In response to the opening post, concertinas were primarily intended to play 'voice' parts in concertina bands, hence such names as treble, tenor, baritone, bass and contrabass for different models. Many people still use them as single note melody instruments - as do a lot of Anglo players.

Don't forget that Wheatstone originally intended people to be readily able to play from written music, with the 'line' notes on the left and the 'space' notes on the right.

Music for the masses!

They were also intended to be played whilst seated, supported by one knee - the Salvation Army were famed for making inventive adaptations to facilitate playing whilst marching.