The body screams Tosa, but the head is a bit "soft". It could just be the individual, not every dog is the picture of perfection, or the dog could be mixed with something (Lab would be my guess!)
That tail is really interesting. It's really broad at the base which again makes me think the dog is a mastiff breed, but it's so long.
He is gorgeous, but I gotta ask.. WTF is with the purple bow thingy? That's just, ew.