Hira Zukuri Katana

[Ethan P. 0]

Hello everyone,

 

There I was, watching knifemaking videos on youtube. when I stumble across Walter Sorrells' channel and promptly made it my business to watch everything there. The last video I watched confused me, though. It was a performance test of a hira zukuri katana he had made, and it stands up to being chopped repeatedly through a 2x4, taking only cosmetic damage.

 

I'm not doubting this test at all, and I have the utmost respect for Mr. Sorrells. The question I have is, if hira zukuri is a perfectly fine blade profile for a long sword, why weren't more of them made?

 

Here's the video:

 

 

Thanks for your thoughts,

 

-Ethan

Edited May 2, 2013 by Ethan P.

[Julian Roche 0]

I think it is the steel limitation? Not everyone in feudal Japan could get the best steel and Walter here is using a modern performance steel; which allows the true potential of the geometry to shine.

 

I honestly have no idea though; it could be simply that not many people knew about this geometric shape

[igrec 0]

Something to read that will explain all : http://www.bugei.com/niku.html

[Howard Clark 6]

The Bugei link above is an excellent article. I believe that one was written by Keith Larman.

[joe pierre 23]

yes, the niku article was definitely keith's work. speaking of keith and howard, here's a nice hira by howard himself:

http://summerchild.com/L6MonsterSale.html

 

as you can see, keith briefly discusses the issue of hira zukuri katana in that posting. the basic idea is that hira blades tend to be thinner, regardless of niku. that makes them nice cutters in our age of tatami tameshigiri, but against armor or other blades (2x4's aren't really so bad in comparison), the geometry made them prone to breaking. and breaking swords was not unusual when these blades were used in combat. the mass of the shinogi-ji on the other hand works as a nice shock absorber.

 

here are a few nihonto to remind us that hira zukuri katana were made, often in earlier koto era work:

http://yakiba.com/Kat_Akihiro.htm

http://www.nihontocraft.com/Hirazukuri_Koto_Katana.htm

 

what i've always wondered is the opposite question -- why hira is the default tanto style and why there are so very few examples of shinogi zukuri tanto (that weren't cut downs). there i suppose the answer is "because they can be" and that by the same reasoning as above, having a shinogi doesn't really help all that much in a tanto. but shobu zukuri tanto aren't unusual at all, so that can't be the only answer.

Edited May 2, 2013 by joe pierre

[B. Norris 13]

I imagine that if Walter Sorrell was cutting armored 2x4's the geometry of the sword he used would be different.

 

As for why hira-zukuri is the default tanto style. There was no reason to put a bunch of (expensive) extra metal into the blade of a knife that is never going to see the types of shock loading that a sword will. A knife lacks the length (or leverage) to generate as much stress as a sword.

 

~Bruce~

[Ethan P. 0]

Thanks for the great link! I was thinking along those lines, but it really puts all the factors into one place.

-Ethan