C Half Whole Diminished — Vihuela

C Half Whole Diminished is 8 notes per octave (symmetric family), drawn here as position boxes on the Vihuela's ADGBE grid with the root flagged in each — learn one box deeply, then let the overlaps carry you into the next.

Tense, symmetrical, and slightly sinister — alternating half and whole steps pack in the b9, #9, #11, and 13, so it sounds like a dominant chord stretched to breaking point. Edgy, jazzy, and restless.

Heard in: Jazz lines over 13b9 dominant chords, fusion, film-noir and horror scoring — the sound of a V chord that refuses to settle.

The grid under these maps is the standard one, so the boxes are the boxes guitarists already know — the ADGBE grid.

Play each box top to bottom until the roots feel like home base, then practice crossing between boxes mid-phrase — neck freedom is exactly that crossing, nothing more.