scale | Cm・Dm(♭5)・E♭・Fm・Gm・A♭・B♭ | T・S・T・S・D・T・S |
| melodic minor scale (ascending) | Cm・Dm・E♭aug・Fm・G・Am(♭5)・Bm(♭5) | T・S・×・S・D・T・D |
- Minor-key degrees are labeled relative to the relative major (A♭ in C Minor is written ♭VI).
- ♭IIIaug has a peculiar sound and is almost never used in ordinary cadences; the natural minor's ♭III can be viewed as "the relative major's I."
- ♭VI is treated as T in classical theory, but jazz/pop often treats it as S (its notes are close to IVm); this method adopts the easier-to-grasp classical reading, T.
In practice, master these 5 first: Im, IIm(♭5), IVm, V, ♭VI (in C Minor: Cm, Dm(♭5), Fm, G, A♭; functions T, S, S, D, T).
Basic minor example: A Minor harmonized as T→S→D→T gives Am → Bm(♭5) → E → Am (Im → IIm(♭5) → V → Im).
Key Technique: Inserting the Relative Major's V→I
Inserting the relative major's (平行長調) V→I into a minor progression creates a momentary brightness like "light breaking through a gap in the clouds" — extremely common.
C Minor 8-measure demonstration: Cm → Fm → B♭ → E♭ → A♭ → Dm(♭5) → G → Cm Degrees: Im(T) → IVm(S) → [E♭ Major's V(D) → I(T)] → ♭VI(T) → IIm(♭5)(S) → V(D) → Im(T)
The key to returning to the home key is using a common chord as the "hinge" (蝶番, ちょうつがい): A♭ is IV from E♭ Major's viewpoint and ♭VI from C Minor's, sliding the music smoothly back into the minor key.
Minor-Key Worked Example (A Minor, 3/4 Time, 8 Measures)
Exactly the same procedure as major: first list Am(Im,T), Bm(♭5)(IIm(♭5),S), Dm(IVm,S), E(V,D), F(♭VI,T), then match melody notes measure by measure and adjudicate by cadence. Sample solution:
Am → Dm → G → C ／ F → Bm(♭5) → E → Am
- First half: Im(T) → IVm(S) → [C Major's V(D) → I(T)] — the relative major mixed in mid-course;
- Second half: ♭VI(T) → IIm(♭5)(S) → V(D) → Im(T); the common chord F (C Major's IV / A Minor's ♭VI) acts as the hinge (蝶番);
- This progression is identical to the classic Autumn Leaves (枯葉); harmonizing measure 5 with Dm (IVm, S) is also fine — Dm is likewise a common chord of both keys.
Step 5: The Three Staple Progressions and Substitution
Substitution Rules (Two, for Beginners)
- Within a progression, I (T) may be replaced by IIIm (IIIm is I's substitute);
- In the S segment, IIm may be replaced by IV (and vice versa; same function, interchangeable).
Staple #1: 循環コード (Cyclic Progression)
I → VIm → IIm → V (C Major: C → Am → Dm → G), functions T→T→S→D. "Cyclic" means it can repeat indefinitely — the staple of staples (Stand by Me, etc.). Chained variant example: C→Am→Dm→G ／ Em→Am→F→G (I→VIm→IIm→V ／ IIIm→VIm→IV→V).
Staple #2: 逆循環コード (Reverse Cyclic Progression)
IIm → V → I → VIm (C Major: Dm → G → C → Am), functions S→D→T→T — i.e., the cyclic progression started from its S segment. Used mainly in major keys, arguably even more often than the cyclic form (ヘビーローテーション (Heavy Rotation), 君の瞳に恋してる (Can't Take My Eyes Off You), etc.). Most common development: repeat twice, ending on I the second time; or on the repeat, turn the final VIm into a VI major triad: Dm→G→Em→Am ／ Dm→G→C→A (IIm→V→IIIm→VIm ／ IIm→V→I→VI).
Staple #3: パッヘルベルのカノン型 (Pachelbel's Canon Type)
I → V → VIm → IIIm → IV → I → IIm → V (C Major: C → G → Am → Em → F → C → Dm → G). Especially common in J-POP (ハナミズキ (Hanamizuki), チェリー (Cherry), etc.). Its charm: from the constituent notes of the chords you can extract a stepwise descending melodic line that turns upward at the final chord — an emotional effect of "a sliver of hope suddenly emerging," extremely useful for both songwriting and accompaniment.
Transposition: move it by degree to any key (e.g., F Major: F C Dm Am B♭ F Gm C).
Step 6: Upgrading to 7ths
Core Conclusion: 7th Chords Have Exactly the Same Function as Their Triads
Major-key diatonic 7th chords (ダイアトニック7thコード, C Major):
| C△7 | Dm7 | Em7 | F△7 | G7 | Am7 | Bm7(♭5) |
|---|---|---|---|---|---|---|
| I△7(T) | IIm7(S) | IIIm7(※) | IV△7(S) | V7(D) | VIm7(T) | VIIm7(♭5)(D) |
So direct substitution is fine: C→F→G→Am (I→IV→V→VIm) ⇒ C△7→F△7→G7→Am7, no problem at all. Five to remember is enough: I△7, IIm7, IV△7, V7, VIm7.
V7 Is the Protagonist That Pulls the Music Forward
The most frequently used diatonic 7th is V7 (属七の和音, the dominant 7th chord): structurally the union of the triads V and VIIm(♭5) (G + Bm(♭5) = G7). Its Dominant pull is exceptionally strong — use it actively.
7ths Widen Your Harmonization Options
A melody note may be interpreted as the chord's 7th to justify a 7th chord (e.g., melody note B over C → harmonize with C△7). Many "nothing seems to fit" melodies suddenly open up. Even when the melody contains no 7th, you may use a 7th purely for the stylish sound.
Minor-Key 7ths (Harmonic Minor Scale, C Minor)
| Cm△7 | Dm7(♭5) | E♭△7(♯5) | Fm7 | G7 | A♭△7 | Bdim7 |
|---|---|---|---|---|---|---|
| Im△7(T) | IIm7(♭5)(S) | ×almost never used | IVm7(S) | V7(D) | ♭VI△7(T) | VIIdim7(D) |
The other two scales' 7th versions (for reference, C Minor):
- Natural minor: Cm7(Im7,T)・Dm7(♭5)・E♭△7(♭III△7,T)・Fm7・Gm7(Vm7,D)・A♭△7・B♭7(♭VII7,S)
- Melodic minor (ascending): Cm△7・Dm7(IIm7,S)・E♭△7(♯5)(×)・Fm7・G7・Am7(♭5)・Bdim7
Practical points for minor:
- Im△7 has a fairly jarring sound; the natural minor's Im7 is usually substituted for it;
- → Five to remember in minor: Im7, IIm7(♭5), IVm7, V7, ♭VI△7;
- The relative major's V→I can likewise be 7th-ized (V7→I△7, or 7th-ize only one of the two).
C Minor 8-measure comprehensive demonstration: Cm7 → Fm7 → B♭7 → E♭△7 → A♭△7 → Dm7(♭5) → G7 → Cm7 (Im7 → IVm7 → [relative major E♭'s V7→I△7] → ♭VI△7 → IIm7(♭5) → V7 → Im7)
Practical example of minor reverse-cycle + 7th-ized relative major (D Minor, 8 measures): Dm7 → Gm7 → C7 → F△7 ／ B♭△7 → Em7(♭5) → A7 → Dm The first half is [relative major F Major's V7→I△7] (C7→F△7); then the common chord B♭△7 serves as the hinge (蝶番) back to D minor (IIm7(♭5)→V7→Im).
Dosage Warning
7ths are rich and complex in sound — you need not use them everywhere: restricting yourself to V7 alone, or adding only IIm7, gives a calmer sound less likely to clash with the melody. Do not overdo it — "observe the dosage and directions; use correctly."
Classic-Song Proof: Less Is More
草競馬 (Camptown Races) (S. Foster, F Major) uses only 3 chords in the entire song: F(I), C7(V7), B♭(IV):
- Section [A]: F ↔ C7 — a plain alternation of T and D — the music just keeps pressing forward;
- Section [B]: the S-function B♭ makes its first appearance — a chord never heard before transforms the color, producing a flowing "the view suddenly opens up" sensation;
- Section [C] returns to C7→F to close.
Lesson: just 3 chords plus a simple melody can build a three-dimensional world; the "late arrival" of the S chord is a classic device for creating sectional color change. When harmonizing your own melody, you need not chase richness in every measure — first decide "which function makes its entrance in which section."
Quick FAQ
Q: The melody notes in a measure don't fully belong to any common chord? Treat the misfit notes as non-chord tones (confirm they belong to one of the four types and have a resolution destination) and choose the chord from the remaining notes; or interpret the note as a 7th and use a 7th chord; failing that, consider two chords in the measure, assigning the note to the second chord that fits it.
Q: Two candidate chords both make sense — which to pick? Function first — pick the chord whose function the cadence demands; among same-function parallel candidates (e.g., B♭ vs Gm, F vs Dm), choose by personal taste and color. There is no single correct answer.
Q: The melody sounds sad — can I conclude it's minor? No. Reason from accidentals plus the leading-tone test (Step 1); if genuinely ambiguous, decide by context and the piece's overall mood, and verify by actually playing and singing.
Q: Must each measure have exactly one chord? Beginner default is one per measure; when melody notes are dense or the function needs to switch, two chords per measure (usually split on the strong beat) is very common.
Q: Want a flash of brightness in a minor progression? Insert the relative major's V→I (or V7→I△7), then slide back to the home key via a common chord (the hinge, 蝶番).
Q: The result sounds too bland? Try in order: same-function substitution (IIIm for I, IV for IIm) → apply a staple progression → localized 7th-izing (V7 first) → have an S-function chord make a "late arrival" in a new section for a color change.
Quick Checklist
Self-check after harmonizing a melody:
- Key identification is grounded (accidental order + leading-tone test), and the relative key's alternative reading was considered
- All chords used are within the key's common 5 (major: I/IIm/IV/V/VIm; minor: Im/IIm(♭5)/IVm/V/♭VI), with justified exceptions
- The function chain reduces to the three cadence types (including same-function chaining), ending on I (or a deliberately open ending)
- Every melody note in each measure is either a chord tone or one of the four non-chord tone types with a resolution
- Minor keys harmonized from the harmonic minor scale; for momentary brightness, consider the relative major's V→I plus a common-chord "hinge" (蝶番) return
- 7ths used only where needed, V7 first
Terminology Quick Reference (Japanese → English)
| Japanese | English | Japanese | English |
|---|---|---|---|
| コードづけ | Harmonizing a melody | ダイアトニックコード | Diatonic chords |
| ケーデンス／カデンツ | Cadence | トニック（T） | Tonic function |
| ドミナント（D） | Dominant function | サブドミナント（S） | Subdominant function |
| 導音 | Leading tone | 平行調 | Relative major/minor keys |
| 和声的短音階 | Harmonic minor scale | アーメン終止 | Amen (plagal) cadence（IV→I） |
| 和声音／非和声音 | Chord tone / Non-chord tone | 経過音 | Passing tone |
| 倚音 | Appoggiatura | 掛留音 | Suspension |
| 刺繍音 | Neighbor tone (auxiliary tone) | 蝶番 | Hinge (common-chord pivot) |
| 循環コード | Cyclic progression | 逆循環コード | Reverse cyclic progression |
| パッヘルベルのカノン型 | Pachelbel's Canon type | 属七の和音 | Dominant 7th chord（V7） |
| 転回形 | Inversion | 定番コード進行 | Staple chord progression |