Harmonic Superimposition

Harmonic superimposition means playing a complete, self-consistent harmonic idea — a triad, a ii–V, a whole reharmonized cycle — on top of chords that aren’t actually there. The rhythm section keeps playing Dm7–G7–Cmaj7, but your line implies something else entirely, and for a beat or two you’re living in two keys at once. It’s how players escape the gravity of the changes without just throwing in random wrong notes: the escape has its own internal logic, so the ear can follow it even while it clashes.

Borrowing a Structure, Not Breaking One

The key word is structure. A superimposed idea works because it’s a complete, recognizable shape — a triad, an arpeggio, a full ii–V–I — not scattered dissonance. Play any three random “wrong” notes over a Cmaj7 and it just sounds like a mistake; play a fully formed B major triad over it and the ear hears another chord, something with its own gravity, even though it’s a minor second away from home. That distinction — organized harmonic distance versus noise — is what separates superimposition from simply Playing Outside, which is the broader umbrella term for any kind of harmonic reach beyond the written changes.

Triads and ii–V’s on Top of the Changes

The simplest superimpositions are triads a set interval from the underlying chord, chosen because their notes land on rich upper extensions:

Over G7, an A major triad (A–C♯–E) outlines the 9th, ♯11, and 13th — a textbook upper structure triad.
Over Dm7–G7–Cmaj7, an ascending B major arpeggio (B–D♯–F♯) cuts across the G7 before resolving into Cmaj7.
Over a static D minor vamp, a soloist can imply E♭m7–A♭7 — a ii–V a half step up — laying an entirely different tonal center over the same pedal point, a favorite move in Modal Improvisation.

The A major triad spells out G7’s upper structure directly:

This overlaps with Triad Pairs (two triads superimposed against each other for color) and with Side-Slipping, though side-slipping is really a half-step nudge for tension-and-resolution rather than a fully realized second harmony — worth keeping the two separate even though they get confused often.

Coltrane Changes: Superimposition as a System

John Coltrane turned superimposition into a compositional method rather than a one-off gesture. Over a plain Dm7–G7–Cmaj7, Coltrane Changes insert two extra dominant approach chords to cycle through three key centers a major third apart:

Dm7 | E♭7 | A♭maj7 | B7 | Emaj7 | G7 | Cmaj7

Compressed to two chords per bar, the three key centers arpeggiate past in a single chorus:

The three superimposed key centers — A♭, E, and C — sit a major third apart, an equilateral triangle stacked on top of a plain ii–V–I in C

Each dominant resolves normally — this is still Dominant Resolution, just compressed and multiplied — but the overall effect is three tonal centers stacked into one turnaround. It’s the harmonic backbone of Giant Steps and shows up constantly in Coltrane’s Sheets of Sound lines, where rapid-fire arpeggios make the superimposed structure audible in real time. The major-third key cycle also echoes the non-functional, pattern-driven root motion behind Constant Structure progressions — roots chosen for symmetry and color rather than for their pull toward a single tonic.

McCoy Tyner’s Quartal Layer

Superimposition isn’t only melodic — McCoy Tyner built it into his comping. Over a static modal vamp he’d voice parallel stacks of fourths (C–F–B♭ moving to D♭–G♭–C♭, for instance) that shift independently of both the bass note and the soloist’s line. This is Quartal Harmony used as a harmonic superimposition device: the voicings imply motion and color the vamp never states outright, functioning almost like an on-the-fly Reharmonization happening underneath the soloist rather than through Chord Substitution of the written changes.

♫ Listen

John Coltrane — “Body and Soul” (Coltrane’s Sound, rec. 1960): the bridge is Coltrane changes layered over a standard ballad progression, with Tyner’s thick quartal voicings reharmonizing underneath in real time.
John Coltrane — “My Favorite Things” (My Favorite Things, 1961): Tyner’s fourths-based vamp under the soprano melody is a clear case of harmonic superimposition living entirely in the comping, independent of the tune’s static E chord.