Dog fighting has been a popular spectator sport in Japan, as it has been in the rest of the world, although in a significantly different form. The tradition of dog fighting runs especially high in the Tosa district of Shikoku, with fighting seemingly dating back to the Hojo era, as was mentioned in the ancient document, the Tai-Heiki. Centuries ago the Japanese used dogs from the northern regions which were the predecessors of modern-day Akitas, as they were valued for their courage and tenacity. "So valued were these attributes that organized dog fights were used as training sessions for Samurai warriors in order that the Samurai might learn by observation the true meaning of courage." (Semencic, Carl. "Introducing the Tosa-Inu of Japan." Dog World, Sept. 1983.)
Tosa fighting is very similar to Sumo wrestling, and follows similar rules. Led to the fight by silk ropes, the Tosas wear embroidered ceremonial robes which can cost $30,000 or more. The two dogs are placed (robe-free) in a gazebo-shaped ring ten feet in diameter in the presence of a chief judge, two assistant judges, and three or more examiners. The dogs lock heads and attempt to push each other out of the fighting area. No sanctioned Tosa-Ken fight is to the finish. The time limit is 30 minutes and typically the fights last no longer than ten minutes. Any barking or growling disqualifies the dog. The winning dog is not necessarily the one to attack more often or more viscously. Victory depends solely on the spirit of the fighter. If a dog has been dominated by the other dog for the entire duration of a fight, the winner still has yet to be decided. Failure in the fight is decided if the dog whines, groans, or gives up by attempting to run away from the other dog or due to sheer fatigue, is unable to get up again.
Approved fighting is between male dogs only. Although females are extremely brave when compared to other breeds. Tosa-Ken females are typically used as home guardians. Like any sportsman, the male is placed under a strict living regimen and is regularly exercised. That consist of up to 10 miles a day. At most, the dogs are scheduled for two or three fights per year. The most successful dogs are given the rank of "Yokozuna", the title given to a champion in Sumo wrestling. The Tosa-Ken Dog Fighting Center in Kochi displays pictures and many materials which document the history of the Tosa-Ken. The center also maintains a showcase of the present Yokozuna (grand champion), Ozeki (second highest rank), and other high ranking Tosa-Inu's.