Wicki or Wicki/Hayden Concertina Keyboard Layout

In principle, this isomorphic arrangement of notes constitutes an excellent keyboard layout. In practice, however, it is even more alien to people who play a diatonic instrument or conventional bisonoric layout than the international chromatic layout, in particular the direction of different musical interval sequencies and the large distance between half, or semitone, steps, as well as non-adjacent minor thirds. In this sense, it is probably not a good option as an "upgrade" from a diatonic to a chromatic instrument. A better option would be an Atzarin layout.

The Wicki or Wicki/Hayden layout also suffers from a directional bias. If the keyboard is to be kept fairly compact, several rows of buttons are needed to ascend through the octaves, as octave intervals along rows are very wide. On a concertina type instrument this may have some impact on the ergonomics of the instrument in terms of the position of the wrist rest and how this affects the balance of the instrument in order to acheive smooth bellows technique.

It should be noted that unless a large number of buttons is used, the regular pattern of notes is interrupted by edge effects, where the player must wrap-around to the other side of the button field to find notes. For a more detailed discussion read the last three paragraphs of the section after Fig. 12 of The Wicki System—an 1896 Precursor of the Hayden System.