Really nice looking set!
Maybe it should be clear already and I’m no realizing it, but could you translate the novelties? Wouldn‘t want to put those on a board without knowing at all what they mean..
Skipping keys that don't need translating:
R1: Power/Charge, Insert, Delete
R2: (same except with a blank)
R3: Newline
R4: Katakana, Hiragana, Katakana, Hiragana (they're two Japanese character sets so presumably it would be for switching between them)
R4: Alphanumeric (i.e., ASCII), Alphanumeric, Menu, Function, Function, Alphanumeric
R4: Alphanumeric, Alphanumeric, Katakana, Hiragana, Function, Menu (with Help written small in the corner)