Bohi - The Specifics

[ken kata]

Hello Guys,

I was always fascinated with the Hi.. (BoHi) .

Often, there was only the general description of "what it is"..

I ask others, and it seems it is not "important", as, they do not address the "non-standard" types of grooves.

 

I was searching and I found this at Markus Sesco's  Translation and Research Services for Japanese Art and Antiques .

Link for those that did not see his site:

 

https://markussesko.com/2015/02/25/kantei-1-sugata-3/

 

This article by Markus has the most info I have seen yet..

 

Photo below..

This is my Tachi.

This is the "  Hi  " ,  I was searching for, to learn more about this style/pattern.

 

Anyone like to add about this short double Hi on the Blade?

I'd like to know, as, I could not find it on that page..

 

Thanks for viewing.

Alton

 

 

 

 

 

 

 

[Hoshi]

From a historical perspective I'm afraid I don't know anything. 

 

However, It's odd from a purely structural and balancing point of view. Bo-hi are there to reduce weight and hence improve the blade's agility without overly compromising structural integrity. If you cut the bohi at the base, you're further putting the weight of the blade down the tip, which is unwieldy. Logically, a partial bo-hi should be cut at the tip or not at all. Could be that specific schools of fencing emphasis forward weight in the blade, which I can't exclude. This leads me to speculate that the bohi on the second blade was done to remove a flaw or a disgraceful horimono. 

[paulb]

Ken

The Hi on your blade are not bo-hi (based on Nagayama definitions. A bo-hi runs the length of thr blade whcih yours clearly do not

The broader one would be better described as koshi-Bi- I quote " A short groove with a rounded top engraved in the lower part of the blade close to the tang"

the other side I cant find but would describe as short Soe-hi or at a push Goma-hashi (chopsticks used at the altar of a shinto shrine) but these are usually wider and deeper.

Unlike Bo-Hi I don't believe thses had any functional value and were there as decoration

[ken kata]

Hi guys..

Thank you Chris..

It was the "Nagayama definitions " stuff I was interested in learning about. ( Just learned that from paulb    )

About the "remove a flaw".. I thought of that too, a while back. Thanks for posting Chris

 

Paulb, leads down a different path/approach.

I was only looking at it from the Bohi side.

 

Wonder if it was to remove little weight, (from the total) in the middle , as, not to disturbed the overall balance?

Too little to be effective for weight savings?

 

Here is my Wakizashi , with similar Koshi Bi ( using my newly learned knowledge already   )..

As decoration, kinda makes the Sword look cool. That is why I bought it..

 

Thanks guys..

Have a safe Saturday Night

Alton

[Ken-Hawaii]

Paul is right, Alton, the smaller hi are decorative, while bo-hi removed weight & increased structural stability of the blade. Wikipedia has a good summary:

 

• • Bo-hi: A continuous straight groove of notable width, known as katana-bi on tantō. With soe-bi, a secondary narrow groove follows the inner straight length of the main one. With tsure-bi, the secondary is similar but continues beyond the straight length.
  • Futasuji-hi: Two parallel grooves.
  • Shobu-hi: A groove shaped like the leaf of an iris plant.
  • Naginata-hi: A miniature bo-hi whose top is oriented opposite from the blade's, and usually accompanied by a soe-hi. Seen primarily on naginatas.
  • Kuichigai-hi: Two thin grooves that run the top half of the blade; the bottom half is denoted by the outer groove stopping halfway while the inner one expands to fill the width.
  • Koshi-hi: A short rounded-top groove found near the bottom of a blade, near to the tang.
  • Kaki-toshi: The groove runs all the way down to the end of the tang.
  • Kaki-nagashi: The groove tapers to a pointed end halfway down the tang.
  • Kaku-dome: The groove stops as a square end within 3 cm of the tang's upper end.
  • Maru-dome: Similar to the kaku, except with a rounded-end.

[groyn]

Usagiya have a useful section on blade grooves. They suggest the short grooves near the tang are prayer-related or representations of Buddha.

 

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

 

Roy