OceanoNox

I agree with you. Trying to rust reliably my own tsuba, there are a dozen recipes to promote uniform rusting on iron. The ingredients and compositions of the recipes differ significantly, and thus the iron oxide varies too, in aspect, thickness, and colour. Since heat is also involved to accelerate the oxidization, it gets really difficult to investigate. Some time ago, I joked about using carbon 14. Radiocarbon seems to give plausible results for the dating of rust, although it requires sampling of metal (https://www.tms.org/.../0305/Cook-0305.html).

You know, this is one of the areas where AI could be useful. I know a company that has a learning AI that can now identify the types of fracture when fed microscope photos of failed metal pieces. It's also in the vein of big data: scan as much as possible and use scanning models to see trends appear: what texture is preferred, are there specific designs that appear, size, etc. An issue in this is the dating. I did not know about the school names being set later than the production era for sukashi in general, but for tosho and kachushi, Mr. Ogasawara and Mr. Katsuya did write that while attractive, the names meant nothing and there was not one shred of evidence that the tsuba were made indeed by swordsmiths or armourers (although Prof. Michel-Tanaka did tell me that his swordsmith acquaintance was making tsuba essentially in the tosho style; but I have no idea if this is a transmitted thing or if he made it to fit the category).

Yes, I found the citation in a paper by Mr. Kawami about the analysis of iron tsuba: http://www.kurokawa-...1904281025162413.pdf The paper itself is referring to a translation of Valignano's travel journal: https://www.heibonsh...jp/book/b161281.html I assumed both the translation and the citation were correct. Unfortunately, I cannot find the journal itself, nor have I read any of the existing translations.

I have cited this previously, but it's just before Edo period: Alessandro Valignano wrote that lord Otomo Sourin bought an iron tsuba for the equivalent of 4500 ducats. Swords would be bought for the equivalent of 3000~6000 ducats. Some conversions give the value of a 16th century ducat to about 148 USD. So the price of the tsuba was about 666,000 USD and the price of swords was in the range of 444,000~888,000 USD

I think it started with Oda Nobunaga who wanted to assert his power: He ordered sword hunts to both enforce class distinction and decrease the likelihood of rebellion. Indeed, this should mean that anyone who could get a weapon was allowed to own and carry it. In the book War and Tsuba by Nagaoka, he mentions that although there were rules about koshirae, many did not obey, and although there were complaints, he says that the rule was not enforced. It's also known that Kage Ryu uses the so-called "chouken" (長剣), which is like a nodachi. They decided to practice in secret because of the length standardization in Edo period (they can wear it and draw from the belt).

There is a manga called "Samurai executioner" (Kubikiri Asa) that is based on this family. It was apparently based on legal documents from Edo period. Thank you for the link!

It has been said already, but in iai, one only cuts air (and occasionally, oneself). To your points, using a shinken is an expectation in the long term. What is taught is that one starts with a bokuto, then moves on quite quickly to a non-sharpened blade, and above a certain level, a shinken is recommended by the sensei (and it can become mandatory for gradings or competitions). But typically, the sensei is telling the student what they ought to use, with all the points I raised before (the blade needs to fit the requirements of iai practice and size). Knowing one's own sword well is necessary, but I remind you that practicing with only one sword is because it is relatively difficult for many to buy more than one sword. Famous Nakayama Hakudo did have several swords that he used in rotation. More to the point of iai, the sword is a tool, and anything can be used to replace it if necessary (I was told to use a wooden spoon or even a towel, or simply nothing).

This will go against the grain, but here is what I have seen in Japan: Some will use old blades (Nosyudo, the iaito maker, used to sell some, likely for that purpose, but they were not museum or collection level blades), but old iron tsuba are more common. Nowadays, uchiko is only recommended for heavy oxidation, which can occur during a humid summer; otherwise, alcohol with a fine weave cloth and oil is what many do. For what it's worth, after almost ten years praticing with a shinken, the damage is: scratches on the kissaki, a millimeter broken off the kissaki from hitting the floor (doing the kata tora no issoku), and oxidation on the mune, especially near the habaki (from touching and exhaling during cutting). The main points against using an antique blade are: 1. The shape may not be quite conducive to iaido practice, i.e. the sori and kissaki shape may not be quite adapted to nukitsuke; 2. The blade's history being unknown (smith sometimes also unknown), it is unclear if the blade is safe to practice with. There may be defects and some prior deformation that make it somewhat "fragile". (3. The blade is too short for your height, and thus does not allow for "proper" technique to be practiced.)

This is very nice! I cannot believe it's only your fourth attempt. Congratulations on a beautiful tsuba.

I have found this: http://www.harimaya....ai/pack2/tigiri.html It seems to have been used by Niki (or Futaki) family during the Ashikaga period, and in Edo by many others (松平、千村、岩波、小城; maybe Matsuhira, Chimura, Iwanami, and Oshiro/Ogi).

丸に千切 (maru ni chigiri) https://myoji-kamon.net/kamonDetail.htm?kamonName=丸に千切り

I considered it, and probably would have if I weren't married (my wife is very much into newly build stuff). The main issue, as far as I am aware, is water pipes (and termites, but one should be able to inspect that fairly easily). The reduced price may mean nothing if one needs to hire an excavator to dig and replace the water lines. Another thing that is done, is to demolish an old house without destroying the wooden beams, and reuse them to make a new house. You get the aged looks but with a more sound structure.

For what it's worth, Nobuo Ogasawara wrote in the booklet "tsuba" that it should be observed mounted on a sword, since it's its primary purpose. I know there is a tsuba with a moon and the kashira has a bat on it: they are supposed to be mounted, so the bat looks like it's passing in front of the moon. In general, Mr. Ogawasara thinks one should look at tsuba as if the nakago ana was filled. On a personal note, I can appreciate the artistry of kinko work (there is a kashira somewhere that has a castle inlaid, with a bridge leading to it, pure insanity), but I really enjoy the simplicity of tosho and kachushi tsuba. More recently, I have gained a new appreciation of the Onin and Heianjo tsuba. In the end, I go for the nice textures in iron (at least I would, if I could spare the money). If anything, many kinko tsuba are, to me, a bit too much.

From top right to bottom left: Mr. Iwasawa. Aizu Shoami school. Related to Ryōi.There are sukidashi takabori iron tsuba with the name (mei) Iwazawa Ryōchin. Lived in Mutsu (kuni) Iwashiro. Late Edo. The kanji: 岩沢氏。会津正阿弥派。了意の一族。岩沢了陳と銘して鋤出高彫の鉄鐔がある。陸奥国岩代住。江戸後期。

Nice one! Funny to see I used the same source for images. @Rivkin, I agree with you, and even would add that we are limited by survivor bias. There is little to say that the blades we have are even representative examples for each era. This is even further limited by the impossibility of conducting destructive analysis in many cases. From some recent articles, the use of X-ray diffraction or neutron diffraction gives good information but is clearly limited. A nice section cut and polished to see the microstructure, get the hardness, chemical composition (melting etc.). To me, Prof. Kitada does manage to have al: knowledge of old steel, modern steel, and history (although maybe more as an amateur than dedicated scholar). Control of the grain size is indeed important, first uniformity, and then small grains, those give the best mechanical properties. For Mn, P, and S, it's also why we add Mn to steel even if we don't need it for the final properties of the steel, it's essentially there to capture the sulphur into MnS inclusions. These are actually not detrimental per se, unless they are exceptionally large, at which point they may become the initiation points of cracks. I want to ask you about the long heating of European swords. This sounds like aging, but in carbon steel, that would spheroidize the steel (form large spherical carbides). Unless it's simply some low-temperature tempering, that might indeed recover some martensite, and at least reduce the internal stresses (to be clear, it was done in Japan too, but for some reason, this is almost never described in documents for the layman). Do you have more info on the topic?

I an not sure what is meant precisely with "alloy steel" or "army sword steel", but the hagane and kawagane with high carbon in older nihonto are spring steels, essentially. The main reasons why Japanese swords bend less and when they do, they remain bent are: (1) Blade cross section: the blades are thick enough that they are resistant to bending. This resistance depends mostly on the Young modulus and the size of the cross section (i.e. it doesn't depend on the type of steel); (2) The use of low carbon steel (sometimes close to iron) for the core, that has such low yield stress that it will deform permanently when bent. The hagane and kawagane may not be permanently deformed but the core is, and the sword stays bent. I have had discussions with friends, and we can continue here, but in my view (and from what I have seen so far), there is little difference between the steels used for swords in Japan and Europe. The main differences seem to be the type of non-metallic inclusions, which form because of elements contained in the original iron ore and the walls of the bloomery furnace, and the hardness. Maybe the cleanliness too (sulphur and phosphorus contents), but I need to gather more data and reports. So far in my review of published data, the Japanese swords' edges appear quite harder than European swords in general (regardless of composition, even some crucible steel swords). I see it as a choice to aim for strong cutting edges, at the expense of impact resistance. I am not sure why this choice was made. Many will say that Japanese martial arts with swords teach to deflect and evade rather than block the enemy's blade, but my own school at least does very hard edge to edge blocks (and I was told to consider the sword a consumable, in a fight).

Yes. I know an experimental archaeologist in Japan working on the evolution of tatara, so I might ask him about that. He told me that Japan exported a lot of swords to China, and I think I read that China decreased the price per sword they were willing to pay, so the Japanese side increased the number of swords sent for the next shipment. It does seem weird that Japan would get Chinese material and send it back, since a lot of the iron technology came from China and Korea. I will reread Prof. Omura's paper with more focus.

To add about Prof. Omura's research paper, it is part of a larger research project, funded by JSPS (Japanese Society for the Promotion of Science, the main government agency for basic research funding, relatively competitive and attribution depends on both the application and the applicant's previous research results and achievements). The topic was "The iron that changed Asia " (アジアを変えた鉄). There was a symposium at Kyushu National Museum (https://www.kyuhaku..../event-220128-2.html), and Prof. Omura's own website gives more details (http://ohmura-study.net/410.html).

To add, also steel from the Netherlands (anywhere, really). I did not know that, but it seems the "nihonto = tamahagane" narrative started, according to Prof. Omura, after the sword ban of Meiji. He adds in the conclusion that nihonto were not made with tamahagane during the bakumatsu because it was good steel, but because it's what the smiths could get their hands on. So tamahagane was mainly used for 70 years out of 1000 years of history for nihonto. This is a tough paper to digest (a lot of content, and it challenges my own ideas on the topic), but very interesting.

Thank you Robert! Thank you for the comments too. I'll answer below, but I'll use your comments to upgrade the file. If I can get close to a "definite" version (HA!), I might upload it. I realized later I had forgotten to erase the duplicated Vickers hardness data. About the concentration of P and S, I have no idea where the sands/ore came from for the old swords (or rather if it was in Prof. Kitada's book, I skimmed over it...). About the folding part, it's the section I am not happy with; I wanted to get over it in one slide, and the nuance is difficult to get. I did want to explain that each type of steel was separately worked before being joined into the final block for the sword. And for the carbon content, I was amazed too. From what I understand, they usually look at the fractured areas when they break the initial metal before sorting into high or low carbon steel. It seems the folding tends to give a pretty consistent 0.5~0.6 mass% carbon, so maybe they realized that a certain number of folding cycles worked. I know that the people from older times were likely just as smart as us, but knowing how little technology they had, I am still amazed at what they did.

I thought it might be East 東, as seen here: http://codh.rois.ac....nsho/unicode/U+6771/ The writing style is Seal script, tenshotai 篆書体. The kanji for king 王 can look like this: http://codh.rois.ac....nsho/unicode/U+738B/

I used the data available. I'd like to keep updating this file, so if you have other sources, please let me know. EDIT: I wonder if the smiths themselves measure the temperature or keep doing it by eye and experience.

Thank you Brian!

Nihonto-Steel.pdf Hello all, I have been recently quite miffed at the apparent return of the "Japanese SteEL was Baaaad" cliche on the internet. I've yet to seen anyone back their claim and decided to gather some of the most excellent data that has been published throughout the years. A lot is in Japanese, which means it remains inaccessible to many. At any rate, feel free to take a look at it. I have focused on the metallurgy, i.e. the chemical composition, microstructure, and mechanical properties. Cheers

This page (http://www.kodokei.com/ot_043_1.html) implies that the so-called tokei tsuba was indeed popular, and the design was already not new in 1770. The page goes on to say that it also looks like a sun with its corona. There is no implication that it's a christian theme, simply a clock gear (specifically a Japanese clock gear). The document cited may be this one: https://kokusho.nijl...io/100238317/2?ln=ja, but it's more than 600 pages long of old Japanese... I have seen it written that the sun/sharp gear appearance is a hint to the Jesuit IHS symbol, but I cannot confirm (the symbol itself is certainly juuust old enough that the Jesuit mission in Japan could have introduced it: 1541 for the symbol, 1549 for the mission). To @Jesta, I feel the same way for many tsuba designs, especially the tosho and kachushi. There is a simplicity and rusticity that is extremely appealing to me, but I wonder what was the intent behind those designs. Is there a hidden meaning? Did they simply like the shape? Was it simple because they lacked the technology or know-how to make more elaborate depictions?