Country of OriginJapan
Nicknames and Other NamesTosa Inu, Tosa Ken, Japanese Mastiff,
Tosa Fighting Dog, Japanese Tosa
Scientific NameCanis lupus familiaris
Breed TypeCrossbreed
GroupGuardian Dog
Bred ForDogfighting
Recognized ByAKC, UKC, FCI
Life Span10-12 years
Ideal Weight100-200 pounds (male and female)
Ideal Height21.5-23.5 inches (male and female)
Fur TypeShort and smooth
Common ColorsRed, Fawn, Black, Brindle
MarkingsWhite markings
AvailabilityModerately available
Suitable for ApartmentsNo
Used in World WarNo
Most Similar ToBoerboel

Tosa, which is also known as Tosa-Inu, Tosa-Ken or Japanese Mastiff is a large-sized dog. It is not a dog for an inexperienced or a novice dog owner as it is best suited for an experienced owner who knows its needs and behavior. If you need a calm but confident dog that you can make a good effort to train them and raise them, it is for you.

The Tosa is a large and powerful dog with a strong and muscular body. It has a large and board head with a square muzzle. Its jaws are powerful and have large teeth that are scissor bite sharp. The ears are set high on the head that hangs close to the cheeks. Their feet are large and bones are heavy, which makes them very strong.

Origin and History

The origin of the Tosa was on the island of Shikoku at the place called Tosa Wan in Japan. Its written record was found which proves that it has been in Japan for over a thousand years. It was bred to use for dogfighting in the ring.

Tosa is believed to be developed by crossing western breeds like German Pointer, Bull Dogs, Mastiff, and Great Danes to increase its strength, power, and size. Tosa becomes renowned for its fighting ability.

Tosa History
Tosa standing.
Image Source: akc

Tosa is still treated with great honor in Japan as a fighting dog. However, in the United States, it is kept as a guarding dog and family companion.

The United Kennel Club recognized Tosa in 1998 under guardian breed. The American Kennel Club has kept this breed in the Foundation Stock Service since 1997 (as of April 2019).

Is Tosa Child-Friendly?

Tosa is an excellent companion for big children if they are raised together but kids should be taught to be gentle and friendly towards them. They are not best suited at home with small children due to their large size. They might knock over them accidentally and hurt them.

Tosa walking with a girl
Tosa walking with a girl.
Image Source: pinterest

Temperament, Behavior, and Personality

Temperament: The Tosa has a fearless and vigilant temperament. They are very watchful and alert of the activities going on in the surrounding. Therefore, they make a great watchdog and guard dog. They love their family and are very much attached to one particular person whom they see as a leader. They are fearless and cross any line to protect their people.

Behavior: Tosa is known as a fighting dog but they have a docile nature and are not as aggressive as they seem. They need to be socialized at an early age and expose them with a variety of people so that they are well-behaved around people.

Personality: Tosa has a docile personality and is a very patient dog. It is wary of strangers but is not usually aggressive. Tosa is very peaceful and devoted towards its family members even though it is considered as a dangerous dog. Therefore, it is a fearless protector of the family.


Training Tosa is not a hard job for an experienced dog owner who knows dog behavior and temperament. They need a leader who can guide them with firmness and consistency. Do not be harsh on them as it can lead to their aggressive behavior.

Train them gently and use positive reinforcement as a motivation for training. Reward them with delicious treats and vocal praises.


  • Tosa has been assigned to the Working Group destination in the American Kennel Club.
  • During World War I, it almost got extinct but luckily its fancier work on to save this breed.
  • There are certain areas in Japan, where Tosa is not allowed because it is considered as a dangerous breed.
  • Tosa is even banned in some country and some require a special permit to own this dog. Like in the United Kingdom, it is illegal to own Tosa without a permit from the government.

Health Issues

General Health
Common Health Issues
Vaccination Required
Weight Gain Potential
Separation Anxiety
Diets and Supplements

Tosa is usually a healthy breed with a life expectancy of 10-12 years on average. However, during these years, they might face some health situations, which are explained below:

  • Bloat: Bloat is in a large-sized dog-like Tosa. It is caused due to overfeeding, less exercise, and improper eating habit. The symptoms are the distended abdomen, restlessness, vomiting, and so on. Consult a doctor if certain symptoms are seen in your dog. Offer them water all the time, feed them little meal several times a day, and avoid dry kibbles.
  • Hip Dysplasia: Tosa might suffer from hip dysplasia due to its large size. It is caused due to underdeveloped or dislocation of the hip joints. It causes sharp pain on the back of your dog if it gets serious. Therefore, it is recommended to take your dog to a vet for a consult and the required treatments.


The Tosa comes in following colors according to American Kennel Club:

  • Black
  • Brindle
  • Fawn
  • Red
  • White markings


Height and Size: The average height of the Tosa is between 21.5-26.5. The average weight is between 100-200 pounds.

Cost: The average cost of the Tosa puppy is between $600-$800 USD.

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