1
Kakunosuke Akiyama: Step-on type tone scale play device. Nep Company, Biebel French & Nauman, October 24, 1978: US04121488 (59 worldwide citation)

A step-on type tone scale play device has a flexible mat within which is arranged a plurality of flexible switch elements in accordance with a tone scale and is adapted to produce corresponding music sounds when marks configured on the surface of a mat to indicate the position of each switch element ...


2
Kakunosuke Akiyama: Music studying device. Biebel French & Nauman, July 4, 1978: US04098165 (4 worldwide citation)

A device for studying music concepts, in which, a teaching sheet having a musical staff entered therein is set under a transparent plate having transparent conductive films disposed corresponding to the lines and inter-line spaces of said staff of said teaching sheet, and by teaching a specific scal ...