Wicki-Hayden system
The Wicki-Hayden system is a system for arranging the keys on keyboard instruments . The Wicki-Hayden keyboard offers a number of advantages over the known keyboard systems. Due to their shifted 6-plus-6 arrangement, the same fingering applies to all keys, provided the range of keys allows it. In addition, the keys of the diatonic scale are very close together. The first three tones alternate in rows with the fourth to seventh tones of the scale.
The Wicki-Hayden keyboard is used at the Hayden Duet concertina . A Hayden bandoneon was also made once .
Hayden Duet concetinas are offered with two different keyboards on the left. In one of them, the fingering of the left hand differs from that of the right hand; in the other, both hands have the same fingering: the index finger is a whole tone lower than the ring finger.