Overview
A concertina is a free-reed musical instrument, like the various accordions and the harmonica. It consists of expanding and contracting bellows, with buttons (or keys) usually on both ends, unlike accordion buttons, which are on the front.
The concertina was developed independently in both England and Germany. The English version was invented in 1829 by Sir Charles Wheatstone, while Carl Friedrich Uhlig introduced the German version five years later, in 1834. Various forms of concertina are used for classical music, for the traditional music of Ireland, England, and South Africa, and for tango and polka music.
Systems
Concertinas are members of a family of hand-held bellows-driven free reed instruments constructed according to various systems which differ in terms of keyboard layout and whether individual buttons (keys) produce the same (unisonoric) or different (bisonoric) notes with changes in the direction of air pressure.
Because the concertina was developed nearly contemporaneously in England and Germany, systems can be broadly divided into English, Anglo-German, and German types. To a player proficient in one of these systems, a concertina of a different system may be quite unfamiliar.
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