Hi All
Reading what you guys are saying is a marvel with the knowledge you have and I have only just joined the forum to gain more knowledge on this subject. I am a militaria collector for some years now and own three very nice NCO ww2 katanas, nothing in your league though. But what I will say is with my very first one I purchased the person I bought it off did say to me that gun oil is all I need to wipe sparsely on the blade. I also use it on all my other blades I own, bayonets etc,,, and I have never had a problem with any of them using this method.
Jeff