Adim

Adim is A, C and Eb, a diminished triad. The shape this page opens on is written x0121x, lowest string first.

Note by note. A is the root, C is the minor third and Eb is the flat fifth.

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

There are 5 common shapes for Adim on the guitar, and 47 derived voicings in the triad family.

One note away. Change a single note of Adim and you have Am (with one note moved), Adim7 (with one note added), Am7b5 (with one note added), AmMaj7b5 (with one note added), Am/C (with one note moved) or Am/E (with one note moved).

In which keys. Every note of Adim belongs to G minor (the ii°) and Bb major (the vii°).

The common shapes, written lowest string first: x0121x, 53x54x, xx78x8, x-12-10-x-10-11, x-12-13-14-13-x.

Under the hand. 1 of the 5 shapes here sits in open position, and the first uses 1 open string with 2 left unplayed. None of them needs a barre. Together they cover the neck from the 1st fret to the 14th.

Triad. Three notes across one string set. Adim has x312xx, xx121x, x0121x, x3121x, xxx545, x675xx, 5675xx, 867xxx.

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

What kind of chord this is. Adim is a diminished chord — root, minor third, flat fifth. diminished and half-diminished chords on every root, and what they are for.

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