Push notes of two and a half row diatonic accordion in G/C +5.

The arrangement of notes on the extra row is the key to the strength and weaknesses of the resulting layout. Some try to strengthen and optimise the home keys of the diatonic rows, perhaps by making them availabe in both directions of the bellows, for example. Others look to extend the chromatic range through more than one octave, or optimise playing outside the home keys. More info.

If you like bisonoric accordions but want to play any kind of music in any key with similar ease, much better chording, much smoother, easier bellows work with less reversals, and you are willing to learn new fingering patterns, you should think about getting an Atzarin instrument!