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Mizukage (retempered blade (flaw)) or Utsuri???

Jorgensen

By Jorgensen
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Jorgensen Proficient

Jorgensen

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The other day I was presented a very beautiful 1300cth hira-zukuri katana blade in superb polish and noticed a clearly visible 45 degree line at the beginning of the hamon. Quickly remembering what I have read in several books its a sign of retempered blade and considered a fatal flaw. I told this to the owner of the blade and he pulled out Connoisseurs book from the shelves and the book support this. But - the blade is ubu and have HOZON paper and I was wondering how this is possible, if its a fatal flaw. It suddenly crossed my mind that I have seen this before when talking about utsuri and found what I have read before here: http://www.ksky.ne.jp/~sumie99/utsuri.html. After seeing this blade and the HOZON papers, I have no doubt that I think Mizukage should be (in this case) considered as Utsuri.

 

SO - I would like to ask you - what do you think? is Mizukage signs of a retempered and a flaw - or is it Utsuri??

post-1540-14196932642019_thumb.jpg

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Marius Grand Master

Marius

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@Jimi-san

 

As you have noted, the sword in the picture is a shinogizukuri blade :-)

 

@Jean

 

I'd love to see pics, please (katana understood as a blade close to 60cm nagasa). Again, an opportunity to learn something :-) Would have thought of shorter uchigatana, but longer hirazukuri blades... Very interesting, thanks :-)

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nihonto1001 Proficient

nihonto1001

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Mizukage in and of itself is not a flaw. It is a condition that happens when the blade is quenched. Thus, if the blade is ubu, it may not be an indicator of saiha (retemper), which is considered a reason to not paper a sword.

 

Though similar, I don't think it should be considered the same as utsuri.

 

If your sword is naginata naoshi, and not drastically shortened, the mizukage may not indicate saiha.

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Jorgensen Proficient

Jorgensen

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The blade may perhaps be from 1500's or 1400's. The papers dont tell. Its just the information that was given to my friend from the seller of the blade and the seller has from where he bought the blade.

 

My intention was not to debate the school og age of this blade, but to debate that what is written in books are considering mizukage as sign of retember and as fatal flaw and others say this is wrong and consider mizukage as a kind of utsuri that is brought out at the original tempering process of the blade. Are the books misleading in this subject?

 

So far I think yes.

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Mark Veteran

Mark

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but to debate if a mizukage belongs on the blade or is a sign of retemper we need to identify the sword. If it were a Kunihiro or his school then it may be a kantei point for his work, same with some other groups and schools. To just say here is a sword with mizukage, is it a flaw or utsuri without knowing what we are discussing seems difficult. can you post some clear pictures of the whole sword and a close up of the mizukage so we can see what we are discussing?

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Darcy Mentor

Darcy

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Mizukage is a sign of the last heat hardening (tempering).

 

The issue is when the sword appears to be suriage but the hamon appears to be original due to mizukage.

 

This is what causes the conclusion of it being a retemper... since you can't be suriage but also show an original hamon at the machi without the hamon being reworked.

 

If the machi is ubu (ish) then there is no issue with mizukage.

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Nihonto Chicken Community Regular

Nihonto Chicken

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Mizukage in and of itself is not a flaw. It is a condition that happens when the blade is quenched. Thus, if the blade is ubu, it may not be an indicator of saiha (retemper), which is considered a reason to not paper a sword.

 

Though similar, I don't think it should be considered the same as utsuri.

 

Just for a giggle as an aside, here are some pics of my Showa Shoshinshi Fukumoto Kumemune (same mei as on page 40 of Yumoto) showing an original mizukage, definitely not a saiha. I obtained this piece in rusty original wavy wartime polish, and, using a Lohman kit, repolished it, ironing out the waves. The finish polish wasn't quite as successful as the foundation, but was still decent enough to expose the mizukage, including an island of yubashiri on the tachi ura side (see upper end of first pic). Sorry for the poor cell phone shots, but they're good enough to show the mizukage:

Mizukage1_zpsa200d21b.jpg

 

Note also the dark points coming off the gunome peaks, pointing toward the shinogi. I don't know that I've ever seen this before or an explanation thereof. Somewhat neat for a ho-hum Showato, eh? ;)

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cabowen Grand Master

cabowen

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Mizu-kage (literally Water shadow) usually forms along the line of the air/water boundary when the sword is quenched, at the angle the blade is inserted into the water. If the blade is placed deeper into the water tank so that the air/water interface is into the nakago, then it won't be visible in the polished blade. It has nothing to do with tempering, which is a different process, called yaki-modoshi, done after the original hardening, at a much lower temperature, to primarily relieve residual stress from the quench.

 

Mizu-kage can be a sign of saiha (rehardening) but it doesn't necessarily indicate saiha. As mentioned, some smiths are known to have a visible mizu-kage. When it is visible, you must consider it along with other characteristics to determine if it is original or due to saiha.

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seattle1 Experienced

seattle1

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Hello:

As usual Chris Bowen has given a clear statement of the underlying question related to mizukage, and just to amplfiy it a little I would add that it is best to think of mizukage as, usually anyway, a necessary condition for saiba, but not a sufficient one. As has been pointed out it is not uncommon in Horikawa school blades, particularly those of Dewa Daijo F/W Kunimichi, but it is not always present in his blades. If a suspicion of saiba is raised there are at least a half dozen other indicators that should be checked for, again, none being certain indications: nioi-giri, frosty hamon, hamon set unnaturally high in an older blade that looks much polished down, oddly distributed muneyaki, a burned nakago, a hamon that continues back into the nakago of what appears to be a ubu blade, particularly if it is post-koto, etc., etc.

Another issue discussed was a possible confusion between mizukage and utsuri. If a blade has utsuri, usually those done in a Bizen tradition with a nioi-deki, and if that blade has not been polished a great deal, the utsuri on ubu blades will have to start somewhere and it usually can be seen, perhaps as a discontinuous path, arising from the ha-machi area. It will look very much like smoke rising from a distant chimney and caught and drifted by the wind.

 

Arnold F.

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Grey Doffin Grand Master

Grey Doffin

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Years ago I had an unsigned blade with mizukage that continued on to become bo utsuri. A long time collector and friend told me he suspected sai-ba. Shortly after then I was in Tokyo and got to meet with Mr. Tanobe and had brought along a full length oshigata of the blade to ask his opinion. He told me, "If a sword has bo utsuri it cannot be retempered."

Grey

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cabowen Grand Master

cabowen

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"If a sword has bo utsuri it cannot be retempered."

Grey

 

Did he explain why? I have seen rehardened blades with utsuri-like effects before. Not sure why a blade that is annealed, then rehardened, couldn't produce the same type of steel structures a blade that hasn't been through the cycle once already...There is no metallurgical reason as far as I know....

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