How available was tamahagane?

[Ken-Hawaii]

Of course they did, but where did the original steel come from?

 

One thing I've never read was just how much tamahagane was created in individual tatara, as well as larger (community? school?) ones, way back when. Any good references?

[ROKUJURO]

....One thing I've never read was just how much tamahagane was created in individual tatara, as well as larger (community? school?) ones, way back when.....

Simple answer: It was enough to make all the swords and armour of that period plus all the iron items needed in those times!

 

As the Japanese have always been amazing craftsmen, especially in wood, they could build houses, temples, bridges a.s.o. almost without nails or other iron parts. It is possible that they developed these techniques because iron was rare, but the maritime climate may also have played a role. 

[Ken-Hawaii]

Let's not beg the question, Jean. Yes, of course they made enough, but you know that I'm trying to get a handle on quantities & allocations. Were all tosho busy digging up & separating satetsu, all the time? Were there local "businesses" that provided tamahagane for sale, or did each school handle that? Based on modern tatara, for example, the countryside could be stripped of trees just to make the charcoal, if everyone was doing it.

[Apercus]

Many companies that deal with large scale steel sales or reclaim use portable c Ray florescence equipment to sort materials. The equipment runs about $50 K so there needs to be a justification for the cost. Twenty years or so ago I worked at a company that had the equipment and allowed me to use it on projects. That’s what I used to analyze the Ichimonji. I have the results in a box somewhere but the most significant finding was the lack of impurities. IThere was carbon in the range of .5% to 1% depending on location on the blade and .05% by weight of titanium. There was trace amounts of silicone and absolutely nothing else in the steel that could be detected to five decimal places.

 

Titanium is one of three alloying materials that produces a very small grain structure with thermomechanical processing. That increases both toughness and hardness. The concentration of .05% by weight is considered ideal for this. My current job involves thermomechanical processing as an essential factor in increasing mechanical characteristics of jet engine components. I know something about it.

As a side note, I have gone to a large salvage yard and asked if they could use their equipment to analyze a blade for alloy content. All they need is a small spot of clean metal and about two minutes. Every time I’ve asked they were happy to help. I would be careful with fresh polish. If you were careless you could get a light scratch.

Shannon H

[Ken-Hawaii]

It's amazing that they have X-ray fluorescence guns for sale on eBay for $12K: https://www.ebay.com/itm/BRUKER-S1-TITAN-XRF-Alloys-and-Precious-Metals-analyzer/174079068062

 

Portable, high resolution, what more would we need?

[SAS]

Go for it Ken; you can start a side job.

[Ken-Hawaii]

I'd be tempted if I could figure how to make a profit, Steve. Between my wife & me, we've used analytical equipment for more than 50 years, so semi-automated X-ray fluorescence or diffraction would be a no-brainer.

 

Maybe if I could find a database that identified jidai as a function of what a blade was made of, I could offer a service, but I haven't heard of anything like that. Shannon, have you?

[Apercus]

That would be nice but I suspect there would be a huge amount of variance just within the different schools of any given time period. You would need a data base of readings from blades of known documented smiths across Japan and through out time periods to even begin using x Ray florescence to determine origins.

 

Shannon H

[Ken-Hawaii]

You're absolutely right, Shannon. The data would have to be based on juyo blades, which would identify tosho (in many cases), jidai, & school. But that will still be a snapshot. And I'm not sure whether XRF would be markedly more useful than normal kantei. Ah, well. I'll buy a sword, rather than the XRF.

 

Happy New Decade!

[Bruce Pennington]

For the "What it's Worth" category - If memory serves me, RJT smiths were provided tamahagane by the army and local governers were to supply the charcoal. I wish I could remember where I read that, buy I've lost when and where that was.

 

George Trotter and Chris (Vajo) specialize in RJT and could probably say.

[Emil]

On 12/26/2019 at 9:14 AM, Ken-Hawaii said:

Yes, a great writeup, Jean. Thanks! My original question was raised from reading one of Turnbull's books:

 

"As the fourteenth century gave way to the fifteenth the number of known active swordsmiths jumps to around 3,550, until with the widespread conditions of war in the Sengoku Period (conventionally dated 1467–1603), many swords were being mass-produced, with a consequent loss in artistic quality and an inevitable reduction in strength and durability. Records exist of swords being shipped in their thousands to China, with disputes arising over quality and price."

 

Wit that many active tosho, tamahagane creation must have been massive, yet I've read very little about how that happened.

This can be read in English with the help of chatgtp. I've corresponded some with Mr Ohmura from http://ohmura-study.net/003.html on this topic.

 

Interestingly enough, tamahagane is according to him and the research he quotes an exception rather than the rule in Japanese sword making.

 

Japan has never had enough domestic supply of sword steel to make all the katans needed. Most of time, especially during the production of Koto the steel actually came from China or Korea.

 

I know this is quite a contradiction to the popular belief, so I recommend that you read the article.

 

/ Emil