Here is a quick guide to chords in the key of Bb (B flat) or A# (A sharp) minor.
| 1st | 2nd | 3rd | 4th | 5th | 6th | 7th |
| Minor | Dim | Major | Minor | Minor | Major | Major |
| i | iiº | III | iv | v | bVI | bVII |
| Bbm | Cº | Db | Ebm | Fm | Gb | Ab |
| A# | B# | C# | D# | E# | F# | G# |
The notes of a Bb minor (natural) scale are:
| 1st | 2nd | 3rd | 4th | 5th | 6th | 7th |
| Bb | C | Db | Eb | F | Gb | Ab |
written as A# minor (natural), this would be:
| 1st | 2nd | 3rd | 4th | 5th | 6th | 7th |
| A# | B# | C# | D# | E# | F# | G# |
Natural Minor Scale Formula
The scale notes above follow the 'natural minor' scale formula of 'steps':
WHOLE – HALF – WHOLE – WHOLE – HALF – WHOLE – WHOLE
Or 'tones':
TONE – SEMITONE – TONE – TONE – SEMITONE – TONE – TONE
Or even, on a guitar, frets:
Two frets – One Fret – Two Frets – Two Frets – One Fret – Two Frets – Two Frets
Which gives us the following interval relationships from the tonic (1st note):
- Union
- Major 2nd
- Minor 3rd
- Perfect 4th
- Perfect 5th
- Minor 6th
- Minor 7th
- Octave
All the chords in the key of Bb minor are made up of notes from the Bb minor (natural) scale.