WW2 Bring-back Kunitsugu Blade Big Issue

[James Sullivan]

Hello, my father had picked up this WW2 Bring-back Katana that is in resemblance to that of a Kunitsugu Katana, the maker is Kyowa, the type is Shobo-Zukuri and the blade is to date the time of around late 1700's to early 1800's. The issue is when we had first received the blade it was in great condition, little grit from wear but the blade overall is in great condition. However my father took it upon himself to apply mineral oil to it as well as this Metal Polishing / Corrosion Polishing material known as "Flitz". Once applied and wiped down he then put the blade inside of the sheath and has been letting it sit on our basement for about 3-4 months. However recently I went to go remove the blade to clean it and now it is showing these signs of white bloches and brown spots. These had just begun AFTER he used those materials on the blade and put it back into the sheath. Currently the Katana is sitting outside of the Sheath. I re-applied mineral oil to the blade however it isn't coming off and I believe it may be a chemical reaction issue.  Attached are before and after photos, the Flitz used and the markings from underneath the handle. My question in particular is what are these bloches and brown marks and is there anything I can do to remove them without damaging the blade? Is the blade permanently messed up? Can this problem be fixed through a professional? Is the Blade and Swoard genuine to the traditional era before WW2? Or is this blade a WW2 era make? Thank you. 

[Bruce Pennington]

Photo turned right-side up:

 

Hi James!  Welcome to NMB.

 

It would help to see a photo of the whole nakago (tang), both sides, and some close shots of the handle (tsuka) and handguard (tsuba) to say whether this is a legit WWII Type 98 officer sword.

 

Others will check the translation and address the stains.  The one time I had a blade polished, I did learn that there are levels of polish that are cheaper than a full polish that probably would clean your blade up.  Don't try to sand or buff the blade as it will really mess it up.

[KungFooey]

Ouch! I see your dad used the Flitz on the tang as well. That's not good.

[moriarty]

Greetings James, 

 

Welcome to the forum,and thanks for posting pictures of your piece

 

As for the spots, I've seen similar effects in other amateur polishing attempts, on top of damaging the blade, these polishing pastes tend to react badly to low-oxygen environments (I.e a tight sheath) 

 

As for the maker, did you confuse Kyowa (享和) as in the historical era? Otherwise, I read the mei as 神田 (Kanda District), possibly the famous Kanda District of Edo. 

[ROKUJURO]

Even in correct orientation, the signature is not KUNITSUGU, if at all Japanese. There is no KYOWA maker, and the shape is not SHOBU ZUKURI, but SHINOGI ZUKURI (with a weak SHINOGI). 

More and better photos (with plain dark background) in magnification are needed to clear that. 

[Shugyosha]

Hi James,

This is a backhanded way of giving you good news, but it looks like your dad ruined a Chinese copy rather than a genuine Japanese sword. As Maurice says, the kanji on the tang are 神田 or perhaps 神由 neither of which chime with signatures of Japanese swordsmiths from the era of manufacture you stated or any other.

[Brian]

Agree, looks like a Chinese fake to me unfortunately.

[John C]

5 hours ago, James Sullivan said:

Can this problem be fixed

James:

Since the blade may be a copy, there is one thing you can try. Acetone (nail polish remover) is good at stripping old oil and varnish. This may remove the stains. Then clean the residue and finish with a light coat of mineral oil. 

 

John C.

[Bruce Pennington]

It would still be good to close shots of the fittings.

[PNSSHOGUN]

Mounts could be original from those photos, not the first time we've seen chinese fake blades bodged together with original fittings.