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(Tosa Ken, Tosa Inu, Tosa Dog, Tosa Token, Japanese Mastiff, Japanese Fighting Dog)
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Form and Function

Formerly bred for dog fighting but now primarily used as a watchdog, the Tosa is the largest of all Japanese dog breeds and is known for having a powerful, hardy build with a regal stature. The Tosa has a board, wrinkly head with a boxy muzzle, high drop-set ears and a tapered tail. His short, dense coat can be fawn, red, apricot, black or brindle, with or without white markings on his chest and/or feet. The Tosa’s appearance gives the impression of a true dynamic athlete and warrior.


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Breed Traits

Energy Level

2 out of 5

Exercise Requirements

2 out of 5


3 out of 5

Affection Level

3 out of 5

Friendliness To Dogs

1 out of 5

Friendliness To Other Pets

2 out of 5

Friendliness To Strangers

1 out of 5


5 out of 5

Ease of Training

2 out of 5

Grooming Requirements

1 out of 5

Heat Sensitivity

2 out of 5


2 out of 5

Breed Attributes




100 to 200 pounds


At least 23 ½ inches (male), at least 21 ¾ inches (female)


Guardian (UKC), Foundation Stock Service (AKC)

Area of Origin


Date of Origin


Other Names

Tosa Ken, Tosa Inu, Tosa Dog, Tosa Token, Japanese Mastiff, Japanese Fighting Dog


With the growing popularity of dog fighting in Japan in the 14th century, Japanese dog fanciers and dog fighters began to obtain foreign dogs to cross with their native stock following Commodore Perry’s arrival in Japan in 1854. These mastiff-type breeds included the Bulldog, Mastiff, German Pointer and Great Dane, as well as the Shikoku, a native to Japan. The breed was named the Tosa for the region, the Tosa Province on the Shikoku Island, in which it was bred and developed. Today, the Tosa is highly regarded in Japan as the canine version of a Sumo wrestler, while the breed primarily serves as a companion and guardian in the United States. The United Kennel Club has recognized the Tosa Ken as a member of the Guardian Dog Group since 1998, and the breed continues to be part of the American Kennel Club’s Foundation Stock Service throughout its further development.


Bold and courageous, yet quiet and composed, the Tosa has a calm and dignified demeanor. He is patient, affectionate and obedient with his human family, making for a vigilant watchdog and wonderful companion. The Tosa is wary of strangers and other intruders, and can be aggressive with other dogs. Training with plenty of positive reinforcement is a must for this eager-to-please breed.


Besides occasional brushing and bathing, the Tosa’s short, dense coat doesn’t require much upkeep. Other regular maintenance includes nail trimming, ear cleaning and teeth brushing. This low-energy breed requires some exercise, such as being taken on a daily walk or being allowed to run freely in a fenced yard.


Major Concerns: N/A

Minor Concerns: N/A

Occasionally Seen: N/A

Suggested Tests: N/A

Lifespan: 10 to 12 years


Note: While the characteristics mentioned here may frequently represent this breed, dogs are individuals whose personalities and appearances will vary. Please consult the adoption organization for details on a specific pet.

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