I saw the viking/samurai. My thinking is that it's a tough call.
However, if Japan were in the range of the Viking longboats, history would have been different.
It was a real eye-opener to see the katana be virtually useless against Viking chain mail. From what I have learned, there weren't many katana thrust techniques, probably due to the body makeup of the average Japanese warrior. Also, I don't know how effective that Yuba bow would have been against a Viking shield wall. And that Japanese sword-breaker club (forget the name) was a pretty impressive weapon.