Uchi Mata, originally released in the U.K in 1986 by Martech as Brian Jacks' Uchi Mata, was also released on disk for the Commodore 64 in the U.S. by Mindscape. It isn't exactly a household name today but it was quite an influential game at the time that introduced some notable firsts in gaming.
Uchi Mata was a Judo simulator and the only one there has ever been that I am aware of. It played like other 2D fighting game such as Yie ar Kung-Fu or even, loosely speaking, like Street Fighter II (though obviously more primitive). For the time, it was a very realistic Judo simulator, allowing a number of fighting techniques. Though there are not really different characters with different moves, a wide variety of moves are available to the player (roughly ten). The control scheme is somewhat similar to Street Fighter by Capcom which would be released the following year in arcades. Uchi Mata was also the first game to introduce hidden moves (moves not documented in the manual that you had to figure out yourself).
Uchi Mata was quite realistic but this realism also made it difficult. It was also a bit unpolished in ways. However, for a complex fighting game there's nothing that could beat this at the time and this is arguably the predecessor to games like Street Fighter II and Mortal Kombat.
In addition to the Commodore 64, Uchi Mata was also available in the U.K for the Amstrad CPC and the ZX Spectrum but the Commodore 64 was the best looking of the bunch. While this game was later released as part of a compilation of games, it has never seen a modern re-release. So if you want to give this predecessor to modern fighters a try, you'll have to dust off your old Commodore 64 (or maybe just an emulator), grab the appropriate disk (or disk image) and type LOAD"*",8,1