Please forgive my ignorance, but I am unsure what I have here. I believe this to be a Partizan Pole Arm weapon. Yes, i am holding it upside down. I beleive it to be a ceremonial piece not used for actual combat. It is dulled on both sides of the blade. Any assistance is greatly appreciated as I try to learn what period this would come from. If not Japanese, I apologize. Thank you in advance.