Hi folks up-till now I didn't realize that bandoneon only works when you expand bellows and you have to always contract them with release valve while bellows of most harmonicas would work both ways. Is there any specific reason for that? Did anyone of us tried playing this instrument? I've been playing accordions and diatonic accordions and that's why curious.

Enjoy the video bellow and note the way bandoneon sounds only while bellows expanded.

Share your experience.

I vaguely recall tinkering with a bandoneon many (too many to think about) years ago. I'm nearly 100% sure that it sounded on both compression and expansion. It may well be that there are variants that work differently, but the one I handled was "bi". Of course, it's also possible that the "bandoneon" that I played was actually a related instrument that was incorrectly identified by the owner that let me have a go at it.

I often heard Piazzolla contracting bellows with no music only using release valve and than continue playing as well.
Re: Piazzolla,

That may be true, but I'm pretty sure that some Bandoleon/Concertina designs sound different pitches for the same fingering on expansion vs contraction. If a given bandoleon works that way, the player may desire to sound only on expansion to optimize fingering. IOW, that may have been a choice for Piazzolla, rather than a limitation of the instrument.

A quick glance at Wikipedia offers little to no help. There seems to be endless variations on the design of these instruments - as near as I can tell from the entry there.
I actually figured. Bandoneon will sound the same button different contraction vs. expansion of bellows making it playing both ways pretty darn difficult