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Tenshozan swords


Bruno

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Hi guys,

 

Trying to gather some reliable infos about hamon and forging method of Navy showa-to made with anti-rust steel at the Tenshozan Tarenjo.

 

From what I have read and saw, the swords made at the Tenshozan Tarenjo seems of better quality than those made at he Toyokama arsenal. Early ones are of course usually better.

 

Most I have seen online (never handle any of them) look to have no hamon anymore once "cleaned", and etched/stoned on hamon when in their original polish.

 

It is written that smith and metalurgist Fujiwara Kanenaga was able to obtain a real hamon. Is it confirmed or more a rumor?

 

If true, are we talking about oil quenched or water quenched hamon in his case?

 

Was he the only smith able to do that?

 

I read also that words made at the Tenshozan tarenjo were made by several Seki showa-to smiths, then shipped to the Tenshozan tarenjo to have the final polish and inscriptions/stamp.

 

Is it correct?

 

Finally, are they sunobe-to or do they have a core steel like Mantetsu-to?

 

Thanks for the help

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Bruno,

By the sounds of it, you are the local expert on this! All I've read on it is from Ohmura's website. It seems a study of the hamon on anti-rust blades would need to be done with blades in hand. Off the cuff, I would guess the metalurgical patterns that happen in quenching might result in different appearances in those blades. If you could find some guys that currently forge with stainless steel, like in knife making, they might have some insight.

 

Otherwise, it would be good to start collecting, here, images of stainless blades and their hamon, for comparison and study. But in the 6 years I have been doing this, Tenshozan blades are rare. We see lots of Toyokawa stamped blades, but very few Tenshozan ones.

 

Guys - bring us your Tenshozan blades! And you stainless steel guys - any insight on the hamon characteristics that would help us determine if Tenshozan blades are oil or water quenched?

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Bruno,

I have no information on the stainless steel alloys of WWII sword blades, but as a general information I can say that ledeburitic steels (with a percentage of chromium exceeding 13% in the matrix) do not produce a HAMON. Quenching temperature is much higher than with carbon steels. 

Stainless (or corrosion-resistant) steel was invented in the 1920's, and the early types were not usable for cutting purposes. Later on, the addition of carbon and other alloy elements which were able to form hard carbides in the matrix like Vanadium and others allowed to produce hardenable/quenchable steel alloys.

You can try to differentially harden a stainless steel blade, but this will most probably not result in a HAMON. 

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Thanks for the replies guys.

 

Yes though I am no metallurgist from what I read it is not possible to obtain a hamon with these blades, but at the same time it is said Fujiwara Kanenaga did it, so...

 

I found some Tenzoshan blades pretty well finished for showa-to, and one with a good level if finish (nakago and polish), real hamon and signed by the smith, would make a nice addition to any collection. Even if I am personally versed in gendai-to, I would not be against owning like like that.

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Chris,

 

that looks definitely like a nice HAMON! But as you can see on the NAKAGO, there are traces of corrosion, so I would really like to know what steel alloy they used. There must be a certain amount of carbon in the steel.

That's the thing, I don't know if this is technically anti-rust steel or just a really nice wartime gendaito. The patina is not really indicative of either. I'd have to get it in the hands of someone more knowledgeable.

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Waaaaay back in 2010 I read this about Tenshouzan swords and sent it to a mate.  Note: the link is no longer active.

===============================================================================================================

You will find this an interesting read:
http://www.berfingen.info/alchemyst/military.htm

From the above link they have this to say about Tenshozan swords (scroll to the bottom):
------------------------------------------------------------------------------
Many of the stainless steel (taisabiko or sabinaito) kai-gunto were made at the Tenshozan Tanrenjo in Zushi near Kamakura in Kanagawa prefecture. These blades were made exclusively for the Navy and sold through the Tenshozan store. They are signed on the nakago "Tenshozan Tanrenjo" (see nakago at left) and marked with an anchor stamp. The other main source of blades for the Navy was the Toyokawa Naval Arsenal. Many of these blades are unsigned except for an anchor stamp (different from the Tenshozan stamp) either alone or in a circle or sakura blossom (see common tang stamps above). Stainless steel blades are all considered machine made. Some maybe oil tempered (?), but on most the hamon is purely cosmetic. The Tenshozan Tanrenjo also made Naval dirks.
------------------------------------------------------------------------------

 

===============================================================================================================

 

I also found the following photos and saved them, again waaaay back in 2013:

post-671-0-59760200-1585129415_thumb.jpg   post-671-0-15563000-1585129447_thumb.jpg

post-671-0-83719200-1585129469_thumb.jpgpost-671-0-63984300-1585129488_thumb.jpg

 

And from my archives again here is a prototype Naval Dirk.  I have the photos but no description of any sort.  Perhaps someone here knows of it:

 

post-671-0-50972700-1585129679_thumb.jpg   post-671-0-27588200-1585129708_thumb.jpg

post-671-0-45219800-1585129729_thumb.jpg    post-671-0-53282200-1585129746_thumb.jpg

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A steel that is rust resistant due to a chromium/nickel content, that contains alloying elements that are called carbide formers can be heat treated to form what looks like a Hamon. These days it is normally done by induction heating the portion to be hardened and water quenching.

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  • 1 year later...

Barry's post seems to be the best one for a continuing line on the Tenshozan Tanrenjo mei blades.  I've gotten 16 Tenshozan blades on file now, 13 with the forge mei.  The latest comes from a friend with what may be the first one sighted of it's kind - one with a bohi.  I've seen navy blades with bohi, on rare occasion, but I've searched and cannot see that I've ever come across a Tenshozan Tanrenjo mei blade with one.  Dated March 1942, so the third earliest on file with the anchor stamp and second earliest with the mei.

 

 

5EF764A9-4782-474B-AEFF-B766FFEF543A.jpeg.b50facfb44d608cc562e68604e3d603b.jpeg

25CA1C85-A297-42F1-875B-D19E1FA51A05.thumb.jpeg.08a401c20b3abd95eedef3c37f452711.jpeg

26A84F64-FE8D-464A-9B4F-CD63BAC56875.jpeg.28c6b4e215e4cb0f614cce1c3d5df251.jpeg

EDBDA99B-F040-493B-83FE-E62D3954D717.thumb.jpeg.1d569120511e892190aa2014f1492c59.jpeg

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Well, while this is active I'll simply say I have a Tanrenjo blade in Shingunto koshirae with a mei similar to the one I illustrated back in 2020 (above).  The sword is somewhat of a wreck and I've been 'gunna' write it up for some time now (there is a story!), but a certain teppou write up comes before that, so patience Ladies and Gentlemen...

 

BaZZa

aka Barry 'Gunnadoo' Thomas,

Melbourne, Australia

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On 1/19/2022 at 4:23 PM, Bazza said:

Well, while this is active I'll simply say I have a Tanrenjo blade in Shingunto koshirae with a mei similar to the one I illustrated back in 2020 (above).  The sword is somewhat of a wreck and I've been 'gunna' write it up for some time now (there is a story!), but a certain teppou write up comes before that, so patience Ladies and Gentlemen...

 

BaZZa

aka Barry 'Gunnadoo' Thomas,

Melbourne, Australia

I have the nakago photos of yours, Barry, but not of the whole gunto.  I didn't know where to find the thread I got the pics from or I'd have posted the link.  Here's what I have:

 

995187131_TENSHOZANtachimei4.thumb.jpg.ecbb448b7b69a470fc01c445ba470a77.jpg

1829614623_Tenshozanurameinengo.thumb.jpg.6a9e7d39aa7d5d52f0ca668b163b9da3.jpg

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Bruce P wrote:

>  I have the nakago photos of yours, Barry, but not of the whole gunto.  I didn't know where to find the thread I got the pics from or I'd have posted the link.  Here's what I have:

 

Bruce et al I'm beyond shamed as I completely forgot I'd uploaded those photos!!  Standard territory for this auld bloke ...  I've put it closer to the top of the 'to do' pile in what passes for a brain ...

 

BaZZa.

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  • 9 months later...
On 1/19/2022 at 5:36 AM, Bruce Pennington said:

Dated March 1942

 

昭和十七年五月吉日 A lucky day in May 1942.

 

On 1/19/2022 at 5:36 AM, Bruce Pennington said:

one with a bohi.

 

I know of another one that was sold in Japan that had a fullered blade.  It is anchor stamped and dated 昭和十七年八月日 [a day in August 1942].

http://kako.nipponto.co.jp/swords/KT124416.htm

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That is a very interesting blade/sword and a quality item all up.  The level of workmanship indicated on the blade suggests it could well be Kawamura Eijiro Kanenaga.  He was a brilliant metalwork artist and an innovative metallurgist, doing leading work with stainless steel, referred to as "taisabiko".  He also successfully produced real hamon in stainless steel...which looks like it in the pic?   He typically inscribed blades with mei of this smaller, precise   form,  and also at times used a criss-cross (higaki) yasurime.  Although from Seki he did spend extended periods at Tenshozan Tanrenjo....working and experimenting.  He died in Aug 1943, but only age 57.   This blade is August, 1942.  Its OK to be critical of stainless steel swords as not true nihonto, but in my view Kanenaga was highly skilled and well ahead of his time.  He also early on (1920's-30's) produced unique stainless pocket knives plus exotic articulated insects from iron and other metals.

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  • 6 months later...
On 3/24/2020 at 5:29 PM, ROKUJURO said:

Chris,

that looks definitely like a nice HAMON! But as you can see on the NAKAGO, there are traces of corrosion, so I would really like to know what steel alloy they used. There must be a certain amount of carbon in the steel.

In the ohmura study he quotes 4 different fomulas18 % chromium8%nickle,17% chromium7%1%alloy,16% chromium  and last 13 %chromium with0.3%carbon.This would explain the varied levels of nakago oxidation.amongst other things as well.

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On 3/23/2020 at 9:07 AM, Bruce Pennington said:

Guys - bring us your Tenshozan blades! And you stainless steel guys - any insight on the hamon characteristics that would help us determine if Tenshozan blades are oil or water quenched?

Hey Bruce does that include souvenir swords as well since they also are "tenshozan collected  and toyokawa approved?

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