For example, the minor seventh chord built on A, commonly written as A−7, has pitches A–C–E–G:
Minor/minor seventh chord
A seventh chord with a minor third, perfect fifth, and minor seventh is commonly called a minor seventh chord, but also sometimes a minor/minor seventh chord to distinguish it from the minor/major seventh chord discussed below. It can be represented as either as m7 or −7, or in integer notation, {0,3,7,10}.
The major sixth chord (major triad with an added major sixth) is an inversion of this chord.
Minor/major seventh chord
When the seventh note is a major seventh above the root, it is called a minor/major seventh chord. For example, the minor/major seventh chord built on C, commonly written as CmM7, has pitches C–E♭–G–B:
Its harmonic function is similar to that of a "normal" minor seventh, as is the minor seven flat five or half-diminished chord – but in each case, the altered tone (seventh or fifth, respectively) creates a different feeling which is exploited in modulations and to use leading-tones.
The just minor seventh chord is tuned in the ratios 10:12:15:18.[9]Playⓘ This may be found on iii, vi, and vii.[10] Another tuning may be in the ratios 48:40:32:27.[11]Playⓘ
Minor seventh chords for guitar
In standard tuning, the left is the low E string, the number is the fret, and x means mute the string.