Cdim

Cdim is C, Eb and Gb, a diminished triad. The shape this page opens on is written x31x12, lowest string first.

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

There are 5 common shapes for Cdim on the guitar, and 46 derived voicings in the triad family.

In which keys. Every note of Cdim belongs to C# major (the vii°) and Bb minor (the ii°).

The common shapes, written lowest string first: x31x12, x3454x, 86x87x, x-x-10-11-x-11, x-15-13-x-13-14.

Triad. Three notes across one string set. Cdim has 231xxx, x3454x, x645xx, xx454x, x6454x, xxx878, x-9-10-8-x-x, 8-9-10-8-x-x.

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

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