“So clearly it is fun to mess around and discover new chords in open d just using the chords we know, but what if we have a progression in mind, maybe you had played it on a different instrument or standard tuning but we want to apply it to this cool new sound of open d? Well this is how I recommend it:
Usually you want to start with the root (base) note and do some ‘music math’ to figure out where you want to go. So lets say for example that you were really interested in playing a four chord progression based around Bm. Well if this was in standard tuning our Bm would start on the 7th fret of the low (6th) string.
Obviously, this is not a Bm in open d tuning so we know that we tuned down out bottom string a whole step to get to this tuning, so in order to get to this in open d we would just want to play a whole step higher than normal. So we’d move a full step from fret 7 to fret 9. This way we can reverse engineer the chord when we know the root. And if you think about the other strings we changed, the next string that is different from standard is our G (4th) string which we tuned down a half-step. We now just move a half-step higher on that string as well.
Now we can apply that to an entire progression. What is fun in open d is that for many chords you can just barre the whole neck because the notes sort of ‘collide’ to make a chord all on one fret.”