Kai-ken (also can be called Kai or Kai no Tora-inu) are a native spitz-type Japanese breed of dogs that originated by the district of Kai(currently Yamanashi Prefecture). They are a medium-sized dog that hunted deer and boar.
The distinctive features of the Kai-ken compared to other Japanese breeds is their big ears, slightly round eyes, and most of all, their tora-ge(brindle) fur pattern.
Tora-ge (literally translated as "tiger fur") is the Japanese term for "brindle", a fur pattern of dogs in which there are streaks of a different colour than the base fur colour. Although the Japanese term refers to tigers, the actual patters themselves are not as distinct as a tiger's stripes, and appear in random places. Tora-ge colours accepted for the Kai-ken are:
- Akatora-ge (red brindle) - the base colour is brown, with dark brown or black streaks
- Kurotora-ge (black brindle) - the base colour is black, with brown streaks
- Chutora-ge (brindle) - an akatora-ge with a lot of white on the belly