Not a signature but a stamp I have never seen before

[Cuirassier]

I suspect it is a post-WW2 blade but have no idea.

Not sure about it at all.

Any help?

Cheers

[DTM72]

Sorry, but this appears to be a Chinese blade. The number "1" on the habaki is also not traditional Japanese. Lastly, the top of the tang, just above the stamped character, but below the habaki, looks to have been welded/fused together. Overall the nakago (tang) is poorly finished. Sorry to be the bearer of bad news.

[Brian]

Yip, agree

[Bruce Pennington]

This seems to be coming from a particular sword maker or faker.  Chances are that it's a faker.  The nakago quality are all the same poor workmanship.  But using various stamps:

 

[Cuirassier]

Thanks guys. Appreciated.

[Kiipu]

Cross-Reference

Stamped numbers on habaki