The only europeans that were allowed to trade with the japanese following the expulsion of all christians were the

The only Europeans that were allowed to trade with the Japanese following the expulsion of all christians were the Dutch.

During the Sakoku, the isolationist foreign policy of the Tokugawa shogunate, the only contact with european influence allowed was with the Dutch who had a factory at Dejima in Nagasaki, and through the Dutch East India Company who was allowed to operate in Nagasaki.

I think Dutch is the correct answer