OceanoNox

Thank you folks, that's helpful. I had seen some seppa that had seemed to follow the bohi, but I did not know it was supposed to be like that. Most of what I had seen was probably mass produced.

Hello all I have been mulling over the possible designs of seppa. I know of the "scales" like design, and the crenelation like design, but I have been wondering if there are sources or collection showing the different types of seppa. Incidentally, I was also wondering if seppa were made to fit a specific koshirae, or if they were made in bulk and adjusted as necessary. So far, I haven't been able to find much about the topic, despite the fact that they are a very important part of the koshirae.

Magnificent, Jussi. Thank you very much for you hard work and for uploading the data.

Beautiful! Congratulations!

Dan, you are being dishonest here, and I am being polite. The very first photo in the "Silver ring in tsubas" (https://www.militaria.co.za/nmb/topic/52786-silver-ring-in-tsubas/#comment-551308) is taken at an angle, and there is nothing in the surface roughness indicating casting, rather it is a look one could easily obtain during forging. My opinion is corroborated with more than 10 years working in research in mechanical and metallurgical engineering, reading actual academic research on the topic of tsuba (as well as period documents, when possible), and trying my hand at the different DOCUMENTED techniques of tsuba making. And if you are looking through my commenting history, you would see the links or references I have posted (I am even the one who posted the research report for the archeological find of cast soft metal tsuba in Nara). If anything, I always try to give a reference to support my opinion. Do it then. Find one of these supposed antique cast iron tsuba, and have the tests made. Or send them to me to do it. I have access to X-ray, electronic microscope with chemical analysis, and micro-hardness (not quite non-invasive, but still considered relatively non-destructive, if you can bear a barely visible indent). Put your money where your mouth is and do the analysis, instead of telling others that they are close-minded and scared, then taking offense at being called out. I am doing it. I had an idea about tsuba research, and my students and I are doing the calculations and experiments to see it through. It's not cutting edge, it's probably not very noteworthy, but we are doing what's necessary to find out if we are right or not.

The original picture shows roughness, which is very easily attributed to rough forging, rather than casting. If anything, casting a liquid metal might leave a flatter surface, albeit with maybe a sand-like appearance. But, I may have mentioned this somewhere in the 20 pages here, and I am certainly not the only one: we cannot judge if a tsuba is cast iron from photos alone.

Dan, the first photo in the original topic about that tsuba shows that area is flat. Why would a non-flat area be indicative of casting?

I agree: In "Japanese aesthetics and culture: A reader" edited by Nancy G. Hume (recommended a long time ago on one forum by the late Ford Hallam), there are indeed clear quotes about the evolution of the wabi aesthetics praising the partially bloomed flower bud, the moon hidden behind clouds, etc. There is quote from the Tsurezuregusa stating "Even when building the imperial palace, they always leave one place unfinished". I don't see how not perfectly filed decorations is any indicator of casting whatsoever (If I showed some of my early sukashi tsuba, some might think I knew how to cast iron...). It might be on purpose, it might be a skill or equipment issue.

https://www.comokin.co.jp/shopbrand/004/X/ https://www.tools-shop.net/view/category/g-engaver14 These are the usually recommended sites for tools. I have no idea if they ship abroad. Like Manuel said, most make their own. I have made some tagane with old broken files, after annealing them (it is very time consuming, but rewarding) and a few kisage as well. You can buy tool steel (if you're in France, I don't know the equivalent, but here is the wiki: https://fr.wikipedia.org/wiki/Acier_à_outils).

FYI, from two sets of experiments done in the early 2000s with bladesmiths (published by Prof. Takuo Suzuki), there is little evidence that the "impurity" content (I mean atoms that are not interstitials, like carbon) actually changes with folding. Only the carbon content and the amount/shape/distribution/size of inclusions changes with the folding and forging process. About the effect of composition, it has a clear effect on oxidation, but I am not aware that it changes the colour of polished steel. Forging indeed will give you smaller grains, but then again, how the smith heats the blade prior to quenching will also change this grain size. There was a very nice study in Prof. Morito's team where they managed to show how different the grain size prior to quenching was with different smiths. Also, I thought a lot of the final aspect of the blade depended on the polisher. But here, I have virtually no knowledge. EDIT: All that to say that I think the carbon content, the smith, and the polisher have a larger effect on the final aspect of the blade than the other elements present in minute concentrations.

Can the slight variations in chemical composition really be seen on the blade? There might be slightly faster or slower grain growth due the elements in the steel, but I thought the forging and heat treating process of each smith would have a stronger effect on the final appearance of the sword. By the way, Prof. Ohmura has a page on this various structures of the swords across time/styles: http://ohmura-study.net/008.html

That's the issue with this thread, as raised earlier (and I know I am contributing to the problem, but at this point, it's too late): all the interesting information is hard to find. The reference to that paper (cast sword fitting in brass) has been given at some earlier point. Just like the mention of cast iron items, like chagama, and the process of doing it (cast the cast iron, then decarburize, finish the surface, then patinate it). Cast iron tsuba are currently made by iai equipment maker Nosyudo, but I am not familiar with their process (I suspect it's similar to the one above). Reference on non-ferrous cast tsuba in Nara: 刀装具鋳型の三次元分析からみた近世鋳造技術の研究 (2018 年度科学研究費（奨励研究）研究成果報告書, 研究課題番号：18H00015)

Nice blade! I have one from that forge (in Kumamoto, right?). They are really exceptionally well balanced for iai. Congratulations, enjoy it!

On Instagram, this artisan makes beautiful bags (based in Japan, but may take orders?): https://www.instagram.com/okatanabukuro_waka/

From my understanding, kacchushi tsuba are usually thin, round, and large, with a worked mimi (like uchikaeshi mimi) that is thicker than the ji. Sukashi is usually a bit more elaborate than what is seen on the so-called tosho tsuba. I cannot judge the thickness here, but from the nakago ana, it is a bit small.