Since these chords share two or more notes, the melody usually still fits perfectly, but the "mood" of the stability changes. 2. Tritone Substitution
Any dominant chord (V7) can be preceded by its related minor seventh (ii7). G7 — C Expanded: Dm7 — G7 — C Reharmonization Techniques
You can create forward motion by "treating" any chord in a progression as a temporary tonic and preceding it with its own V7 chord. C — Am — Dm — G7 Reharmonized: C — E7 — Am — A7 — Dm — G7 Since these chords share two or more notes,
Swap a IV (F major) for a ii (D minor).
The "engine" of a G7 is the tritone between its 3rd (B) and 7th (F). A Db7 uses these same two notes (the 3rd is F, the 7th is Cb/B), creating a smooth, chromatic bass descent to the target chord. 3. Secondary Dominants G7 — C Expanded: Dm7 — G7 —
Apply this to a Tritone Sub. Instead of just Db7, use Abm7 — Db7 — C . 7. Pedal Points
The most important rule is that the new chord must not contain a note that "clashes" (usually a minor 9th interval) with the melody note being held.