Never seen a copy with this printed on the disk .Does anyone have any idea?
it was probably owns at some point by the little "oota" now a salaryman in his 40's ;D
Yeah it's 多田 and probably is a name (maybe Oota or Tada but there are several possibilities). 田 means rice field but is very common in Japanese names.
Prototype disks are usually white, but this disk looks like a normal disk with some handwriting on.