Josef Hofmann

He was not only a highly acclaimed pianist, respected by the likes of Rachmaninov, but also a keen inventor. He had powerful but small hands and in this video he is playing the smaller keyboard with which he concertized in the 1930s and 1940s.

What Size Keyboard?

In the overhead views of this video the bass filler block, which takes up the extra space in the piano, can be seen. The size of the keyboard's octave is 6.25 inches. To understand what this means see: