|Tough Gaiden: Oton|
|Original run||2004 – 2005|
Tough Gaiden: Oton (タフ外伝 OTON, Tafu Gaiden OTON) is the side story, serialized in Business Jump since 2004.
This is a side story of the Tough series based around Seiko Miyazawa (Kiichi's father) and his brother Kiryu Miyazawa. Many of the same elements of Tough can be found here, such as mixed martial arts and a lot of violence.