Jankó keyboard

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.

Furthermore, the use of multiple rows allows the pianist to more naturally follow the contour of their hand and accounts for the different lengths of the fingers.

[2] The configuration retains the colouring of traditional keyboards (white naturals, black sharps and flats) for pedagogical purposes.

American piano manufacturer Decker Brothers put the keyboard into production around 1891, and the Paul de Janko Conservatory of Music was established in New York around the same time.

A year later (in German patent 32138, dated 1 July 1885) the keys became wider and shorter.