The Harmonica Company: Harmonica in Key C
The key of C major is the key in which the greatest proportion of Western music is written, and is, therefore, usually the first key of harmonica to own.
It is generally thought of as the simplest key in which to play, as it includes no sharps or flats – just the notes C, D, E, F, G, A, B, which on a piano keyboard, for instance, is all of the white notes.
The second position of a standard C major diatonic harmonica is G, which is another popular key for harmonica players.
Most 14 and 16 hole chromatic harmonicas are available only in C.