His first credit with Nintendo was in 1998 on Pocket Monsters Stadium, and since then, his work has focused largely on emulators, working alongside Hideaki Shimizu.
He worked on the Wii Virtual Console, as well as the e-Reader NES Series, the NES emulation with Animal Crossing and the GBA's Classic NES Series.
He's also got a credit in Nintendo World Championships: NES Edition:
According to LuigiBlood, Kawase was responsible for preserving the final revision of The Legend of Zelda from a Disk Writer Soft Pak because the master disk was corrupted – which makes him even more of a legend in our eyes.
It was once reported that Kawase got his break with Nintendo following his work on unofficial emulators prior to joining the company.