As already suggested by someone on one of the sites this could be an Akita Inu or mongrel of one. They are a Japanese breed.

Loook her:

http://www.akita-in-not.de/

go to "vermittelte Hunde" and scroll down to the one called "Bronco". He is black and white, but othewise very similar. See the head, the tail etc.

Best
Ernest