Jankó keyboard

The Jankó keyboard is a musical keyboard layout for a piano designed by Paul von Jankó in 1882. It was designed to overcome two limitations on the traditional piano keyboard: the large-scale geometry of the keys (stretching beyond a ninth, or even an octave, can be difficult or impossible for pianists with small hands), and the fact that each scale has to be fingered differently. Instead of a single row, the Jankó keyboard has an array of keys consisting of two interlocking manuals with three touch-points for each key lever. Each vertical column of keys is a semitone away from its neighboring columns, and on each horizontal row of keys the interval from one note to the next is a whole step.