タフ外伝 OTON―おとん―
Young Jump (Monthly)
Saruwatari, Tetsuya
A side story of the Tough series based around Miyazawa Seiko (Kiichi's father) and his brother Kiryuu. Much of the same elements of Tough can be found here such as mixed martial arts fighting and a lot of violence. (Source: MU) Included one-shot: Volume 1: Tough Gaiden: Kiryuu
