Image: capo-ble banjo
As I mentioned in Key Dodges 2/2, some top banjoists have D tuning pegs on their banjos, allowing them to change to D tuning in the middle of a piece. Some may retune the 5th string on the fly, too.
Anyway, the G tuning works quite well for the key of D. It works especially well on the capo-ble banjo. You can fret the G 5th string to A when playing a D chord. The other two most important chords in the key of D—A7 and G—contain G.
Banjo styles usually feature accompaniment of the tune with the 5th string and others as available. That’s a big part of the banjo’s appeal.
However, there is a lot of interest in playing unaccompanied melody on the banjo. The standard G tuning lends itself very well to playing melodies in D. There’s a great little lesson on playing the first strain of “St. Anne’s Reel” in D at https://www.youtube.com/watch?v=i4BwfMQVPYo. Take a look.
A player will, as needed, use the 5th string G as part of his/her melody arrangement. A capo-ble banjo goes much farther, as the 5th string can be fretted like any other. In the case of “St. Ann’s Reel,” this means that the melody can be played in D without shifting to a higher position on the neck. My arrangement shows this. Go to the following site, download “cb St. Anne’s Reel,” play it in TEFView. https://drive.google.com/drive/folders/19SdgeHixtx7XZz2TfHeVa5Yw4scPUOyS?usp=sharing
P.S. I’ve researched at least 14 different versions of “St. Anne’s Reel.” None of them is the same as the one my son-in-law sent me. He doesn’t remember where he found it.