A complete 'revised' Ketsui EPROM for your CAVE board.
Ketsui's original software release has some bugs -- most notably, the freeplay bug where sometimes when you start a game, the attract mode demo controls take over your ship and fly it in an unpredictable fashion, quickly dying 3 times, going to a game over screen, and freezing up your board. If you wish to swap the EPROM on board with a revised chip, this is the one to do it with. Keep your original Cave-labeled chip for completeness, but put this one on board to avoid the bugs in the original release.