4nin-uchi Mahjong Jantotsu

4 Nin Uchi Mahjong (４人打ち麻雀, lit. "Four Player Strike Mahjong") is an arcade video game about mahjong. It was only released in Japan using the Japanese language.

The player can play against one to three computer opponents using the tiles associated with the Japanese variation of the game. This is also known as the 立直, リーチ (Ready Hand) variation. Spreading to most mahjong-related video games after this one, it has become the most widely accepted form of Mahjong to the Japanese gamer.