MacGregor Concertina

Below is my suggestion for a possible arrangement of buttons on a concertina, similar to the Hayden (q.v.) concertina and to the older Wicki (q.v.) system, but with more buttons per row than the Hayden layout.  With this arrangement, it is possible to play in all major keys with a single fingering pattern.  Positions of accidentals vary from key to key, so fingering patterns are slightly different among the minor keys.

There are thirty notes of the left side, with nine repeated buttons for thirty-nine buttons total, and thirty-one notes on the right, with nine repeated buttons, for forty buttons total, plus an air button on the right side.  There is also a twelve-note overlap between the two hands, for a range of four octaves overall, from B' to b".