F Locrian

The F Locrian mode — F Gb Ab Bb Cb Db Eb — shown across the guitar neck.

Swipe the neck sideways to see the higher frets.

F Locrian is the natural minor with the b2 and b5 — Gb and Cb. Those are the notes that give it its character.

The tool shows this from its parent key, F# major, with E# — the same pitch as F — marked as where Locrian begins, the same seven notes centered on F#.