Guide Tones I

The Guide Tones I voicing of A7b5 stacks C# and G from the bottom up: the major 3rd and minor 7th of the chord. It leaves out the root, A, for the left hand or the bass player to take.

It's one of the Guide Tones voicings: just the 3rd and 7th, the notes that define each chord, played over the root. The other for A7b5 is Guide Tones II.