Tsutomu Kato (1926–2011) co-founded Keio Electronic Laboratories — later Korg — with Tadashi Osanai in 1962.

Kato operated a nightclub in Tokyo when Osanai proposed building an improved rhythm machine. Their 1963 DoncaMatic DA-20 was Japan's first domestically produced drum machine and launched a company that would become one of the «big four» Japanese synthesizer manufacturers.

Kato steered Korg through the MS-20 era, the Polysix, the M1 workstation revolution, and participated in early MIDI standardization alongside Ikutaro Kakehashi and Dave Smith.

Notable products: Korg DoncaMatic, MS series, Polysix, M1 (company leadership).