A Mode 6 Scale
A Mode 6 contains 8 notes: A, B, C♯, D, D♯, F, G, G♯. It has 3 sharps: C♯, D♯, G♯. The step pattern is W–W–H–H–W–W–H–H.
Messiaen Mode 6 is an 8-note scale with 6 possible transpositions. Two whole-tone tetrachords connected by half steps give it a floating quality with strategic anchor points.
The formula is 1, 2, 3, 4, b5, b6, b7, 7. Each group of 4 notes moves in whole tones, and the groups connect by half step. The result sounds "whole-tone-ish" in small fragments but breaks the whole-tone symmetry at specific points. Messiaen valued this ability to create whole-tone floatiness with structural interruptions.
Excellent for exploiting diminished and augmented intervals to break away from diatonic cliches. Practice the two whole-tone tetrachords separately, then work on the half-step connections between them. The symmetry makes transposition straightforward.