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Tosa Inu: Temperament, Origins & Care – A Guide to the Japanese Fighting Dog

Envision a dog as a massive Sumo wrestler and you’ll probably have the Tosa Inu. The fact is, the Tosa dogs share many similar characteristics with this professional Japanese wrestler.

It fights, remains quiet unless spoken to and is always alert. During ceremonies, it also wears regalia with pride, as would a decorated fighter. In light of these traits, how can you not expect this canine to be aggressive?

Size does matter, especially when combined with powerful jaws and scissor-sharp teeth. The Tosa Inu comes across as intimidating, both physically and mentally. Add aggression to the list and you’ll have a dog eager to jump into a fight.

In fact, a Tosa can battle for hours at a stretch without uttering as much as a peep. It is, after all, blessed with amazing stamina that few species can match. Chances are, the Tosa wins.

Many regard this aggressive behavior as extremely unnerving. This explains why as many as 14 countries around the world, such as the UK, Denmark and Australia, have banned this dog breed. The US has not officially banned them, but having a Tosa around could lead to several legal and home insurance problems.

That being said, the Tosa Inu still inhabits Japan – although relatively rare. Overall consensus in Japan regarding the Tosa remains mixed. Some breeders have been making an effort to bring out the positive characteristics, while others breed for the biggest baddest fighters.

By itself, the Tosa Inu is an extremely intelligent dog breed, and once trained, becomes a dedicated member of the family throughout its life.

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Japanese Tosa Basic Profile

Friendliness: The Tosa Inu is not a very friendly dog and can be downright aggressive without proper socialization and obedience training. Even with years of training, they can still show hostility towards other dogs and people. For this reason, they should be the only pet in the family and small children should not interact with them (especially without close supervision).


Trainability: These dogs are not recommended for novice owners because they are difficult to train. The problem is not their intelligence, but rather their stubbornness. They won’t receive training well unless they’re getting it from their pack leader/master. To gain their respect as the leader is another difficult task.


Grooming: A Tosa Inu doesn’t require too much grooming. They shed very few times a year and have a short coat that really only requires seldom brushing. The basic grooming necessities such as nail clipping, tooth brushing and occasional baths are still necessary.


Adaptability: These dogs can’t be locked up in an enclosed environment for a very long time. They are prone to exhibiting destructive behavior if they are. Plenty of space is required for them to run around and ‘patrol’ their territory. Don’t expect your Tosa to easily adapt to unfavorable living conditions.


Activity: All Tosa dogs should receive daily exercise. Despite being a big powerful dog, they don’t require as much physical activity as other big dogs. Still, it’s important for them to have an outlet to expend their energy. A walk or light jog with your Tosa Inu will suffice.

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<strong>Tosa Inu - </strong><strong>Vital Stats</strong>
  • Height: 20 – 32 inches
  • Weight: 83 – 200 pounds
  • Life Expectancy: 10 – 12 years
  • Dog Breed Group: n/a

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Tosa Inu Highlights

Not everything about the Tosa Inu is frightening. Here are some highlights that’ll hopefully put a positive light on this unique dog breed –

  • Their most common nickname is the Japanese Mastiff, which makes a lot of sense because of their size and origins. Other names include Japanese fighting dog, Tosa Dog, Tosa Ken, and of course the Tosa Inu;
  • This canine towers at a height of 24 inches and weighs between 83 and 200 pounds on average. Their weight plays an instrumental role in the Tosa being classified under the light, middle or heavyweight fighting category;
  • The Tosa Inus that are bred in USA are bigger and heavier than their Japanese counterparts. An American Tosa male could weigh between 120 and 170 pounds, which is much more than a Japanese Tosa that weighs between 66 and 88 pounds. Even an American female Tosa Inu is heavier, weighing between 90 and 140 pounds.
  • The average lifespan for a Tosa Inu is 10 years. At the maximum it can stretch to 12 years but most likely not beyond. Reasons for this short lifespan are explained as inherent health issues, with the most common being bones and cancer. 
  • Many countries around the world have banned this dog breed, so make sure your residential country is not among them. Other countries require you to have ownership rights if you wish to own a Tosa Inu.
  • The Tosa Inu’s small dark-brown eyes give a serene expression that could not be more contradictory to its muscular and athletic physique.
  • The Tosa Inu’s coat feels coarse and hard. Color-wise, it ranges anywhere between black and red to fawn, apricot and brindle. At times, white patches appear on chest and feet, but these are more of an exception than a rule.
  • With a lot of excess skin, it appears as though the Tosa Inu might be frowning all the time. However, this canine does not need to frown and the extra hanging skin comes in handy during a bout.

Tosa Inu Origins

The Tosa Inu you see today is a cross from many different European dog breeds.

The Tosa Inu hails from a Japanese province of the same name. Currently known as the Kochi Prefecture, this remote province occupying the southern part of Shikoku Island served as home for this dog breed for as long as historians can remember.

Ultimate Japanese Fighting Dog

Most historians trace the origin of this breed back to the 14th century. Dog fighting as a sport evolved during this era and the Tosa Inu found itself at the center of the act.

To their credit, they adapted well to the sport and its rules. For example, one such rule entailed remaining silent during the fight. Till this day, members of this dog breed seldom bark, whine or whimper.

Initially, the Akita Inu (another Japanese dog breed) was regarded as the premier fighting dog breed in Japan. This changed with the arrival of Commodore Matthew Perry in 1854. The sea-faring admiral introduced several Western breeds, such as; bulldogs, mastiffs and Great Danes.

All of which, were crossbred with the indigenous Tosa Inu. As a result, the hybrid turned out to be the gold standard of fighting dogs. They had courage, tenacity and athleticism. Cross-breeding not only improved the fighting abilities of the Tosa, but also made them superior to the Akita.

Despite the majority of the population moving on from the enjoyment of dog fights, some parts of rural Japan still indulge in this sport. The Yakuza, namely the Japanese mafia, still organizes tournaments that often feature the Tosa Inu.

Downfall of the Tosa

During the 1920s to 1930s, the Tosa reached the pinnacle of its popularity. However, over the years, people began to fear its dominant and belligerent characteristics. As a result, several countries around the world banned this breed while others enforce strict laws pertaining to its ownership.

On the other side, there are animal rights organizations that have raised objections. Their primary goal is to put a complete stop to this inhumane sport of dog fighting. They hope to improve the world’s perception of the Tosa Inu by showcasing their more positive traits.

Hopefully one day, the stereotype of the Tosa as strictly a fighting dog will be eliminated.

Tosa Inu Temperament

A Tosa Inu that is fully socialized and settled-in with its family comes across as calm and laid-back. But to reach this stage, the pack master (you) must be an authoritative person with good leadership skills. Only then will the Tosa Inu pledge its loyalty and protect you against all elements.

That being said, it will still remain wary of strangers. When a Tosa Inu grows suspicious towards an unknown person or animal, there is no limit to the fury with which it can attack. In such a situation, only a firm pack leader can step in and dissolve the tension.

After having acquired a Tosa Inu pup, immediately begin establishing yourself as the indisputable leader of the pack. Next, start training your dog to be social and obedient.

Many owners suggest training with consistency and without using force. This way, your Tosa will have a chance at developing into a gentle and affectionate dog. It would be conscious of its strength and when and how to use it.

If you are not firm from the very first day, a Tosa could certainly start believing that it is the leader of the household. If this happens, then it’s only a matter of when the Tosa will start exhibiting aggression towards family members.

Even after adequate social training, do not leave your Tosa alone with strangers. Always keep them on a leash, even when you take them out for a walk.

With Other Dogs and Children

Compatibility is something that this canine is unfamiliar with. Coming from a lineage bred to be independent and fierce, they need to be taught how to co-exist with others. Therefore, social training should begin as early as possible. Socialization with both humans and dogs is necessary.

And even despite all the social training, a Tosa Inu will still find it difficult to not lunge at another dog. Their natural instinct is to hunt down anything that moves, small or big. For this reason, make sure that your Tosa the only pet in the family.

Likewise, other dogs/animals in the neighborhood should maintain a safe distance at all times. They must also avoid doing anything that can aggravate a Tosa. With that said, it’s probably not a good idea to bring your Tosa to your neighbor’s BBQ.

Children in the family should be taught how to behave with this canine. It has a strong sense of loyalty, but even a bit of rough play can trigger the wrestler instinct buried deep within. Because of this, it’s best not to have small children around a Tosa until they are old enough.

Tosa Inu Care

Caring for a Tosa Inu entails certain dos and don’ts. To care for your Tosa, you must –

  • Ensure that it receives light to moderate exercise every day;
  • Provide it with a fenced yard where it can run around and enjoy the outdoor without being distracted by other animals;
  • Take it out for a jog/hike every once in a while;
  • Let it remain at home with the family;
  • Use positive reinforcement methods to train and teach;

What you must not do with a Tosa Inu is –

  • Chain it to the fence or confine it to the kennel with little or no interaction with the family;
  • Allow it to get bored, because a bored Tosa will easily become destructive;
  • Let it chew everything in house, or soon you will have virtually nothing left;
  • Expect an electronic fence to restrain it because it will hardly make a difference;

Tosa’s Diet Guide

At all stages in its life, feed the Tosa Inu high-quality canine food. Get a brand which has formulated options for large breeds and ensure that it matches with the age of the canine.

Initially, the Tosa pup may take its time to grow. In such a situation, continue with the pup formula for longer than usual. Some owners suggest until it is one year old.

Tosa Inus love treats. Use them while training your canine, but in moderation. Too many treats could lead to obesity and addiction. Select a treat that your canine loves, and ensure that it is always available at home.

You can serve human food to Tosa Inu, but not all types. Find out which type of home-made food would suit it best. Then work out a balanced meal plan, add some variety and follow it on a daily basis.

You can even use fruits and vegetables as treats, but make sure your dog can safely eat them first. Always maintain a bowl of fresh water round the clock, as the Tosa’s well-being depends on it.  

Grooming the Tosa Inu

Grooming a Tosa Inu involves a few routine tasks, such as –

  • Brushing the short, coarse and dense coat will ensure removal of dead strands and provide a neat look. This breed does not shed as much, so you need not be concerned about this aspect. Brushing once or twice a week will be sufficient.
  • You can bathe the Tosa once in a while to wash off all the deep-seated dirt and grime.
  • Like all mastiffs, a Tosa Inu also drools – a lot. Although they drool less than other species, you are bound to find puddles of slobber all over the house. Counter this problem by maintaining a round-the-clock supply of baby wipes to wipe it off before it dries up.
  • Invest in a strong and sturdy nail clipper that would effectively trim strong dark nails without causing them to split or crack. A Tosa’s nails grow very fast and should be trimmed regularly. Get your Tosa pup comfortable to nail trimming from a young age by trimming a small portion at a time. This also reduces your dog’s chances of injury.
  • Brush your Tosa’s teeth regularly to prevent dental issues. This is especially necessary if they eat a lot of human foods and treats.
  • Check your dog’s ears every now and then for wax, debris and other foreign particles. These can cause ear infection if not removed at frequent intervals.

Establishing Dominance

Dogs in general carry a ‘pack’ mindset. So when you bring home a dog, you and your family automatically become its pack. Every pack follows one leader, which could be either human or canine.

The Tosa Inu takes this system rather seriously.They will willingly take over the duties of a pack leader if they feel others around are incompetent. Once that happens, be prepared to witness a Tosa unleash its full fury of dominance.

To avoid this situation, establish yourself as the indisputable leader of the pack. Make it clear that everyone, including the Tosa, should do your bidding and be consistent with rules. This is key to earning the canine’s respect and unflinching devotion.

Keeping a Tosa under firm control is imperative because members of this dog breed react instinctively towards anything that moves. Whether it is a bird, a cat or the neighbor’s child, a Tosa Inu is prone to attack. Only a respected ‘pack leader’ can avert a disaster.

Tosa Health

The majority of Tosa Inus enjoy good health. At the same time, you cannot turn a complete blind eye to some congenital health problems. Selective and cross breeding programs have taken their toll on the health of the Tosa in specific ways.

As a prospective owner of the Tosa Inu, you should be aware that your massive dog may be prone to these health problems: 

Skin allergy – The Tosa Inu tends to suffer from skin allergy. Irritants responsible for causing redness could range from food to pollen, dust mites and so on. As soon as you notice the first sign/symptom of skin allergy, take your canine to the vet. Do not ignore this as it could aggravate into an infection. Before it becomes a nightmare, try to identify the cause and begin treatment.

Dysplasia of elbow and hip – Large canine breeds usually have joint related problems. Abnormal growth in joints, especially elbow and hip, cause developmental issues that lead to pain. Over a period of time, it could also result in your canine limping due to joint pain.

Check the Tosa’s ancestry for these issues prior to getting one. This condition is usually genetic and it is bound to reflect in the certificates of both parents. It’s best to opt for a Tosa that is free from this hereditary issue. Yet, another reason to find a reputable breeder for your dog.

Hyperkalaemia – Mostly benign, this medical condition can sometimes surface in the form of spiked potassium levels in the blood. Do not feed your Tosa dog onions and garlic, which can drastically worsen this condition. In case it becomes too lethargic or you observe irregular heartbeats, seek immediate medical attention.

Hypothyroidism – A lack of thyroxine causes the Tosa to gain weight and shed its coat. You may confuse this condition with a skin allergy, but they are different. If you observe symptoms of this condition, subject your dog to a comprehensive health check-up that also examines its thyroid gland.

Bloating – Always guard against bloating if you have a Tosa at home. Also known as gastric torsion, it can threaten your canine’s life if not handled properly in a timely manner. As soon as you observe symptoms, take your Tosa Inu to the vet and get its tummy straightened out.

Final Thoughts

A Tosa Inu is what it is meant to be – aggressive and powerful. So, you are the one who needs to decide whether or not this breed is for you. If you happen to be a first-time dog owner, then go with some other dog breed.

With a Tosa, you will have a tough time without proper experience. Since they aren’t a “dumb” dog breed, they will quickly pick up on your lack of confidence and experience. Much to your dismay, the Tosa will appoint itself as the leader rather quickly.

Owners often complain about the Tosa Inu having behavioral problems. In all honesty, this dog breed has been cultivated as such. Under these circumstances, it is a little unfair to blame this canine for something that is a part of its constitution.

Rather, subject yourself to an honest scrutiny. Can you establish yourself as a leader of the pack and take charge without relying too much on force? If yes, then by all means raise a Tosa Inu and look forward to being a proactive pet owner.

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