Open Cm tuning
The open Cm tuning is an alternative tuning for guitar. It only diviate with one half note compared to the open C major tuning.
To get the open C minor tuning on your guitar, you tune it like this: CGCGCEb. The strings that differ from the standard should be turned so the string tension is decreased and not the opposite. The exception is the second string which should be tuned up from B to C. This will increase the tension on that string, but only with a semi-step which normally don't result in string breakage.
More info
Including an octave perspective, the tuning is written C2-G2-C3-G3-C4-Eb4, meaning that the lowest string is a C note on the second octave, the second lowest string is a G note on the second octave and so on. Standard tuning reference: E2-A2-D3-G3-B3-E4.
Chords
Cm
Cm7
Cm9
Ebmaj7
Ab
Fm
Gm7
Bbmaj7
Comments
The Ebma7 chord version is an inversion and is more correctly written Ebmaj7/Bb, but is chosen here since its fingerings are straightforward.
The Fm chord version is also an inversion and is more correctly written Fm/Ab. It's chosen here since it offers a natural fingering.
The Gm7 is probably easiest to play with a finger baring the fourth highest strings on the second fret.
Additional open chords in this
tuning:
Cm6/9: 022000
Cmadd2: 002000
Csus4: XX0002
Ddim: XX2122
Dm7b5: XX2102
Eb5: XX3330
Eb6: 330000
Fm/C: XX0102
See below for pdf chord chart ("Essential Chords in Open Dm Tuning ebook") for many more voicings, progressions etc.
Movable shapes
Fm
Gm
Fm
Gm
Eb
Ab
Bb
Comments
These are the main diatonic major and minor chords in the key of Cm. The minor iv and v chords can as the diagram shows be played either with full or half one-finger barre fingerings.
Other possibilities for
one-finger chords in Open C minor
tuning:
Dbm: 111111 / XX1111
Ebm: 333333 / XX3333
Fm: 555555 / XX5555
Gm: 777777 / XX7777
Am: 999999 / XX9999
Chord progressions
Progressions in this specific tuning:
Ab (XX8889) - Gm7 (XX7777) - Eb (XX3334) - Cmsus4 (XX0002) - Cm (XX0000)
C Minor 7th tuning
Besides the C-G-C-G-C-Eb version presented here, there are the less known Open C Minor 7th tuning: C-G-C-G-Bb-Eb.
Some chords in Open Cm7
Tuning:
Cm7: 000000 / 003500
Cm9: 033040
Cm11: 033002
Ebmaj7/Bb: X32000
Ebmaj13/G: X02200
Gm6/D: XX02001
Bbmaj7/D: XX02202
See also open Dm tuning and open Gm tuning