What is this flaw called?

[ribendao]

Where the hamon just disappears with just a faint outline remaining. Can it be remedied through a competent polisher?

 

 

[16k]

I don’t think there is a name for it but it means one of three things:

- the sword has been used a lot and the polish is gone. That can be solved by a new polishing

- during tempering, something went wrong and the area isn’t sufficiently tempered.

- the sword is tired and the polishing went past the tempered depth

the last two can be cosmetically corrected by a competent polisher BUT, is will only be cosmetic. They’ll draw a false Hamon line to cover where it doesn’t exist anymore.

If I had to offer a guess, I’d say your blade is tired.

[Gakusee]

Interrupted (partially, fully, whatever) hamon is called “nioi gire”.

 

JP - by now you should know that the Japanese have a name for everything :).

 

When the hamon is gone, it is gone. That cannot be corrected by polishing, which is just a cosmetic procedure. It is actually quite a serious flaw from a functional perspective as the blade there is softer and cannot hold an edge. 
Of course, in war times, they would just retemper the sword perhaps. 

How the flaw came about is a completely different story.....

[16k]

I know “nioi gire ” Michael, but I always thought it was when the Hamon stops and then picks up later making a "hole" in the tempered area. Is it just the same when it disappears at some point never to reappear after? I believe that is the case here.

[Jacques D.]

Tthis kind of flaw is named nioi shizumu , it's when the habuchi becomes indistinct. it is often due to a difference in quenching depth due to poor temperature control or clay layer application.

[ribendao]

Thanks for the replies. This Wakizashi is tired, has many ware, a fukure, rust, and this nioi gire/shizumu. Just trying to decide if I want to get it it polished or not. I think it might have one more left in it. Probably doesn't make much financial sense though. 

[Gakusee]

Shizumi means unclear or indistinct. So any adjective such as Gire (interrupted) or Shizumi that follows the word for hardening Nioi makes the expression or flaw name. 
 

So which one you use depends on the situation, how big it is and what happens around the flaw. 
 

The reasons for this happening are numerous: eg, crappy hardening process (Jacques described that); over polishing (and thus the hamon there disappears - remember that the hamon is a surface accumulation of martensite); or heat treatment (the yakiba being exposed to fire for example). 

[ribendao]

The hamon seems to disappear about 2/3 the way up the blade and continues all the way until the kissaki, but only on one side. The fukure is also in this section of the blade. I think the main problem is from over polishing and poor hardening. I come to this conclusion because the hamachi is almost non existent. Also the Shinogi-Ji on the interrupted side seems more worn down than the other side. Plus all the ware and the fukure would point to poor forging I guess. Either way I feel responsible for the sword now and just want the blade looking nice again.

[16k]

That’s an interesting description which prompts another question for me. If, say, a temper line, different on each side and narrower on one come to disappear through polishing while the other side, wider remains healthy. Does it impact the integrity of the blade? Technically, it is still tempered, right?

[ribendao]

This is a thread on the blade I made a while back if anyone is curious.

[tbonesullivan]

Looking at overall condition, and the presence of that oxidation near where it happens, I would say improper cleaning to remove the oxidation has made the hamon indistinct. Where I work we get a lot of blades that have a nice polish except for these few spots of rust that someone went after and ended up wiping out the polish in one area. It's very hard to make any judgement regarding this considering the condition of the blade.