Ryuu, also known as Crying Dragon, is a mysterious man who often plays mahjong with gang members. He only wins by "ron" - a move in which one needs to wait for the opponent's tile to complete the win.

Source: MAL

Note: "Ron" is also called "naki" in mahjong, which has the same pronunciation as "crying" in Japanese.

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Alternative version: Mahjong Hishouden: Naki no Ryuu - Hiryuu no Shou