Concertina

A concertina, like the larger accordion, is a member of the Free Reed family of instruments. Concertinas typically have buttons on both ends and are distinguished from an accordion (piano or button) by the direction of their button travel when pushed. Concertina buttons travel 'in the same direction as the bellows' whereas accordion buttons travel 'perpendicular to the direction of the bellows'. (Ed. Note: the image presented here is -not- a concertina, but rather a single row accordion (or melodeon). Note the direction of the button travel, perpendicular to the bellows travel.).

There are two common kinds:

• The Anglo concertina (from "Anglo-German") has buttons in curved rows following the fingertips. Pushing and pulling the bellows give two different notes from the same button. It is the ancestor of the bandoneon.
• The English concertina has buttons in a rectangular arrangement of four staggered rows, with the short side of the rectangle at the wrist. Pushing and pulling give the same note. A scale in most keys alternates between one side and the other.

There are also various duet system concertinas, which are much more rarely seen than Anglo and English concertinas. Their button layouts provide low notes in the left hand, high notes in the right, with some overlap (like a piano), and the same notes pushing and pulling.

Needless to say, a player of one of these "systems", given a concertina of a different system, will feel like s/he is playing an entirely new instrument.