A Minor 7th
m7
0 - 3 - 7 - 10Minor + minor 7th
About A Minor 7th
A minor seventh is A minor with one finger removed. Lift the ring finger from the standard shape and the G string rings open, adding the seventh — a chord that costs less effort than the triad it comes from and sounds considerably more spacious.
The notes
A, C, E, G — all natural, like A minor itself. The G is the seventh, and it is the note that turns a plain minor triad into something that can sit still for bars at a time without growing heavy.
The chord shares three of its four notes with C major. That overlap is why Am7 and C often substitute for one another in arrangements, and why a bassline can move between them almost unnoticed.
On the fretboard
The open shape uses two fingers. A fuller version adds the little finger at the third fret of the high E, giving Am7 with the seventh doubled on top — brighter, and common in fingerstyle.
Barred at the fifth fret with the root on the low E string, the same chord becomes movable, and that shape is the one used when the song needs A minor seventh to be part of a line rather than a strum.
Where it shows up
As the ii of G major, the vi of C, and the tonic of a modal vamp in A. The ii role dominates in jazz: Am7–D7–G is the ii–V–I of the guitar’s favourite key.
In soul and bossa the chord is often the whole harmony of a section — one bar of Am7 repeated, with the melody supplying the movement. A plain A minor cannot do that job; the seventh gives it room.