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Most of tsubashi do them themselves, there are videos about making the tools as well on the channel

you can start by studying Ford Hallam's Youtube videos https://www.youtube.com/@FordHallam

https://note.com/katana_case_shi/n/nf87e5c28feb4?magazine_key=m92e5a83d03ce Here's the winning works of last year's NBTHK contest

Izumi no Kami Rai Kinmichi

Just for clarity i was never a student of Ford, except watching his tutorial videos on Youtube i had no relationship with him, i'm pretty much self-taught

Among Ford's students there's also Christoph Kopp from Germany, he just won 3rd Silver in this year's NBSK competition. Seems Kevin is no more active on social media either.

It would be possible to have it done, but there's the serious risk that the patina of the new piece won't really match perfectly the original one, i'd personally leave it as it is. Especially considering that the papers won't match the tsuba anymore, making them useless.

Carbon content is related to utsuri no doubt of that, a 0.45% C can't produce utsuri, while over 0.7% can. Anyway I shared enough of my personal experience and Japanese swordsmiths experience, the readers can decide what they think works better. The topic is already exhaust for me

I don't see any mention to utsuri or hamon in the article, I don't know how can be relative to the utsuri topic. This process shows how grain size changes during cycles of normalizing and annealing. The grain size doesn't affect the appearance on the ji, it might influence the hamon in some degree, but depends on how the yakiire is performed

I would say not a common way to make utsuri, also not much reliable, but it still can work, since the principle is the same, different temperatures when cooling rapidly

Midare utsuri Bo utsuri

Exactly, any form of forging and hardening is a thermocycling, but what he stated in his first post is a series of process of heating and cooling with application of clay prior to the yakiire that would lead to the creation of utsuri. I just want to know where this information comes from and how it should look like when it's done. Because so far the only way I know to create utsuri is by temperature control during yakiire. It's not something I claim, it's been done by several swordsmiths, not only Japanese

Of course any form of hardening is a thermocycling, because it changes the composition of the metal through heating and rapid cooling, what I mean is that specific process you described in your first post. Can you provide an example of blade made that way and how you know that process has been used on it?

I have close to 1TB in my library, you gonna need to be more specific on what you want me to show you. Meanwhile can you show me some examples of what you assume is an utsuri created by thermal cycling?

I already showed several examples, but apparently they're not utsuri? I'm not trying to fight or being petty, just I'm sharing my first hand experience, and those who say I'm wrong provided no evidence of what they're saying.