One of the oldest and purest of Japan’s native dog breeds, the Kai was given the status of “national treasure” in 1934. An active and athletic hunter, used to running in packs, this dog may settle reasonably well into being a home companion but is not recommended for a novice owner.

Of all the different breeds of Japanese native dogs, the Kai is perhaps the most unusual-looking, and it is still quite rare in Japan. It is on the small side for a medium-sized Japanese dog, almost midway between the medium- and small-sized categories; like the Hokkaido, there is some argument about whether the Kai is too small to properly be called medium-sized. Its most distinctive feature is its brindle coat, known in Japanese as torage, or “tiger fur,” because of which the dogs are sometimes referred to as Tora Inu (“tiger dogs”) or Kai Tora (“Kai tigers”). The coat colors can be divided into three types according to the color and shading of the dark stripes: black brindle (kuro tora), red brindle (aka tora), and medium brindle (chu tora), but black brindle is genetically dominant. 

Puppies are usually born with fuzzy black coats and develop their brindle pattern with age. It can take as long as five years to come in fully after shedding has occurred several times. The black parts of the brindle should be soft black, and the edges of the stripes should not be sharply defined. 

Kai dogs were once used in hunting, and they originally came from present-day Yamanashi Prefecture formerly known as Kai no kuni before spreading to the Southern Japan Alps, and their name comes from their place of origin. The dogs can be divided, depending on the game that they were trained to hunt, into categories of wild boar Kai and deer Kai. 

Kai is thought to have originated in the village of Ashiyasu in Nakakoma- gun in Yamanashi Prefecture. This is a remote and inaccessible village made up of hunting families; its very survival depended on having fierce, intrepid dogs capable of working in small packs, and in turn, the villagers were devoted to the dogs as an integral part of their lives. All these factors probably help explain the high degree of purity of the Kai and the stability of the breed. The Kai has designated a Protected Species in 1934, earlier than any other medium-sized Japanese dog. 

In temperament the Kai, like most Japanese breeds, is a one-person dog: rather than becoming attached to an entire family, it is a dog that tends to be closest to one owner. It is said that if a Kai’s master were ever in danger, the Kai would fight to the death, if necessary, to save him. In addition to its imposing physical form, it has a keen and watchful manner, an inborn ability to work with other Kai in a pack and to guard a home, remarkable alertness, and an indomitable will. However, the Kai is a natural hunters (some Kai are still used for hunting) and should never be allowed off-leash, except in a fenced yard. 

Kai needs firm and loving training by a patient owner. But once a bond of trust is established, the Kai becomes the best companion dog anyone could hope for. To achieve this, the Kai should be exposed to new places and people from puppyhood well into adulthood and taken to training classes. The breed leams quickly and has good powers of judgment: some Kai has been trained as rescue dogs. The Kai may look wild, but it is said to be very good at understanding its owner’s feelings.