The Kodo-kai is a yakuza criminal organization based in Nagoya, Japan. It is a secondary organization of the Sixth Yamaguchi-gumi, the largest known yakuza syndicate in Japan. With an estimated membership of 4,000, it is the second-largest Yamaguchi affiliate after the Yamaken-gumi, and operates in at least 18 prefectures.

Yakuza , also known as gokudō , are members of transnational organized crime syndicates originating in Japan. The Japanese police and media, by request of the police, call them bōryokudan , while the yakuza call themselves ninkyō dantai . The English equivalent for the term yakuza is gangster, meaning an individual involved in a Mafia-like criminal organization.