By Avatar photoShiloh Nevada Last updated: 18th October 2022

Tosa Inu


Avatar photo Shiloh Nevada
Last updated: 18th October 2022

Tosa Inu is an extremely rare dog that originated in Japan. It is a very strong and massive breed that has been designated by the AKC as a ‘working dog’.

This mastiff dog has a big, broad head with a large nose, strong jaws, small, brown eyes, an abrupt stop, and a long, square muzzle. The ears are thin and hanging floppily on both sides of the cheeks. Their chest and feet have small white markings. The tail of these dogs is thick at the base, tapering to a thin end. They have a muscular shoulder, and their face skin and jowls are loose almost like the Bulldogs.

As a ‘dangerous’ breed, this dog has been banned in many countries already, and might be targeted to be banned in several US states.

Tosa Inu Pictures

NicknameTosa Ken, Tosa Tōken, Japanese Fighting Dog, Japanese Mastiff, Tosa Fighting Dog, Japanese Tosa
CoatStraight, wavy, dense
ColorsBlack, brown, yellow, brindle, fawn
Type of BreedWorking, fighting, mastiff, watchdog
Group (of Breed)Crossbreed
Lifespan10 to 12 years
Weight85-200 pounds
Height (size)Large; Male: 24-32 inches; Female: 22-28 inches
TemperamentAggressive, intelligent, loyal, protective, intelligent
Litter Size6-12 puppies
Good with ChildrenYes
Country of OriginJapan
Competitive RegistrationCKC, FCI, NKC, APRI, ACR, DRA, NAPR, AKC/FSS, ACA

Tosa Inu Fight Video


With the country’s long history of dog fighting, beginning in the 14th century, this breed is in Japan as an extremely popular fighting dog for more than 1000 years.

Originating in the latter half of the nineteenth century, the Tosa Inu breed began with the native breed Shikoku-Inu. In 1872, these dogs were crossed with the Old English Bulldog. Later in 1874, it was further crossed with the Mastiff, as also with the St. Bernard, and with the German Pointer in 1876.

In more recent times, it was crossed with the Great Dane in 1924, and later, with the Bull Terrier with the intention of developing larger and stronger dogs.

With more than 5000 Tosa breeders in Japan, it is during this time that Tosa breeding reached its highest peak.

Temperament and Behavior

The fearless tosa inu is basically a quiet-natured, peaceful dog that is protective and loyal to its family. However, it needs an authoritative owner, who would be able to handle it. Without this, the dog might very well end up being aggressive to other animals and dogs, and even humans. The Tosa is not a breed meant for the first-time dog owners.

These dogs make great friends with children. If trained properly, they are gentle and affectionate to its owner. Usually, they are reserved with strangers. They take a long time to grow up. At times, it takes almost 4 complete years for them to be matured. They must not be kept together with dogs of the same size, sex or temperament. Because of its dogfighting origins, this dog has a very high pain tolerance.

Tosa inu is independent-minded that is willful, stubborn, and dominant, inclined to do things its own way. They can make a good apartment dog, provided it gets a good amount of exercise.



Exercise is extremely important for this fighting breed to stay healthy and release energy. Without this, they would become stressed and might display behavioral issues like other large mastiffs.

However, this is not a breed that demands extremely heavy exercise. Only a moderate amount of daily exercise is enough. They make a good jogging companion. Take them out for long walks and jogging every day.


Being a light shedder, this dog needs very less grooming. Just brush them occasionally (at least once a week) to remove dead and loose hair, and to give its coat an impressive glossy look. Use a natural bristle brush for the purpose. You can bathe them every three months, or when it is dirty.

In order to keep away skin fold infections common to such bulldogs, cleaning their facial wrinkles regularly by wiping them with a moist cloth is important.

Health Problems

Like most other large dogs of this size and energy, the Tosa too is prone to bloating (gastric torsion). Hence, be sure to ask for bloating in the line, as also ask about the health history of its parents. Eye conditions and hip dysplasia is common. Ask your puppy breeders to show evidence that the parents have PennHIP and OFA clearances for hips. This is advisable before you plan to own an active and energetic dog like the Tosa.


Begin your socialization training very early, when it is just a small puppy. Ask your friends and relatives to visit you so that your puppy gets used to strangers and have control over such situations. Be enough assertive enough so that you be a dominant presence in your dog’s life.

The natural instinct of the Tosa is to try to be the alpha dog in its pack. For that, you need to be extremely careful to take the lead of its ‘pack’. You should also be well acquainted with the latest training methods. It should also be fruitful if you send your puppy to obedience or professional dog-training classes.

Also, teach your tosa to follow the humans while walking or moving in and out of doorways, since all humans should be higher in the order, in the eyes of the dogs. This is especially important with such large, independent dogs. Rest depends on the owner, how much confidence and firmness he can hold as its master.


Tosa inu thrives on a homemade natural diet. Its diet should consist of lots of fresh meat and bones. Raw meat and bones are best and most nutrition-enriched. In order to avoid bloating, do not let them exercise just before or after their meals. The estimated energy requirement of an average to heavy size (100-150 pounds approx.) tosa inu with normal activity level is 2500-3000 kCal/day. Since your Tosa might develop weak legs with age, because of its body weight, you should administer extra amounts of calcium, vitamins and minerals to its diet. This should provide a good bone development.

Interesting Facts

  • As had been sought after by the Japanese breeders, the typical ‘Tosa Inu’ character should be prudent, calm, quiet, and at the same time, should have consciousness of its own It would only react in case of emergency, and then displaying great courage and peerless vigor.
  • Due to their fighting origins, this breed has a very high pain tolerance. Hence, the owner must keep its pet Tosa away from other excitable dogs because the former will most certainly win.
  • The Tosa inu has often been referred to as the “Sumo wrestler of the dog world”.
  • Although tosa inu has not been recognized by the AKC, it may compete in the club’s companion events such as obedience trials.

One response to “Tosa Inu”

  1. missourisam says:

    I have proven to my satisfaction that a puppy raised on a diet of high protein dog food supplemented by brewers yeast will grow stronger that liter mates without the yeast. Out of a litter of four male pups, 2 being raised with the yeast supplement, and 2 without, the ones on the yeast matured at 4 inches taller at the shoulder and 30 pounds heavier with much better muscle development and much more stamina, and an extended life expectancy, i e, 5 and 7 years longer. This is the second time this has proven to be so, although the 4 litter mates were the most controlled experiment.

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