Barry Harris taught that one diminished 7th chord creates a whole family of four dominant 7th chords! Because diminished chords are symmetrical, every note can resolve down a half-step to become a new dominant root. One chord can unlock multiple jazz substitutions, smooth voice-leading, and endless bebop movement. This is one of the secrets behind the flowing harmonic sound of bebop piano. For example, a B diminished chord can generate G7, Bb7, Db7, and E7, forming one dominant family. Chart included.