Shamo (軍鶏, "Gamecock") is a Japanese action manga series written by Izo Hashimoto and illustrated by Akio Tanaka.

It tells a story of a boy who killed his parents and turned himself into a cold-blooded martial artist.

In a beautiful sunny afternoon when cicadas were singing, he stabbed his father and mother to death with a short knife repeatedly before he came to his senses.

Ryo survived and thanks to a law that protects minors, was released two years later, but not before beating several would-be attackers with such savagery that his previous tormentors became terrified of him.

Ryo started to fight for his living and used all imaginable dirty tricks to defeat his enemies.

[citation needed] Believing that he is the strongest, the "gamecock" starts to take on other good martial artists.

A blood-thirsty TV producer notices that this street-fighting young man was the "Youth A" and pushes to have him join "Lethal Fight," a fictional combat arena modeled after Japan's K-1 tournament.

Sugawara vowed to kill Ryo with his hands in the boxing ring to comfort his woman and agreed to a televised fight at the Tokyo Dome.

Ryo goes through a painful bodybuilding regime where he used steroids to increase his muscle mass and strength.

Out of anger and frustration, Sugawara invites Ryo to another private fight three months later in an abandoned temple.

After a long and brutal duel where Narushima is almost killed, Sugawara is hit in the back of the neck and was hospitalized.

Ryo discovers after one fight that his ability has dropped significantly (implied to be due to the experimental steroids he had taken before) and he decides to start training hard.

Ryo enters a Banryukai karate competition in a mask and after losing in the finals by disqualification, is spotted by Mochizuki.

Ryo, desperate for money, accepts and begins training with the master of the man he lost to in the finals (who has since returned to being a hikkikomori).

adapting more quickly to this new field Ryo turns the tables and begins using mind games to overwhelm the more naive Toma.

He hires 2 hit men to deal with Ryo and get his daughter back despite the fact she is there of her own free will.

[3] Shamo manga artist Akio Tanaka was in a legal battle against Shamo's credited creator, Izô Hashimoto, for 150 million yen (about US$1.4 million) in a copyright lawsuit that opened in June 2008 in the Tokyo District Court.