The C Major Diatonic Harmonica
The diatonic harmonica (or "blues harp") is the world's most-played free reed instrument, with 10 holes containing two brass reeds each — one for blow (exhale) and one for draw (inhale). The C-major harmonica is the standard starting instrument, covering all notes of the C major scale across its middle octave through alternation of blow and draw notes.
Blow Chord vs Draw Fills
When you blow any combination of holes 1-4 simultaneously, you produce a C major chord (C-E-G-C). When you draw, you get D-G-B-D — a G major chord. This clever arrangement is why blues, country, and folk players can play a 12-bar blues (I-IV-V) by alternating between blow (I) and draw (V) positions.
Bending and the Blues Sound
By changing your mouth cavity and air pressure, you can "bend" draw notes flat — this is the signature blues sound. The classic draw bend on hole 3 takes the draw note B down to Bb, A, or even Ab on a real harmonica. Our virtual version plays clean diatonic notes for now; future updates will add bends.