Chord Progressions

If a single chord is a data structure, a chord progression is an algorithm: an ordered sequence of chords that moves a listener somewhere over time. This chapter is about that ordering — why some sequences feel like "going home" and others feel like an endless forward loop — and how MidiSketch picks from 22 ready-made progressions.

Chord progression

A chord progression is an ordered sequence of chords played one after another, usually looping over a section of a song. Order matters: the same set of chords arranged differently produces a different emotional path. Progressions are written in degree (Roman numeral) notation so they transpose to any key — I-V-vi-IV means the same relationship whether you are in C, G, or any other key.

Harmonic function: home, away, and the pull back

Before looking at specific progressions, it helps to know that each chord in a key plays one of three structural roles. These roles are why progressions feel directional rather than random.

Tonic / subdominant / dominant function

Every chord in a key has a function — a structural job. The tonic (built on degree 1, I) is home: stable, resolved, at rest. The dominant (built on degree 5, V) is maximum tension; it strongly pulls back toward the tonic. The subdominant (built on degree 4, IV) is the in-between "away" zone that sets up the dominant. Most progressions are just a walk between these three poles.

Tension and resolution

Tension is the feeling that the music is unstable and wants to move; resolution is the release when it lands on a stable chord. Composers create tension (usually with a dominant chord) precisely so they can resolve it. The interplay of the two over time is the single most important engine of Western harmony — a progression is essentially a tension curve.

Tension curveA full phrase: I-IV-V7-I

The classic full sentence of tonal harmony: start at home (I), move away (IV), peak the tension (V7), and resolve (I). Almost any progression you analyze decomposes into some walk along this stable-tense-resolved cycle.

tensionresolutionStable, lifting, tense, resolved: progressions are tension curves over time.

The four-chord sentence above is the cleanest illustration of the cycle: it leaves home, builds, peaks, and returns. Almost every progression you analyze decomposes into some walk along this same stable-tense-resolved path.

Cadences: how a phrase signals "we arrived"

A progression needs punctuation. The musical equivalent of a period at the end of a sentence is the cadence.

Cadence

A cadence is a short chord motion that ends a phrase, most often the dominant resolving to the tonic (V→I). It is the harmonic punctuation mark that tells the ear a phrase has finished. The strength of the "arrival" depends on the chords involved — a V→I cadence is the strongest and most conclusive.

CadenceV to I: the strongest resolution

G7 contains the unstable pair B-F (a tritone), which "wants" to collapse onto C-E. That pull-and-release, called a cadence, is how phrases signal "we have arrived". Listen for the relief on the final C chord.

cadenceV-IThe dominant (V) pulls toward home (I) — release the tension and the phrase ends.

Notice that the resolution is driven by a single unstable interval inside the dominant chord that "wants" to collapse onto the tonic. That mechanism — and how to exploit it — is the subject of the next chapter on harmonic color.

The Royal Road: J-pop's signature loop

Not every progression resolves cleanly. Some are designed to keep floating forward, never quite settling, which is exactly what makes a chorus feel like it could loop forever.

Royal Road progression (王道進行)

The Royal Road progression (王道進行, ōdō shinkō) is IV-V-iii-vi, an extremely common loop in Japanese pop. Its defining trait is that it never lands on the tonic — it lifts on the subdominant, drives on the dominant, then sidesteps into minor chords instead of resolving home. The result is a bittersweet, perpetually forward-leaning feel.

Royal RoadThe "Royal Road" progression: IV-V-iii-vi

In C major this reads F → G → Em → Am. It never sits on the home chord, so it keeps floating forward — the reason countless J-pop choruses use it. MidiSketch ships it as one of the 22 preset progressions.

chordProgressionIdIV-V-iii-viThe signature J-pop loop: lift (IV), drive (V), shade (iii), land (vi).

Because it sidesteps the tonic, the Royal Road creates motion without closure — the harmonic equivalent of a loop that never returns to its initial state. MidiSketch ships this as one of its preset progressions, selectable by id.

The four-chord loop and the canon progression

The most recycled loop in Western pop is a close cousin: four diatonic chords that complete a full emotional arc and then repeat.

Four-chord loop / canon progression

A four-chord loop is any short four-chord cycle repeated throughout a song; the canon progression is the famous descending version (I-V-vi-IV and its relatives) named after Pachelbel's Canon. These loops are popular because four chords are enough to trace a complete home → away → sad → hopeful arc while staying simple enough to memorize instantly.

Four-chord popThe four-chord loop: I-V-vi-IV

C → G → Am → F. Hundreds of hit songs share this exact loop. It starts at home (I), wanders (V), darkens (vi), and brightens back (IV) — a complete emotional arc in four chords.

chordProgressionIdI-V-vi-IVHome, away, sad, hopeful — the most recycled loop in Western pop.

The I-V-vi-IV loop starts at home and returns, unlike the Royal Road, which is why it feels resolved yet still danceable on repeat. Both are just different orderings of mostly the same diatonic chords — the ordering is the whole design.

Borrowed chords: stepping briefly outside the key

Every progression so far stays inside the seven diatonic chords. A progression can also pull a single chord in from outside the key for a splash of color — without changing where the song calls home.

Borrowed chord (♭VII)

A borrowed chord is a chord taken from the parallel key (here, the parallel minor) and dropped into an otherwise diatonic progression. The most common one in pop and rock is ♭VII — in C major, a B♭ major chord. Its root sits a whole step below the tonic instead of the diatonic vii°, giving a bright, anthemic lift that falls back to I. It is the signature sound of the I-♭VII-IV-I rock cadence.

Borrowed ♭VIIThe ♭VII rock cadence: I - ♭VII - IV - I

C → B♭ → F → C trades the leading-tone pull of a diatonic cadence for a bright, plagal brightness. The ♭VII chord (B♭ major) is borrowed from the parallel minor; its root sits a whole step below the tonic instead of the diatonic vii°. This is the signature sound of countless rock and anime choruses. MidiSketch ships two such Rock presets, selectable via chordProgressionId like any other progression.

chordProgressionIdI-bVII-IV-IB♭ is borrowed from outside C major — a whole step below the tonic — for an anthemic, mixolydian lift.

I-♭VII-IV-I (C - B♭ - F - C) trades the leading-tone pull of a diatonic cadence for a plagal, mixolydian brightness — the move behind countless rock and anime choruses. MidiSketch ships two such progressions (the Rock presets), selectable like any other via chordProgressionId; ♭VII is the only borrowed chord in the preset set, and the engine voices and analyzes it correctly even though it sits outside the key.

Vamps: a progression can be tiny

Loop length is itself a stylistic choice. A progression does not need three or four chords; two are often enough to establish a mood.

Vamp

A vamp is a very short repeated progression — often just one or two chords — used as a hypnotic, atmospheric backdrop. Modern pop, lo-fi, and electronic styles lean on vamps because the relentless repetition is the point: it frees the melody and rhythm to carry the song. Short loops trade harmonic variety for groove and immediacy.

Two-chord vampProgressions can be tiny: Am-F loop

Not every song needs a long chord journey. A two-chord vamp (here Am ↔ F) creates a hypnotic, lo-fi atmosphere. Loop length is a stylistic choice: blueprints like BehavioralLoop intentionally exploit very short, repetitive loops.

loopvampTwo alternating chords already make a mood — modern pop loves short loops.

A two-chord vamp like Am↔F already carries a complete mood. MidiSketch treats loop length as a deliberate parameter: blueprints such as BehavioralLoop intentionally exploit very short, repetitive loops to maximize stickiness — a design we revisit in Chapter 7.

MidiSketch mapping

Concept	MidiSketch control	Notes
Choosing a progression	chordProgressionId (0-21)	22 preset progressions; getChords() lists them all
Borrowed chord (♭VII)	chordProgressionId (Rock presets)	I-♭VII-IV-I / I-IV-♭VII-I; the only borrowed chord in the preset set
How progressions are written	degree (Roman numeral) notation	e.g. IV-V-iii-vi, key-independent so it transposes to any key
Loop length as a style choice	short vamps vs. long cycles	BehavioralLoop blueprint exploits very short loops (forward reference, Chapter 7)

Engine reference: Harmony

Next chapter: Harmony & Color