Slack Key Tuning
Tune your ukulele to Slack Key — G3, C4, E4, G4
About Slack Key Tuning
Slack Key tuning (G3-C4-E4-G4) is inspired by the Hawaiian slack-key guitar tradition known as ki ho'alu. The 1st string is tuned down from A to G, creating an open C major chord when all strings are strummed. Combined with a low G on the 4th string, this tuning produces a rich, resonant sound rooted in Hawaiian musical tradition.
Hawaiian slack-key guitar dates back to the 1830s when Mexican and Spanish cowboys brought guitars to Hawaii. Hawaiian musicians developed their own open tunings by "slacking" the strings to lower pitches. Adapting this concept to ukulele creates a similarly lush, open sound that naturally lends itself to Hawaiian melodies and fingerpicking patterns.
The open C major chord means you can create full-sounding music with minimal fretting. Barre chords at any fret produce major chords, and simple two-finger shapes create beautiful seventh and suspended voicings. Slack Key tuning particularly rewards a fingerpicking approach where you let open strings ring while picking melody notes on the fretted strings.
String Notes
Recommended Strings
Slack Key tuning works best with a wound or fluorocarbon Low G string on the 4th string, paired with standard strings for the C, E, and G positions. Since the 1st string tunes down from A to G, standard strings handle this easily. The low G4-to-G3 on string 4 requires a dedicated Low G string — a re-entrant G4 string won't work.
How to Tune to Slack Key
- 1.Start from Low G tuning (G3-C4-E4-A4). If you're in standard re-entrant tuning, you'll need to swap the G string for a Low G string first.
- 2.The G (4th), C (3rd), and E (2nd) strings stay the same as Low G tuning: G3, C4, and E4.
- 3.Tune the 1st string down from A4 to G4. Lower the pitch until it matches the 4th string an octave higher, or fret the 2nd string at the 3rd fret to get G4 as a reference.
- 4.Strum all four strings open — you should hear a clear, ringing C major chord (the notes G-C-E-G spell out C major).
- 5.Verify the octave relationship: the 4th string (G3) should sound exactly one octave below the 1st string (G4).
Common Chords in Slack Key
C Major (open)
Strum all four strings with no fingers. The open tuning gives you a full, resonant C major chord instantly.
F Major (barre at 5th)
Barre all strings at the 5th fret for F major. Slide this shape to any fret for other major chords.
G Major (barre at 7th)
Barre at the 7th fret. Combined with the open C, this gives you the classic I-IV-V progression in the key of C.
Am7
Simply lift the barre and fret the 3rd string at the 2nd fret. The open G strings create a beautiful Am7 voicing.