Fawn Tosa
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Tosa Dog Breed

Other names:
Japanese Fighting Dog
Japanese Mastiff
Japanese Tosa
Tosa Fighting Dog
Tosa Inu
Tosa Ken
Tosa Token

Pronunciation: [ˈtō-sä ]

The Tosa, which is also known as the Tosa Inu or Tosa Ken (both "Inu" and "Ken" mean dog), is a highly-prized dog-fighting mastiff in Japan. The fight itself is ceremonious, and the dogs tend to fight quietly; because of this, the dogs are often called "sumo dogs." In many countries, this breed is considered dangerous, and some countries have even outlawed possession of the dog. Tosas are rare outside Japan. Despite being bred to fight, however, this breed's personality is relatively relaxed.

Tosa Breed Details

These dogs were bred specially for fighting. While a Tosa Inu fight is a unique spectacle, they are still massive dogs whose potential for destruction is great. They are definitely not for first-time families, but they are fine with experienced handlers who have children in the house. Attacks by lovingly raised and well-handled Tosa Inus are uncommon but Japanese Tosas may still be banned in your city (or even country).


  • Highly intelligent
  • Remarkably calm
  • Doesn't bark much
  • Great with children
  • Excellent guard dogs
  • Fine with non-canine pets
  • Few exercise requirements
  • Very loyal to family members
  • Extremely protective of property


  • Very rare
  • Rather expensive
  • Matures very slowly
  • Very high pain threshold
  • Aggressive around other dogs
  • Requires an experienced trainer
  • Must be trained very early, as pups
  • May be illegal in your country, city, or neighborhood
10 - 12 yrs.
20 - 24 in.
120 - 170 lbs
OverallFamily FriendlyChild FriendlyPet FriendlyStranger Friendly
Easy to GroomEnergy LevelExercise NeedsHealthShedding Amount
Barks / HowlsEasy to TrainGuard DogPlayfulnessWatch Dog
Apartment DogCan be AloneGood for Busy OwnersGood for New OwnersIntelligence

Tosa Breed Description

This regional mastiff, which is readily available in Japan but not very frequently found elsewhere, is the fighting dog's fighting dog. Because of the rarity as well as the somewhat singular purpose of this breed, there tends to be a lot of conflicting Tosa Inu information. While there is clearly pain and suffering inflicted, the fights are not like typical dogfights; the men who execute the events spend most of their time controlling the dogs verbally and physically while the dogs sometimes bite, sometimes wrestle each other. These can be dangerous dogs but around people they know, however, and non-canine animals, they don't pose a physical threat unless they have been specifically manipulated.

These are extremely intelligent dogs. They must be trained, but they will listen to their human alphas. While they will regard strangers with suspicion, they rarely attack. They understand their size and power tends to be an able deterrent. Because they are bred to fight quietly, these dogs don't bark much, if at all. They are remarkably loyal to their family, and one of the most protective dogs out there.

Another odd aspect is that they don't need as much exercise as you might think. As they develop slowly, they must be exercised carefully so their growing bodies are not injured; at the same time, they can't be neglected lest their natural desire to be rambunctious gets the better of them. You definitely don't want this huge dog chewing up your house because he's bored!

Tosa Temperament

The Tosa is a breed produced exclusively for dog fighting, but when properly trained and correctly socialized, they are very gentle, loyal and protective dogs who tend to bond closely with family members. They don't bark much, but they are highly suspicious of strangers and naturally aggressive around other dogs. The Tosa Inu temperament is a remarkably calm one, but they absolutely require an experienced trainer as well as a true human alpha at all times.

Extremely early training is essential. Starting as late as a few months can easily allow this dog to be unmanageable when he gets bigger — and these dogs get big! Since they mature rather slowly and usually are not fully grown until about 4 years old, you should be ready for the long work. While they behave well around children, they should be supervised to make sure the children don't play too roughly or, if they are very small or young kids, the dog doesn't accidentally knock them over.

Tosa Health

The Tosa seems to have few, if any, hereditary health concerns. The breed's size, however, does prompt problems. Like any giant dog, there is the possibility of bloat and joint dysplasia. They are also noted to have eye ailments.

As these dogs tend to be expensive, you should be sure to get all the health checks and vet certificates to ensure you have a a properly produced and healthy-as-possible puppy. This, along with proper care and a loving home, should see your Tosa live to be 10 to 12 years old.

Tosa Health Concerns

Below are potential health concerns associated with Tosas.


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About this Article

Authored by:Dog-Learn
Updated:April 24, 2017