Open D tuning (D-A-D-F#-A-D) is an alternate guitar tuning where all six open strings form a D major chord. Strumming all open strings without fretting produces a full, resonant D major sound. It is one of the most widely used open tunings and is a cornerstone of blues, folk, and slide guitar playing.

To tune to Open D from standard EADGBE: lower the 6th string (E) down one whole step to D, keep the 5th string (A) the same, lower the 4th string (D) stays the same, lower the 3rd string (G) one whole step to F#, keep the 2nd string (B) as is, and lower the 1st string (high E) one whole step to D. Use the tuner above to verify each string.

Open D tuning has been used by many iconic musicians. Joni Mitchell used it extensively on songs like 'Big Yellow Taxi.' Bob Dylan used it on classic recordings. Jack White of The White Stripes built a large part of his style around Open D and slide guitar. Blues legends Son House and Robert Johnson played in Open D. More recently, Jason Isbell and other Americana artists have used it for its resonant, open sound.

Notable songs in Open D tuning include 'Big Yellow Taxi' by Joni Mitchell, 'Death Letter' by Son House (a blues slide classic), 'Little Martha' by the Allman Brothers Band, 'Bron-Y-Aur Stomp' by Led Zeppelin, and many of Jack White's songs and riffs. The tuning is especially prevalent in Americana, folk, and Delta blues repertoire.

Open D is approachable for beginners in some ways and more challenging in others. Because the open strings form a chord, simple strumming and single-note slide playing are immediately rewarding. However, standard chord shapes no longer apply — you need to learn new fingering patterns. Open D is most accessible when used with a slide (bottleneck), where you can play melodies and chords by simply laying the slide across any fret.