Bb Diminished chord (Bbdim) on the guitar fretboard

The Bb Diminished chord (Bbdim) is made of Bb (the root), Db (minor third) and Fb (diminished fifth). The fretboard shows every one of them across the neck in standard tuning (E A D G B E), and plays them back so you can hear the chord.

The diminished triad stacks two minor thirds, giving a root, a minor third and a flat five. It is a compact, symmetrical shape that tends to repeat at regular distances on the neck. Add a seventh and it becomes the diminished seventh or the half diminished chord.