Even in the plate era, if the knight and Samurai stumbled upon each other, would the knight really be plated up, and would the Samurai happen to have their Yari? More probably surely would be a battle between two unarmoured men - ending three seconds later as the Samurai chopped through the knights kneck while being run through by the point of the knights sword...

If they had time to get 'glammed up' as it were, then we'd find the true meaning of the words culture shock...