G'day Gargs,

There are three popular (aka 'folk') instruments that share a common tuning system: the diatonic button accordion (includes the melodeon, which is the most restricted style of squeezebox) - the German (and Anglo-German) concertina and the 'vamper' (eg "Marine Band, &c) harmonica. The tuning scheme, which gives the semi-automatic harmonies that lead to the name "Harmonica" (in German that's the button accordion, while the mouth organ is the mund harmonika)is ... the Richter scheme ... or even ... the Richter scale! The name comes from a German musical scholar ... not the seismologist.

The shared tunings are one reason why those three instruments became so popular in the 19th century. In Australia it was common for kids to play mouth organ ... and - when parents let them handle more expensive instruments, such as Dad's or Mum's accordion or concertina, they were already well on the way to playing them. Cheap (mostly German-made) concertina were often the middle step for players who went on to masterly playing on much more costly English-made concertinas. You missed out on one of ther great folk instruments!

Regards,

Bob