Did they not also trade for cannon made by the Chinese?I just find it very intriguing that a newer and better way of killing and terrorizing your enemy wasn't more fully embraced by whoever the ruling shogun was at that time.I guess being an isolated island nation who frowned on out side contact would explain it.A cultural isolationism steeped in tradition that saw no need for the weapons of the "barbarians".Thanks for your input guys.
Tito