About the Bandoneon –
The bandoneon is the instrument featured in most tango orchestras. It originated in Germany and was intended for religious and popular music. Although the bandoneon was extremely popular, it was never produced in Argentina. In the late 1800s , German and, Italian emigrants and sailors brought the instrument to Argentina. By 1910 they were being produced mostly for the Argentine market. 25,000 were shipped to Argentina in 1930 alone. WWII led to an end of it’s mass production. Vintage bandoneons are rare and expensive which has limited the opportunity to learn the instrument.
The bandoneon is held between both hands with a pull and push motion. A given button gives a different note on the push and on the pull. Each keyboard has 2 layouts: one for opening the notes and one for closing. The right and left hand layouts are also different so the musician must learn 4 different layouts to play.
Really, use of the instrument for Tango music has saved the bandoneon from extinction.