A♯ (B♭) Diminished chord

The diminished triad stacks two minor 3rds (1–♭3–♭5). Tense and unstable, it is often built on the 7th degree of a major key and pulls strongly back to the tonic.

Root Chord tone✕ = don't playNumbers show the interval (1 = root, 3 = third, 5 = fifth…).
e
B
♭3
G
1
D
♭5
A
1
E
0
1
2
3
4
5