Hairline crack on mune?

[Mikaveli]

I've got a wakizashi that passed Tokubetsu Hozon last year, but on the mune there's what looks like a hairline crack, about 2 inches above the nakago.

 

It's not something that was directly mentioned by the seller, how normal is it / how concerned should I be?

[ChrisW]

Long longitudinal split along the grain of the metal? That's called a ware and they're fairly common in traditionally forged Japanese swords. Not a lot of concern to be had here unless it is really wide or close to the hamon.

For more information: http://www.japaneseswordindex.com/kizu.htm

[DTM72]

I agree with Chris. This is a forging ware'. Being that it is in the mune and is tight in nature, it is not a problem. It is possible that this is the core steel not bonding to the skin steel.

[Mikaveli]

36 minutes ago, DTM72 said:

I agree with Chris. This is a forging ware'. Being that it is in the mune and is tight in nature, it is not a problem. It is possible that this is the core steel not bonding to the skin steel.

Interesting, thanks. I'm still calibrating my expectations with regards to traditionally made antiques.

 

I'm too used to working with billet aluminium and modern steels.

[DTM72]

This may help explain what you could be seeing on the back edge. Examples 4, 5, 6.

 

[Mikaveli]

26 minutes ago, DTM72 said:

This may help explain what you could be seeing on the back edge. Examples 4, 5, 6.

 

That's a bit of a eureka moment...

 

I knew about the different construction types pictured, but it didn't dawn on me that that was something I might see externally! Good shout!

[DTM72]

In types like 5, 6,& 7, you can get ware' on the side of the blade, between the high carbon edge and the medium carbon sides. BUT....depending on how well the medium carbon steel was processed before sandwiching it all together, it too could have a forging flaw mixed in.

[Shugyosha]

It’s not a big deal otherwise it wouldn’t have got higher papers: it’s about as far from the cutting edge as it can be. Trouble is, once you know it’s there, it starts to nag so you need to be happy to turn a blind eye to it. 

[Mikaveli]

17 minutes ago, Shugyosha said:

It’s not a big deal otherwise it wouldn’t have got higher papers: it’s about as far from the cutting edge as it can be. Trouble is, once you know it’s there, it starts to nag so you need to be happy to turn a blind eye to it. 

I don't mind it... Too much. 🙂

 

The main thing that keeps me awake at night is the thought of the condition getting worse in my care. 🙈 So as long as I'm not missing any crucial care / maintenance requirement, I'm happy enough.

[ChrisW]

The only way it'll get worse is if you have the blade polished.

[Shugyosha]

I had a blade with a worse mune ware than that. I made a point of using a little oil just to make sure that no moisture could get in but beyond that, it shouldn’t be a concern. Mine got no worse when it was in my keeping.