How to play Bm7 (B m7) on Bass

Bm7 is the B m7 chord. It is built from 4 notes — B, D, F# and A — which sit at the root, minor third, perfect fifth and minor seventh above the root B. Written as a formula that is 1P – 3m – 5P – 7m. Those intervals, not the note names, are what give the chord its character: move all of them to a different root and you still hear a m7 chord.

Bm7 on bass is a movable shape with no open strings, fretted between fret 7 and fret 9, the shape spans 3 frets, 2 strings are muted and should not sound — damp them with the underside of a fretting finger. Since the shape uses no open strings it is fully movable: slide it one fret higher and you have the same chord a semitone up, which is the cheapest way to learn eleven more chords from one hand position.

The interval that defines this chord is the minor third between B and D. Lowering the third by one semitone is the entire difference between B major and B minor, and it is the reason the chord reads as darker or sadder to most listeners. The added minor seventh stops the chord from sounding like a resting place — it leans forward and wants to resolve, which is exactly why it turns up at the end of a phrase rather than the start.

Bm7 belongs to 3 major keys, including G major, where it is the iii chord, D major, where it is the vi chord and A major, where it is the ii chord. That is the practical reason to learn it: a chord that is diatonic to several keys turns up constantly, and knowing which degree it occupies tells you what tends to come next. A iii chord in G major most often moves toward the tonic, so practising Bm7 in the context of G will teach you more than practising it in isolation.