I presume that this patent number was registered in Japan, given that the US patent is for a "wheel for scouring or buffing". Not a suitable application for an SB methinks.
Has anybody got the abstract for this? It would be interesting reading and fantastic for poster(ior)ity.
I did manage to dig these up as registered by Uncle Matsumoku Kogyo Kabushiki Kaisha:
"Electric Guitar" (PE?)
http://www.google.co.uk/patents/about?id=iVM7AAAAEBAJ (invented by Nobuaki Hayashi)
"Tone Control"
http://www.google.co.uk/patents?id=R8czAAAAEBAJ (invented by Takayoshi Yamagami)