Starring Shogen, Ronnie Lazaro and Kaho Minami, it is based on a true story that depicts Nao Tsuyama, a disabled athlete who refuses to let his artificial leg hinder his dream to become a professional boxer.

Gensan Punch is an internationally co-produced film made by Center Stage Productions of the Philippines and Gentle Underground Monkeys of Japan.

[8] The film is inspired from the biography of Naozumi Tsuchiyama, a Japanese boxer with a prosthetic leg who went to the Philippines who became known as Gensan.

[9] Gensan is also the nickname of General Santos, a city which has produced numerous Filipino boxers including Manny Pacquiao.

[12] The film did not focus on the technicalities of boxing, instead Mendoza decided to highlight Tsuchiyama's "journey as a disabled boxer".