Mahjong Cop Ryuu: Shiro Ookami no Yabou ("Mahjong Cop Dragon: White Wolf's Ambition") is a Mahjong game developed by Whiteboard and published by Sega for the Japanese Sega Mega Drive. It was not released outside of Japan, and was one of the earliest Mega Drive games to not be localized or launched internationally.
The game's story mode balances mahjong against increasingly difficult opponents with a basic adventure mode that allows for different dialogue options with various underworld heavies as the titular character gets to the bottom of his latest case. The mahjong games are one-on-one only, a common sight in early mahjong titles where programming a full set of four players (one human, three CPU) was often a hurdle. It was the first game of its type for the Sega Mega Drive.