3-string chords
Why learn 3-string chords? One reason is to enrich your playing and expanding your repertoire. One of the primary ways to use these chords is together up and down the fretboard. Since you can use the same moveable shapes, these chords will not claim to much space in your memory room.
These chords are not mainly to use together with open chords or bar chords, since it would in many cases not sound especially well. The best practice is, as mentioned above, to use them together and with the possibilities to combine with melody lines from the major scales (or other scales of course) on the same strings.
These chords could also be called voicings, since the order of notes is often alternative to the standard chords with the root as the bass note.
3-string major shapes
C
The diagram above shows a C Major chord played with three strings with the bass note on the fifth fret. The chord is moveable so you could move it along the fretboard and create other 3-strings major chords. Among the 3-string chords presented here, these actually doesn't sound especially great. A possible voicing of C major on the three highest strings is XXX988.
Short notation for all major chords with this shape
AX X X 2 2 0
A# / Bb X X X 3 3 1
B X X X 4 4 2
C X X X 5 5 3
C# / Db X X X 6 6 3
D X X X 7 7 4
D# / Eb X X X 8 8 5
E X X X 9 9 6
F X X X 10 10 7
F# / Gb X X X 11 11 8
G X X X 12 12 9
G# / Ab X X X 13 13 10
3-string minor shapes
Cm
The diagram above shows a C Minor chord played with three strings with the bass note on the fifth fret. This is the first of two minor chords with moveable shapes on the three highest strings.
Short notation for all minor chords with this shape
Am X X X 2 1 0
A#m / Bbm X X X 3 2 1
Bm X X X 4 3 2
Cm X X X 5 4 3
C#m / Dbm X X X 6 5 4
Dm X X X 7 6 5
D#m / Ebm X X X 8 7 6
Em X X X 9 8 7
Fm X X X 10 9 8
F#m / Gbm X X X 11 10 9
Gm X X X 12 11 10
G#m / Abm X X X 13 12 11
Em
The diagram above shows an E Minor chord played with three strings with the bass note at the fifth fret (notice that the root is not on the lowest string).
3-string dominant 7th shapes
B7
The diagram above shows a B major seventh chord played with three strings with the bass note on the fourth fret, third string. Notice the close likeness to the three string dominant 7th shape.
Short notation for all 7th chords with this shape
G7 X X X 0 0 1
G#7 / Ab7 X X X 1 1 2
A7 X X X 2 2 3
A#7 / Bb7 X X X 3 3 4
B7 X X X 4 4 5
C7 X X X 5 5 6
C#7 / Db7 X X X 6 6 7
D7 X X X 7 7 8
D#7 / Eb7 X X X 8 8 9
E7 X X X 9 9 10
F7 X X X 10 10 11
F#7 / Gb7 X X X 11 11 12
3-string major 7th shapes
Bmaj7
The diagram above show a B major seventh chord played with three strings with the bass note at the fourth fret, third string. Notice the close likeness to the three string dominant 7th shape.
Short notation for all maj7 chords with this shape
G7 X X X 0 0 2
G#7 / Ab7 X X X 1 1 3
A7 X X X 2 2 4
A#7 / Bb7 X X X 3 3 5
B7 X X X 4 4 6
C7 X X X 5 5 7
C#7 / Db7 X X X 6 6 8
D7 X X X 7 7 9
D#7 / Eb7 X X X 8 8 10
E7 X X X 9 9 11
F7 X X X 10 10 12
F#7 / Gb7 X X X 11 11 13