Aside from the six native Japanese dog breeds, Akita, Shiba, Shikoku, Kishu, Hokkaido, and Kai (of course there being other breeds such as the Karafuto and Ryukyu), there are a few breeds that originated in Japan, but were created from western breeds. These would include the Japanese Spitz, the Japanese (Chinese!?) Chin, the Japanese Terrier, and the Tosa.
By Ludivine HOUDAS (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
The Tosa originated in Kochi, and was based off the local hunting dogs, the Shikoku Ken. It was a fighting breed from the start, and still is today in Japan. Many breeds such as Pointers, Mastiffs, Bully breeds, Great Danes etc, were used in the breed's creation. The breed is an evolving breed, with almost no pedigreed dogs, and many breeds still being added to the mix, such as pitbulls. The breed within Japan is smaller on average than the dogs being produced overseas.
While not one of the breeds I'm involved in, I was recently asked to look for a pup for a friend of mine. I'm used to Nihon Ken puppies, and a mastiff type pup was a welcome change. The clumsy cuteness was adorable, and the difference in temperament considerable. Nihon Ken puppies are agile and tend to be very alert to threats, but not that willing to engage them. This little Tosa girl was very guardy from the start, definitely guarded the house, and was focused on threats.
Kochi No Kurozakura aka 'Sakura'
Socialization at the hardware store
Hanging out with my friends
I miss this little (big) girl. I've always loved big dogs, and maybe sometime in the future I'll own another. Here she is playing in my yard with my Kishu Baron, some Hokkaido puppies, and my neighbor's Shiba mix. I try to get as much positive socialization in as possible for the pups that come through my house, so shopping trips etc are very common.