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chunks
13th February 2006, 18:39
I recently purchased two identical katanas. Nothing fancy, but billed as reasonable quality hand forged, folded blades with a "true temper line"
which they call a Yakiba. I thought it was a hamon and I'm not clear on what the difference is.

It would be great if someone could educate me on the difference.

My main question results from the fact that this irregular wavy hamon has
exactly the same shape on both blades. Not nearly. Not close.
They are identical.

Would this indicate that its not a real hamon (or yakiba) but rather one created
through clever polishing?

shinai_swinger
13th February 2006, 23:04
As far as I know, the term "hamon" refers to the pattern the temper line takes. Yakiba, on the other hand, refers to the entire hardened area of the blade (the part composed of martensite on a diff. tempered blade). The transitional area between the hardened edge (Yakiba) and the softer spine is referred to as habuchi. At least I'm pretty sure :) . I have no doubt I will be corrected if I'm wrong.

As for your identical "hamon" question. I'd need to see a pic to be 100% sure, but it sounds fishy. It's pretty common for a cosmetic hamon to be applied with a stencil and a wire brush. This could result in 2 blades with 100% identical (but fake) "hamon". Is the hamon the same on both sides of the blade?

If you could post a pic or 2, that would be very helpful.

chunks
14th February 2006, 13:02
Is the hamon the same on both sides of the blade?

If you could post a pic or 2, that would be very helpful.

I'll see if I can get some pics up tonite.

The hamon is not the same on the opposite side of the blades. In some places the line is quite close to the edge on one side while being much farther in on the opposite side.

Chris

paradoxbox
19th February 2006, 22:00
It is possible for that to happen if clay is very sloppily put onto the blade but from what it sounds like, you've probably got some fake swords. It's pretty easy to polish metal into something that looks like a hamon.

Michael Powell
20th February 2006, 01:06
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I'm inclined to agree with Shinai Swinger and further sense the wave pattern is made by applying clay to a heated sword blade just befor cooling it in water it seems totally impossible to acheive the exact same pattern.

Brian Owens
20th February 2006, 11:55
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...the wave pattern is made by applying clay to a heated sword blade just befor cooling it in water...
Actually, in the traditional process, the clay is applied to a cold blade and allowed to dry completely.

Later, the clay-encrusted blade is heated in the forge, and then quenched.

Since the tempering process requires heat-soaking the blade to a red-hot temperature, it would be virtually impossible to apply a slurry of water and clay to it. The slurry would explode on contact.

tddeangelo
20th February 2006, 22:23
This has been observed (exacting symmetry in the hamon) on production swords in the past. No conclusive explanation has been offered to my knowledge, although consensus seems to be that a stenciling technique is used to apply the clay, but the hardening process is authentic.

And, as Brian has mentioned, any videos or pics I've ever seen of the claying process showed the smith claying a cool blade, heating it once the clay has dried, and then quenching it.

kdlarman
21st February 2006, 02:10
Hamon: descriptive term. Used to refer to the pattern formed by the hardened edge. Choji would be a clove bud pattern. Suguha is a flat pattern. The hamon is not a "thing" per se but is descriptive of the shape formed by the hardened area of the sword.

Yakiba: Hardened stuff. Martensitic steel. The shape fo the yakiba determines the hamon (as an example).

Ji: Usually refers to the pearlitic steel (soft steel area) of the blade between the yakiba and the shinogi.

Habuchi: Transitional zone between pearlite body (ji) and martensitic edge. The habuchi can be purely nioi (which is a very fine structure and looks like the milky way in a properly polished sword) and would be called nioi-deki. Or it can be nie (which is a coarser, larger crystaline structure in which each particle is individually discernable) and is called Nie-deki. Some swords have both structures together -- they are skill called Nie-deki usually.

Tempering: Tempering is usually misused as a term. "Tempering" means to heat the blade after clay application and quenching to reduce internal stresses in the steel caused by the quench and forging. The blade is heated enough to relieve some of the stress but not enough to cause the martensite to convert back to pearlite.

Yaki-ire: Process of quenching the blade.

Tsuchioki: Process of applying clay to the blade "blank". The blade is cool and very clean when this is done. FWIW Yoshindo Yoshihara demonstrated this aspect of the craft at the Tampa Token Kai about 2 weeks ago.

Now with all that out of the way... Hamon can be very distinctive of particular smiths and some smiths will do the same hamon over and over. To the inexperienced eye they often look very similar. Some smiths historically varied their style tremendously depending on time period, style, etc. That two blades look very similar means very little or very different means very little.

It is usually very easy with even the slightest bit of experience to pick out a "cosmetic" hamon. Look down a blade into a light source and the habuchi (the transitional zone) should light up. You can even see it in a poorly polished blade unless it has been buffed to the point of obscuring everything. If you are somewhat experienced it is pretty easy to tell a cosmetic applied hamon from the real deal.

Some also get confused by so-called hadori or kesho finishes. This style is very popular for many styles of blades and involves a final "highlighting" and "outlining" of the hamon. In more exuberent blades the hamon will have very "busy" areas grouped together to create a better "flow" to the look. This highlighting is *not* the hamon, just a highlighting. The hamon is the hamon is the hamon and represents actual structures in the steel.

Acid etched does not equal cosmetic hamon. A cosmetic hamon can be applied by masking a blade and selectively etching to make it appear as though it has a hamon. But if you look down the blade into the light you can easily see that there is nothing there underneath it to support it. Acid can also be used to make a hamon more visible as acids attack martensitic and pearlitic structures differently. Yoshindo Yoshihara and the Kapp's are coming out with a new book on polishing in the next month which even includes a short description on the use of acids to help bring up "sleepy" hamon. It is a shortcut and is often inappropriate for quality antiques. But the bottom line is that acid etched does not equate to being a cosmetic hamon. It could be or it might be a perfectly valid method for bringing up structures already there.

I have long suspected that some makers are using a stencil to "spray" a clay-like material on blades for quenching to save time. I was inspecting some potential blades for Bugei Trading that a Chinese company had brought by. I noticed the same "geometric" similarities between the blades and asked the company owner flat out if they used a stencil. He looked surprised and said yes. You could literally put blades on top of each other and the hamons were very close to each other. We rejected them because the blades had issues in shaping and metallurgy and the mounts were generally terrible. Not good user blades. Within months they started appearing at 3 different vendors billed as products from different "forges" in China. All using the same fittings and blades. Amazing bit of coincidence that they all use the same blade shapes, steel, hamon style, fittings, crappy ito, ... But I digress.

It a common misconception is that hamon follow the clay exactly. On some modern steels heat treated in an industrial fashion that is somewhat true (which is why some of those chinese blades look so similar across so many vendors). The steels are very simple and the hamon application very consistent. Also, many look like oil-quenched blades due to the lack of any other hataraki (workings) in the steel. Frankly this is good process for ensuring reduced failure during yaki-ire and controlling induced curvature (sori).

Anyway, on most steels and especially with folded steels if the temperature is correct the hamon will often track the clay somewhat but will also do different things depending on the grain of the steel if it was folded but also do different things due to varying thicknesses in the steel being quenched. Remember the clay is about controlling heat extraction to "freeze" the edge into a martensitic state. Cross sectional thickness also affects the rate a heat extraction. As does quench temp, quench medium, etc.

Hanwei appears to have a great deal more variety which suggests they don't use a template for their higher end pieces (the practicals looks pretty generic though). They also tend to have other activity appear in their higher end blades occasionally which points to water quenching.

Now if you consider hamon from one side to the other they can vary somewhat. As you get closer to the edge they will vary less (due to thinner cross section almost certainly being guaranteed of being totally hard all the way through). As you move up from the edge the hamon on each side can "do its own thing" to some extent although they do tend to track each other to some extent. If you must use a mental image, think that each side is "pulling" on the other side. The quench removes heat from the steel and lower clay on one side will insulate the one side more but the other side will feel the effect as well. So the hamon can ride higher on the one side but the side with more clay lower will "pull" it down somewhat. Frankly what makes many hamon interesting is realizing that it isn't just the clay that forms it but the clay on each side, the cross section, the steel alloys, the stuff in the folds, the style of folding, and how all those things push and pull on each other as the steel structures are locked in place.

Honestly I think many of the Chinese shinken from various vendors are being made with an identical industrial process. Or maybe even are all being made by the same people (who are giggling into their darjeeling about how us westerners argue over who makes better swords). Hanwei's stuff is rather distinctive and is obviously Hanwei (Paul Chen). Most of the other share a lot of properties with each other in blade shape, geometry, composition, look, hamon, mounts, etc.

Enough for one day for me... And I'm not even sure if I answered the original questions...

Blackwood
21st February 2006, 02:28
Thank you, Keith! Very informative. I must admit to having greatly let such terms as Martensitic and pearlitic steel wash out of my memory after my metalurgic class in college. I actually did a paper on the properties of the Damscene steel blades of the Middle East. There was a time when I could identify varieties of steel from microscopic cross sections! Sigh.

Brian Owens
21st February 2006, 04:03
...Since the tempering process requires heat-soaking the blade to a red-hot temperature...

...Tempering: Tempering is usually misused as a term. "Tempering" means to heat the blade after clay application and quenching to reduce internal stresses in the steel caused by the quench and forging. The blade is heated enough to relieve some of the stress but not enough to cause the martensite to convert back to pearlite....
Thanks for that. You're absolutely correct about my sloppy use of the term, which I have used to refer to what should properly be called "hardening." Similarly, hamon and yakiba are often translated as "temper line," which is equally incorrect.

Also, I learned a new term today, tsuchioki.

I will stive to be more precise in my use of jargon. Thank you.

kdlarman
21st February 2006, 04:17
Hey, Brian, no critique was intended. The term gets used a lot and some know what they're talking about even when it is technically incorrect. I just wanted to give a more comprehensive approach to the topic since all sorts of issues tend to swirl around questions of Japanese style swords and their construction. Its all good.

kdlarman
21st February 2006, 04:34
Thank you, Keith! Very informative. I must admit to having greatly let such terms as Martensitic and pearlitic steel wash out of my memory after my metalurgic class in college. I actually did a paper on the properties of the Damscene steel blades of the Middle East. There was a time when I could identify varieties of steel from microscopic cross sections! Sigh.

Cool. I have a box of old nakago from nihonto that were broken or irreparably damaged. My plan one of these days is to properly cut and polish the faces of these things and do a more rigorous analysis of construction methods. I have a photo around here somewhere of one I did as a test run.

kdlarman
21st February 2006, 04:37
Forgot to add one thing. The photo of the cross section rather vividly shows a blade with the hamon varying in location from side to side. The fine, smooth stuff is martensite, the grainier stuff is the pearlite and core steel. The blade was heated up too much during yaki-ire and the pearlite grain growth was excessive which made the blade brittle. Nonetheless, the variation from side to side should be obvious. And it shows how the formation is dependant on a lot of variables -- it ain't just straight through.

Brian Owens
21st February 2006, 05:15
...I just wanted to give a more comprehensive approach to the topic since all sorts of issues tend to swirl around questions of Japanese style swords and their construction. ...
It's really great having someone post here who knows what he is talking about from actual experience.

Those of us who only swing a sword from time to time can repeat what we've been told, but it's not the same.

I've never been to a forge, although I have observed a renowned token at work polishing, so having a report from someone with "first hand" experience is a blessing.

I wish I could have been to the Token Kai. I have one book by Yoshihara, Kapp, and Kapp, and am looking forward to the next. I was in Tampa in December, but couldn't have made it this month even if I had known about it. (I assume this is a "members only" gathering of some kind?)

kdlarman
21st February 2006, 17:51
You could pay a small admission price at the door at the Token Kai around the country. No big deal. One good thing is that the American Branch of the NBTHK is starting to gear up more and more. They had a kantei in one room this year with 5 blades to study in hand and try to identify. Early Fukuoka Ichimonji, Ko-Bizen Tomasa, Nakajima Rai, Chikuzen Sa Sadayoshi, and a wonderful Ko-Mihara blade. Even better was after they announced who made what, Andy Quirt put down a Rai Kunimitsu daito next to the Nakajima Rai blade so you could see the differences a few generations made. That was invaluable to me since I'd kantei's the Nakajima Rai as Rai Kunimitsu. Made the differences vivid in my head. They also had a wonderful lecture on Akasaka Tsuba by Jim Gilbert along with, what 20-30 very high end tsuba to handle and study.

On the Token Kai floor there were enough very high end blades to make even the most experienced guys hit overload very quickly.

Yoshindo was there along with his lovely wife. They had a copy of their upcoming book on polishing on the table and I'm sure there are a few sections in there that are going to cause some serious debate. Also no shortage of concern about "do-it-yourself" work will arise from this one.

kdlarman
21st February 2006, 17:56
And by the way, at the West Coast Tai Kai I helped my friend Ted Tenold put on a display and discussion of antique blades. Since we both straddle the two worlds we're trying to get more martial artists educated on the other aspect of their world as well as help the collectors better understand the martial artists. We put out some really interesting blades and I brought by the Heian inspired Tachi by Ono Yoshimitsu we have up on our http://moderntosho.com site for people to see in person. Mike Yamasaki of the NBTHK-AB came by as well to offer up some additional comments. We're hoping to repeat it next year and maybe bring in some even nicer blades. We didn't mention it at the meeting but we have about 6 blades on the table. The value of those blades was probably close to $100,000. But we didn't mention it because we wanted them to pick them up, study them, and learn something without being intimidated by the price tags.

We are very lucky in this day and age. We have everything from simple tools for training ranging up into the very best of the antique world. Personally I'm glad to see more and more martial artists learning more about the history, craft and subtlety of the very weapon they train so hard to learn to use. I think it can only improve us all to learn more about as much as we can.

That said, gotta go out and finish rubbing out a new saya for a customer...