OceanoNox

Thank you for your hard work and for the link!

I will caveat that by saying that some iaito have very poor balance. Case in point, my shinken is about the same weight as my iaito, but it feels much lighter than the iaito. There are some iaito made especially light and thin to avoid injuries in beginners or people with less muscular strength.

I am 1m88 tall. My sensei had seen a few nice blades and had them sent to the dojo for us to try (another dojo member was also looking for a shinken). That blade simply fit me.

In iaido, shinken is recommended eventually. It may implicit, but for 5th dan onward, shinken is practically mandatory for testing and taikai. If you go to a dojo with high ranking practitioners, there are no mogito, only shinken being swung around. 900g is fine for a iai shinken. If it has a bohi, like most swords for iaido to avoid tennis elbow and such repetitive joint injury, it is not recommended for cutting, especially if you are a beginner, since it is a bit easier to bend. Weight distribution rather than total weight is more important for iai, but you need to swing the sword (single-handed) to check if the sword fits you. The sori and kissaki shape are also very important (I know a person with a sori almost like a tachi, but he is an exception). N.B.: For comparison, my own shinken for iai (I do ZNKR iai and muso shinden ryu) is 79.6 cm long (sori is 2.0 cm) and about 970g. The blade tapers towards the tip, and it feels like a feather compared to my mogito.

Do you remember where you read/heard that? It's very interesting to me. In my comment above, Isawa talks about failure (and I think there is another who talks either about mekugi failure or failure at the habaki). My student did a calculation, and the kachushi tsuba with a thick mimi "keeps" the shockwave bouncing around in the tsuba, for instance. I wonder who much it is mitigated with everything else. PS: It might be Yaso who published a paper about impacting a Japanese sword. They identified the nodes: at the monouchi and at the mekugi, i.e. where the vibrations are smallest. When doing it on a naked blade, there was some vibration at the nodes, but with a full koshirae, the vibration was basically 0 at these nodes.

People don't aim typically for the sword either, but if you block and control your opponent's weapon, a guard of some sort helps with that purpose. With how it's wielded, a tsuba also makes a lot of sense on a nagamaki than a naginata. @O koumori here are some info I got from earlier sources about tsuba: "鍔は只拳の楯と聞物を太くも太くもなきは非がごと" in a Hayashizaki shin muso ryu scroll dated from 1601 (if memory serves). This one calls a tsuba a "shield for the fist(s). Tsukahara Bokuden wrote: 鍔はたたふときにしくはなきものを細きを好む人そ拙き 皆人のしらてや恥をかきぬらん鍔のつめある習ありとは 鍔はたた切ぬき有を好むへし厚き無紋を深く嫌へり あら鍔はいかに厚くと切れぬへしたとへ薄きも古き好めり It does not directly refer to tsuba as hand protection, but states what should be preferred in terms of design. In 1719, someone called Isawa (井澤蟠龍子, in 武士道叢書) wrote: "鍔は無地の厚きを用へし 大サ三寸四五分短刀（わきざし）の鍔三寸ほどにすべし 見るところのよろしからんを思ひてすかしあるうすき鍔を用べからず打合とき切破ことあり" which states a preferred design for a tsuba to resist blows (along with the sword itself). I couldn't get the direct citation, but it's cited by both Nagaoka (1942) and Sasano (1975): in the essay 鈴林類纂 (Edo period), tsuba are recommended to be essentially like kachushi tsuba (thicker mimi than seppadai, have some, but not too big, sukashi). The shape would prevent damage to the mekugi when hit, and the small sukashi would prevent blades from going in them or catching them. Now, the issue is why all those are not in accordance with one another about design. At any rate, the first is clear, the others are less direct but imply that tsuba are hand protection. The funny thing to me, is that all the works that say tsuba are for slip prevention (like in the Art of the Samurai: Japanese Arms and Armors 1156-1868 catalogue of the MET), I have not seen any period source being cited.

Unfortunately, I have even seen the MET catalogue on samurai, written by the Tokyo National Museum curators, specifically say it, adding that it was not for protection from blows. Sasano as well talked about the tsuba being to prevent slipping, because thrusts are the best attacks against someone in armour. Nevermind that we have tsuba on tachi, whose curvature makes the idea of a thrust dubious. Just like @Jacques wrote, koryu teach to use the tsuba to protect your hand or catch an enemy's weapon. Shinkage ryu does too. It is clear from koryu documents that tsuba were thought as a protection from blows for the hand.

Some of the results come from a study made by Nippon Steel (新日本製鐵第一研究所) using CMA (Computer-aided Micro Analyzer or Comprehensive Multi Analyzer). It seems to be like EPMA but faster and with a larger analysis area. Unfortunately, the paper does not give the details of the research report...

I have to admit I haven't read much outside of academic work on Japanese swords. I am trying to remedy that by reading stuff written by Alan Williams, and get to other stuff, the goal being to understand the similarities and differences in methods and goals when making swords (I am still not sure why the Japanese apparently aimed for such high hardness). That being said, so far, the body of academic work on Japanese swords, in particular material science and mechanical properties, is quite consistent, whether it's about old swords or modern ones.

I cannot say whether it's useless or not, but the paper, and others that deal with Western swords made in the same way, shows a banded structure in the cross section. I think the idea is less to have a uniform carbon content and more to have a composite structure "throughout". There are also swords that seem to be made of one type of steel. To be honest, my feeling is that the author worked from the conclusion backwards to find fitting evidence, instead of gathering evidence to come to a conclusion. I don't think they misrepresented the sources they cited, but I was left wondering how representative their examples were.

The title seems like clickbait, here is the original title and reference info: 日本刀の素材は本当に玉鋼か？刀剣類の分析から素材鉄の変遷を考える, 大村 紀征, 金属 Vol.94 (2024) No.7 The conclusion of the paper is that tamahagane was mainly used for Japanese swords merely during the Bakumatsu (specifically the last 70 years of the Tokugawa Bakufu). Arguments are: 1. Little local production of steel, that did not match consumption and demand; 2. Large imports (either official or contraband) of iron and steel from the Chinese mainland and the Korean peninsula, with added metal from Europe later; 3. Steel from the Chinese mainland contains more copper than the iron sands in Japan, and several extant swords that were analyzed show a copper content congruent with Chinese steel. 4. The whole "hard steel for edge and outside, soft steel for the back and inside" construction of nihonto is relatively new, and older swords (in particular koto) were made with mixing soft and hard steel, folding/twisting them together and forging the sword from the block (same as several swords found in Europe too). 5. Analysis of some iron/steel items imply they were made by mixing non-Japanese pig iron and native iron sands. Personal impression: The author does not appear to mention export of swords from Japan to China, nor the pervasiveness of recycling and oroshi. He doesn't cite other studies that show virtually no copper in Japanese swords from Kamakura to Edo (Prof. Kitada, 日本刀の材料科学), i.e. the use of native iron ores to make Japanese swords. I am yet to understand how they obtained (maybe from another study?) the numbers for production and demand of iron/steel items during the history of Japan. The paper itself is certainly trying to shake the established idea, relatively new according to the author, that nihonto = tamahagane, but as of yet, I lack the time to review the sources and studies cited in the paper, and the knowledge to agree/disagree outright.

My apologies for the thread necromancy, but I stumbled upon this article: https://www.research...Edo_period_1603-1868 The sources cited appear reliable (at least the ones I know). If the estimations are correct, some iron tsuba would be a few tens of euros.

Leaves with dew drops maybe? And this is why I think nunome is not so good for the long term, all the precious metal ends up somewhere else than the tsuba.

This is one of the only example that seems like a credible sword scar on tosogu: http://www.ksky.ne.j...9/katanainfight.html Also: http://www.ksky.ne.j.../tsubaradiation.html Here is another discussion on the topic, if you haven't seen it before:

A colleague of mine also has the 廣 kanji in his name. In that case, it's not related to old or new, that's just the way of writing it, and he said he accepted the use of 広 because the old kanji is not always known. As far as I know, on official papers, it should be 廣. I cannot comment on why the NBTHK used the new kanji instead of the new, especially if the mei uses the old kanji.