Progressions in D — Cello

D major harmonises to D – Em – F#m – G – A – Bm – C#°; D minor to Dm – E° – F – Gm – Am – A# – C. Each chord links to its tone map on the Cello, so a tune in D becomes a short list of places the hand needs to be.

The useful question in a key is which open strings it agrees with. In D, check the chords against the open C and A — a key that leaves an open string ringing under the melody is a key this instrument was built for.