Talk:Japanese swordsmithing

message: The intro is a bit over-broad.  That material is mostly covered in Katana, like the discussion of daisho fittings; it should be a bit more focused on the contruction article that follows.  Just an area that needs a little work.  jesup 14:01, 29 November 2006 (UTC)
replies: text: You can easily find out by clicking on the link provided, but a daisho is a pair of swords, one large and one small. The long sword, or katana, was used for outdoor combat, while the short sword, or wakizashi, was used while fighting indoors, or in close quarters. And, while I think the article could use a little improvement, I think it is very useful to those of us who actually use and construct these fantastic weapons, and also for those who are merely interested. Zaereth (talk) 17:56, 4 November 2008 (UTC)
thread_title:  Introduction 

message: I greatly rewrote the section on repros; it should probably be moved to lower in the page, and could use a little more work.  jesup 15:02, 29 November 2006 (UTC)
thread_title:  Rework, repros 

message: I've written a major revision of the polishing section, using summarized information gleaned from my latest purchase. I was wondering how it could be improved further before being formally appended into the main article, if or when it becomes good enough to be added. CABAL 17:55, 16 December 2006 (UTC)
replies: text: I'm going to insert the content soon. If there are no violent objections, I'll take that as a yes. CABAL 11:36, 21 December 2006 (UTC)
thread_title:  Polishing section expansion 

message: I think it should be noted that one of the main purposes for folding the steel, other than purification, is to provide alternating layers of steel with different hardenability. Typically, a block of extremely high carbon steel is welded to a block of medium carbon steel, then folded from there. The number and method of folding determines the grain direction and courseness. Typically, 10 to 14 folds are used, (number and method depending on what part of the blade the steel will be used). After 16, (65,536 individual layers), the act of folding no longer gives any benefit to the steel. The alternating layers back each other up, which combines hardness with ductility to create toughness. A good book on the subject is called "A History of Metallography", by Cyril Smith. Or check out this detailed website: http://www.samuraisword.com/REFERENCE/making/japanse_swordmaking_process.htmZaereth (talk) 22:18, 2 October 2008 (UTC)
thread_title:  Construction - Folded Steel 

message: It might be helpful to note in this section, especially for those of us who actually own a shin ken, (real sword), that one should never polish the tang. Doing so will extremely devalue the sword.Zaereth (talk) 23:16, 2 October 2008 (UTC)
thread_title:  Polishing 

message: The following lines in the "Construction" section are not entirely accurate. "If steel cools quickly, from a hot temperature, it becomes martensite, which is very hard but brittle. Slower, from a lower temperature, and it becomes pearlite, which bends easily and does not hold an edge."
To harden steel, it must be heated above the austenite transformation temperature, (1400 to 1500 degrees F). At this temp, austenite crystals form, and grow larger as temperature increases. (Smaller crystals make stronger metal, so the steel is not usually heated much beyond the A1 temp, although katanas were often heated to as much as 1600oF. Also, before quenching the steel also needs to be annealed, or better yet, spheroidized, to ensure crystal growth from the smallest possible size.) Controlling crystal size helps to increase the shear and tensile strength of the metal.
The hardness of the steel is solely a function of cooling time. The faster the metal is cooled from the A1 temp, the harder it becomes. Crystal size, on the other hand, is largely unaffected by cooling rate and will be the same in the edge or the back. According to A History of Metallography, and a PBS special referenced in the article, the thickness of the clay coating on the edge and the back, and even the temperature of the quenching water, were often carefully guarded secrets, fine tuned by the various schools to produce the correct hardness without any further need of tempering!
I am removing the temperature info from the sentences so as not to confuse the issue. The new sentences will read: "If steel cools quickly it becomes martensite, which is very hard but brittle. Slower and it becomes pearlite, which bends easily and does not hold an edge."
If there are any questions or comments please leave them here. Zaereth (talk) 00:29, 1 September 2009 (UTC)
thread_title:  Heat treating, temp vs. time 

message: I found this diagram on the French wikipedia. It looks to me to be far mor accurate at depicting the different methods of assembling the different steels during the final forging. I think we should replace the one we have with this one. Does anyone agree/disagree? Zaereth (talk) 21:23, 25 September 2009 (UTC)
replies: text: Works for me. Kirill [talk] [pf] 00:48, 26 September 2009 (UTC)
replies: text: Great, then I'll make the change, although I will need to alter some of the japanese words in the text to match. It might be worth noting, as stated in A History of Metallography that there are almost an infinite number of ways that the steel can be assembled, such as drawing the steel out, folding the kawagane into a 'U' shaped trough, and inserting the shingane, (as depicted in the PBS special). Or, the steels could be assmebled in their right locations as a steel block, and then drawn out into the sword shape so that the correct steel ends up in the right place, as depicted here. Give me a couple more days to go over my sources and I'll work out some appropriate changes. Zaereth (talk) 16:28, 28 September 2009 (UTC)
thread_title:  Assembly forging diagram 

message: The information added today, to an entirely unsourced section, is also completely unsourced: "The pupose rather, for the grooves, is in the instance of stabbing an opponent the blade could get stuck due to the fact that the inside of the torso is like a vacuum, so the grooves allow air to flow freely into the torso eliminating the vacuum effect making easier to pull the blade of of the opponent."
I have never heard of such a thing, as it sounds more like urban legend. The small surface area, shape of the sword, and physical structure of the body seem to negate this, (a body is under pressure, not vacuum). It also directly contradicts the sentence just prior: "It leads to no demonstrable difference in ease withdrawing a blade nor reduce the sucking sound that many people believe was the reason for including such a feature in commando knives in World War II."
I'll see if I can find sources for this information, but I believe the only purpose for the grooves, as far as I've read, is that they lower the weight which allows for faster movement. This is also expressed in the sentence: "The grooves are analogous in structure to an I beam, lessening the weight of the sword yet keeping structural integrity and strength."
If anyone has any sources to confirm any of this info, it would be appreciated. Zaereth (talk) 22:01, 26 October 2009 (UTC)
replies: text: I'm never surprised by the crap some of these whackjobs try to put in these articles either because they're bored or just morons!  Thanks for fixing it!--Mike - Μολὼν λαβέ 05:02, 10 December 2009 (UTC)
replies: text: Yes, thanks for that. I have added the reference you provided to the article. Zaereth (talk) 20:06, 10 December 2009 (UTC)
thread_title:  New information unsourced, and a strange contradiction 

message: Murray Carter is an excellent bladesmith, but he makes knives, not swords.  He is not a licensed swordsmith, nor does the article cited assert this.  Yoshimoto is the family lineage of knife smiths of which he is the successor.  This is not the same as being a licensed swordsmith by the Japanese government.  — Preceding unsigned comment added by 126.209.98.76 (talk) 05:44, 7 April 2013 (UTC)
thread_title:  Error in modern swordsmithing section 

message: Right now the article has 
"The high carbon steel, called tamahagane, and the remelted pig iron, called nabe-gane, are combined..." 
Followed later by
"The nabe-gane is heated, quenched in water, and then broken into small pieces to help free it from slag. The tamahagane is then forged into a single plate, and the pieces of nabe-gane are piled on top..."
I found this hard to follow. I think that this would be better:
"The pig iron is heated, quenched in water, and then broken into small pieces to help free it from slag. The high carbon steel is then forged into a single plate, and the pieces of pig iron are piled on top..."
This avoids having to go back to a previous paragraph to find out what the Japanese words mean. --Guy Macon (talk) 18:44, 22 October 2015 (UTC)
replies: text: Sounds good to me. With the exception of a few words, like "hamon" (which is widely known and not as misleading as "temper line), or "nioi" and "yakiba" (which have no English counterpart), I'm all in favor of using English terms whenever possible. Why say "tsuba" when "guard" works more effectively, or "saya" when "sheath" will do just fine? I have no time to work on it right now, but may in the future, unless you want to do it first. Zaereth (talk) 00:31, 29 October 2015 (UTC)
replies: text: Sorry for the delay, but I finally had a chance to get back to this. I changed most of the metal terminology to English, but have only done those sections I've helped with. I'll have to get back to some of the other sections later. Zaereth (talk) 22:02, 27 March 2016 (UTC)
thread_title:  (From the Wizard of Oz) Hocho-tetsu, Tamahagane, and Nabe-gane, oh my!  

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message: At what point does the blade get its cutting edge and how is it sharpened? Is this part of the 'polishing'? Absolutely no mention is made of this either in this article or the one on polishing which is odd given that the whole purpose of a sword is to support a cutting edge.
212.159.76.165 (talk) 15:15, 2 December 2019 (UTC)
replies: text: The sword is heat treated without an edge. The reason being that, when quenching in water, carbon is rapidly removed (blasted) from the surface of the steel during the quenching process. Traditionally, after quenching and "tempering" the smith would give the blade a rough edge with a draw knife to create the bevel, and then send the blade to a polisher for sharpening and polishing. (I put the word "tempering" in quotes because there's little evidence that tempering was actually used on ancient swords. Usually, the quench was done with just the right amount of insulation to ensure the blade would reach the proper hardness upon quenching without the need for tempering, but that takes a lot of practice and trial-and-error to perfect. Modern swords are usually tempered after quenching.) In the modern age, the smith will often use a belt sander instead of a draw knife to apply the bevel before sending it to the polisher. This is described in the differential heat treatment article, but perhaps a short description should be added here as well. Zaereth (talk) 17:19, 2 December 2019 (UTC)

text: I might add that, Japanese swords do not really have a lot of impact resistance in the way European blades do. They actually bend and chip quite easily, but they're deigned for completely different styles of fighting. In the Japanese style blade-to-blade contact is avoided as much as possible but rather the swordsman goes directly for the kill, in stark contrast to the sword-and-buckler style of Europeans. This promoted the development of an edge with a high degree of sharpness and hardness, allowing the sword to hold that edge for long periods of time if properly used and maintained. The superior cutting ability comes from the shape of the edge. If you examine most swords, razors, and knives you'll notice there are two angles; one for the bevel and a slightly shallower but much narrower angle for the edge itself. In the Japanese sword, there is only one angle; the bevel and the edge are sharpened and polished as one. This steeper angle give a superior cutting ability while the excessive hardness allows it to hold that edge for a long time, even after cutting through bone and flesh, or bamboo. (I have one I use when I go out for firewood or need to cut down small  cottonwood trees in my yard. When it comes to removing limbs there's no better tool; I can de-limb a 30 foot spruce in under a minute, about 5 times faster than with a chainsaw. And I've only had to resharpen it once after 10 years ... mostly from missing my mark and hitting rocks and dirt.) This also means sharpening and polishing are one, and the entire process can take longer than the forging did, which is why it's usually done by a specialist. Zaereth (talk) 23:22, 2 December 2019 (UTC)
replies: text: Thank you that's very informative. You're right it is in the differential heat treatment article (which I hadn't read) but I think it would be a useful addition to this article too. 212.159.76.165 (talk) 17:05, 3 December 2019 (UTC)
replies: text:  Done. (Come to think of it, I only had to sharpen that sword because I cut down a 4 inch thick cottonwood tree that happened to be right next to a metal sign post. Aiming for the ground between them, I sliced down at a steep angle, trying to use just enough force to cut down the tree, but it went through the soft wood like a hot knife through butter and sunk about 1/4 inch into that steel post. Chipped the hell out of the edge and warped the blade, but I was able to bend it back into shape and put on a new edge for another decade of heavy use.) Zaereth (talk) 19:24, 4 December 2019 (UTC)
thread_title:  Cutting edge