D major only uses four strings, which makes it the easiest open shape to hear a single finger move clearly against the others. This post works through the same set of variations as the A-shape post, applied to D.

Base shape: D major

Suspended: sus2 and sus4

Both suspensions here move only the top string, the string carrying the third in the base shape -- the clearest possible illustration of what "suspended" means.

Minor and minor seventh

Dominant seventh and major seventh

D7 is the shape most players learn first for a dominant chord -- useful as the V in a blues in G (see the 12-bar blues post).

Sixth and add9

D6 lifts the third's neighbour to add the sixth. Dadd9's most common open voicing shares fingering with Dsus2 -- the difference on paper is whether the third from a lower voicing is implied by the bass notes ringing under it in a full mix.

Summary table

Chord	Frets (low to high)	Change from D major
D	xx0232	base shape
Dsus2	xx0230	remove 3rd
Dsus4	xx0233	3rd -> 4th
Dm	xx0231	major 3rd -> minor 3rd
Dm7	xx0211	Dm, drop a finger
D7	xx0212	add b7
Dmaj7	xx0222	add maj7
D6	xx0202	add 6th
Dadd9	xx0230	add 9th

Next in the series: the E-shape open chord variations.