Sunobe-to

[Bruno]

Dear all,

 

I came across this page about sunobe-to and I am quite interested to understand it, specialy because I have the same sword taken as an example.

 

I do not read Japanese and do not understand very well the english translation .Furthermore, a part of the explanation about sunobe-to is mixed between Japanese and english texts.

 

Can anybody help me please?

 

 

http://www.h4.dion.ne.jp/~t-ohmura/gunto_118.htm

 

Thanks a lot.

[huntershooter]

Bruno;

 

From what I can understand the blade is one piece construction; mill steel or the like, not kobuse/laminated construction.

I THINK they say the blade is oil tempered, though there is mention of water tempering as well.

At any rate, this class of blades would not be considered Nihonto.

[Kevin]

As far as I can make out it, there were a variety of methods but basically it wasn't folded but drawn down (a forging technique) from a modern steel - or a mix of modern steels - and either oil or water hardened. They may or may not have a hamon but due to the lack of folding they won't have a hada. Definitely not traditional.

 

The simplest were made from leaf springs. Leaf springs make very good blades - I've sharpened and used a WW2 blade (a parang) forged from a leaf spring and they are very strong and pretty lethal. He seems to suggest that in some cases sunobe-to were made using orishigane as part of the process. He also seems to be suggesting that one of the reasons behind it was the susceptibility of traditionally made swords to cold fracture in places like northern China. Some of the alloying elements in mill steels reduce the likelihood of cold fracture, as well as increasing the hardness and resilience of the blade and possibly reducing corrosion relative to straight carbon steel.

 

Kevin

[Bruno]

Thank you so much for your answers.

 

This website is really interesting but translation is quite strange to me, the presentation could be a bit improved also!

 

About the presence or lack of a core steel, what do you understand? This part is entirely written in Japanese!

[Tsugio Kawakami]

Usagiya has a little write up on sunobe-to that may be easier to read.

 

http://www.ksky.ne.jp/~sumie99/sunobe.html

[Bruno]

Thanks! I did not know this website before. http://www.ksky.ne.jp/~sumie99/sunobe.html

 

When it says about SUNOBE, made "from one block of modern steel without fold welding", does that mean absence of core steel?

[huntershooter]

Yes it does Bruno.

[Kevin]

Thing to remember is that a modern steel doesn't need folding. Folding and subsequent forge-welding of the folded steel is a way of making the carbon content homogenous, like kneading dough. Modern steels already have a homogenous carbon content, so they don't need folding.

 

Folding however is not the same as lamination. You fold individual elements of a laminated construction to get the carbon content of each bar even all the way through. If the carbon content in a bar is too high in one spot, the metal may be too brittle at that spot, If it is too low, it may not be sufficiently tough. You may, whilst folding, also deliberately burn out some of the carbon to give a lower carbon content steel that is tougher but doesn't get as hard. That would be the bar for your core steel.

 

Having done all that folding, you then laminate several bars together by forge-welding to give a soft core and a hard cutting edge. Laminated construction can get quite complex. You could have a laminate construction with a soft core using unfolded bars of modern steel. However as far as I can make out, sunobe-to didn't have core steel - they were just drawn down. I may be wrong though. It would be quite possible to make a laminated but unfolded block of modern steel and draw it down to give a blade.

 

Kevin

[Kevin]

Actually I'm not sure that the recieved wisdom - namely that sunobe-to don't have core steel - is correct. I have seen a showato that was unfolded but which definitely had core steel. Trouble is, the only way to demonstrate how common this is is to start destroying swords.

 

Kevin

[sanjuro]

It strikes me that the whole issue of sunobi to with all the different classifications and names attached to them, is a veritable minefield for the newbie. Even after reading the article on the Usagiya site, which does go some way toward an explanation, I was still left scratching my head, knowing of the complexities of those classifications.

As Kevin points out there is a grey area with the showa to, and any shinsakuto would immediately be suspect unless the maker and his methods and materials were intimately known.

 

Keith not like things that are not-simple......... Make him head hurt.