Janputer (also known as both Janpyuuta and Janpyuutaa) is a riichi mahjong (two-player variant) game developed by Alpha Denshi and released by Sanritsu Giken as well as Taito for arcades in Japan on May 1981.
The earliest known arcade adaptation of the tile game mahjong, Janputer (its name a combination of "mājan" and "computer") is a one-on-one version of the Japanese variant with some simplified rules (such as the lack of player winds). It uses a unique time-based system where players have a countdown timer and must attempt to extend their credit (allowing additional rounds) by scoring hands. While it includes two-player multiplayer, both players alternate playing against separate computer opponents.
Due to the game's popularity, it received numerous clones (both licensed and unlicensed). Licensed versions include Taito's T.T Mahjong and T.T Mahjong 2, and Nichibutsu's Taikyoku Computer Mahjong.