Read Richard f Stratton s first book .3 pitbulls went over to jap and won ..I was stationed in jap for 2 years .the tosa can't compare to a pit ,I would say a old 40 lb pit of average mouth ,and ability ,and heart will come out on top.not saying that a lesser quality bulldog would have a chance.
Here is another point why are the japs buying american pits ?