How to Train a Tosa

The Tosa’s temperament is marked by patience, composure, boldness and courage. He is normally a tranquil, quiet, and obedient dog, with a calm but vigilant demeanor. With a stately manner and robust build, they were formerly bred for fighting, but are now used as watchdogs.

The Tosa is quietly affectionate with his own family, but may be somewhat aloof with strangers. This breed is also, by nature, watchful of other dogs and may react aggressively to dogs it considers intruders. Overtly aggressive behavior towards humans is uncharacteristic of the breed. Their short, dense coat can be fawn, red, apricot, black or brindle and they can also have white markings on their chest and feet. In addition, Tosas mature slowly and individual dogs may not reach their prime until as late as four years of age. This breed is the largest of all Japanese dog breeds. They are also known as the Tosa Ken, Tosa Dog, Tosa Token, Tosa Inu, Japanese Fighting Dog, and Japanese Mastiff.


Japan has a long history of dog fighting, beginning in the 14th century. On the island of Shikoku, the Shikoku Inu had been unequaled in the Japanese dogfighting arenas before Westerners arrived. Shortly after Commodore Perry’s arrival in Japan in 1854, Japanese dog fanciers and dogfighters began acquiring foreign dogs to cross with their native stock. The Tosa breed was produced as a hybrid of Shikoku-ken and Western breeds after European and Western traders brought their mastiff-type fighting dogs with them.

Indigenous to the Tosa Province (now Kochi Prefecture) on Shikoku, the Tosa was named after the region where they were bred and are sometimes called Japanese Mastiffs, for they are known for their extreme courage and tenacious athletic abilities in the fighting arenas of Japan. The Western dogs used for creating the breed were Bulldogs (1872), Mastiffs (1874), German Pointers (1876) and Great Danes (1924), all of which were used to improve the breed by sequential mating. According to some accounts, Saint Bernards and Bull Terriers were also involved, but it is not known in what years they were used. The Tosa’s established features of stamina and a fighting instinct typically found in Mastiffs may be attributed to the involvement of such breeds.

In Japan, Tosas are the canine equivalent of Sumo wrestlers and are treated with great honor and ceremony. In the United States, the Tosa Ken serves as a companion dog and guardian of the home.

Quick Facts 

Temperament: vigilant / fearless / patient

Height: 21.5 to 23.5 inches

Weight: 100 to 200 pound

Life Expectancy: 10 to 12 years

Foundation Stock Service


Some dogs may be faced with health challenges in their lives, but the majority of Tosas are healthy dogs. Working with a responsible breeder, prospective owners can gain the education they need to learn about specific health concerns within the breed.


The Tosa’s short, dense coat requires little grooming, and the occasional brushing will suffice. Beyond that, the occasional bath will keep them clean and looking their best. Their strong, fast-growing nails should be trimmed regularly with a nail clipper or grinder to avoid overgrowth, splitting, and cracking. The ears should be checked regularly to avoid a buildup of wax and debris, which can result in infection. Teeth should be brushed regularly.


Tosas are, by nature, a rather calm breed, though even low-energy breeds need some exercise in order to maintain a healthy weight and get mental stimulation. Options for exercise could include run time in the backyard, preferably fenced, or being taken for walks. Exercise can also come in the form of indoor activities like chasing a ball rolled along the floor or learning new tricks. Certain outdoor activities like hiking or retrieving balls can provide a good outlet for expending energy, too. Training for dog sports like agility, obedience, and rally can also be a great way to give your dog exercise.


The Tosa responds best to positive-reinforcement training methods because of his inherent desire to please his owner.


The Tosa should do well on a high-quality dog food, whether commercially manufactured or home-prepared with your veterinarian’s supervision and approval. Any diet should be appropriate to the dog’s age (puppy, adult, or senior). Some dogs are prone to getting overweight, so watch your dog’s calorie consumption and weight level. Treats can be an important aid in training, but giving too many can cause obesity. Learn about which human foods are safe for dogs, and which are not. Check with your vet if you have any concerns about your dog’s weight or diet. Clean, fresh water should be available at all times.