Fdim

Fdim is F, Ab and Cb, a diminished triad. The shape this page opens on is written xx34x4, lowest string first.

Also written F°, Fo or F diminished. The same chord either way; which spelling you meet depends on who wrote the chart.

There are 4 common shapes for Fdim on the guitar, and 48 derived voicings in the triad family.

In which keys. Every note of Fdim belongs to Eb minor (the ii°) and F# major (the vii°).

The common shapes, written lowest string first: xx34x4, x86x67, x-8-9-10-9-x, 13-11-x-13-12-x.

Triad. Three notes across one string set. Fdim has xx310x, xxx101, x231xx, xx3101, 1231xx, x2310x, 423xxx, 4234xx.

Tensions. A shell of Fdim, root, third and seventh, leaves a string free, and the tones that belong over it are the 11 (Bb) and the b13 (Db).

The common shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.