Jankó keyboard
The Jankó keyboard is a musical keyboard layout for a piano designed by Paul von Jankó, a Hungarian pianist and engineer, 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.