I got this board from Yahoo! auction Japan. The board has so many keys that spit out unsual scan code, to use all of the keys you will have to program them with Tipro software or need PS/2 converter with custom firmware.
Its switches are plate-mounted Cherry Blacks, the board is good source of chery switch while its keycaps suck.
album link: https://imgur.com/a/do2zCwt