A dirty cop who discovers Akagi's immense talent while pursuing him after a game of chicken he participated in resulted in severe injuries for his opponent. Afterwards, Yasuoka seeks to use Akagi's talent for his own gain, setting up a match with the Yakuza before, 6 years later, he introduces the Kawada group to a fake Akagi, Hirayama Yukio. Later, he also helps Ohgi set up the match between Washizu and Akagi, and acts as Akagi's partner in Washizu Mahjong.