View Full Version : Japanese "Hira Sankaku" Spear Blade Shape

Nathan Scott
8th September 2008, 21:31
Hi all,

I was watching the Military Channel this morning and noticed something interesting regarding a segment on the War of 1812 (1812-1815; between the US and Great Britain). A historian showed a bayonet from this period, which I noticed featured an cross section almost identical to that of the typical Japanese spear tip ("hira sankaku" in Japanese). It was a "flat" triangle in shape, consisting of a long side, which was opposed by a raised "V" shape on the other side. The historian said this shape was later banned from production due to the extensive trauma it caused, and that this type of trauma was very hard to repair. He also stated it was necessary to apply counter pressure against the enemy with the foot in order to extract the bayonet ("hikinuki" in Japanese).

I found it interesting that a European country on the opposite side of Asia from Japan happened to develop a bayonet shape that is basically the same as the Japanese spear blade. There must be something to it I guess.


Max Chouinard
23rd September 2008, 05:06
Well like it was said it causes terribly effective wounds. A flat wound will tend to close itself or at least can be artificially closed more or less easily. A triangular one will not close as much and will be a terrible mess to suture. I've been to a boar hunt some weeks ago and triangular arrows were used; I'll skip the gruesome parts but I can attest of the performance of such a design.

Nathan Scott
4th September 2013, 01:49
Posted below is a freshly polished hira-sankaku spear tip as seen from the front. It features a bohi (groove) along the widest section, and a single shinogi (ridgeline) separating the shorter sections. This photo came out pretty cool in that you feel like you are just about to eat a spear that is being thrust at your face! Note how the wider bottom side curves upwards at the tip, rather than remaining flat like you might expect:


The next image is a shot of the mounted blade next to a "su-yari" (plain spear) style saya. The blade is 3.5" long and 3/4" wide, commonly referred to as an "acorn" spear for obvious reasons. The polisher opted for a fancy "stair step" window pattern above the machi, which is more difficult to apply:


If anyone is curious to see/hear more about this spear, let me know. Otherwise, this is a good example of the triangular spear shape common in many Japanese spears. BTW, this spear tip cuts through paper very easily (the edges are sharpened during polish), leaving a triangular hole (I think technically that qualifies as "tameshigiri" with a spear!)


Meik Skoss
4th September 2013, 11:05
How long is the haft for this spearhead? It looks rather similar to the one I have, which is called an "uchi-e yari." The yarisaki is about 10~11.5 cm. long (I have not measured it precisely) and about 1.5 cm. thick. Evil-looking thing, it will go through just about anything (it evokes thought of AP bullets). The nakago is about 55 cm. long ant the e is about 210 cm. in length. It is made of oak, surrounded by bamboo and wrapped in lacquered paper. The fellow who sold it to me said that the e is almost impossible to break or cut through by a sword (not that I will test that!).

Anent the triangular shape of the spearhead and the wounds such a form causes, I was at the Jefferson Barracks Civil War Museum in St. Louis this past weekend with and saw a number of bayonets made in the same shape. About 35~40 cm. long, with a concave groove on each face. The thought of being injured by such a weapon is very sobering.

4th September 2013, 12:37
Hey Nathan,

I'm sure there are other collectors out there who would love to know a little more about the blade. :)

Nathan Scott
5th September 2013, 03:55
O.K., here are a few more photos and details.

Here is a better shot of the yari blade, which measures: length = 3.5” by width = 3/4”. The blade features: a single ridge line (shinogi) on the top and a single groove (bohi) on the bottom side, which is the widest side; a round neck (kerakubi) with well defined shoulders (machi); and a straight temper line (suhada hamon) that reverses back (kaeri) at the tip (yarisaki) for improved thrusting strength. One thing I noticed is the blade geometry roughly follows the "clamshell edge" (hamaguri-ha) profile concept seen in swords that were designed for penetrating harder objects (armor, etc). Such a shape definitely makes sense for a weapon that is designed to thrust through harder objects (light armor, chain mail, bone, etc). Perhaps this is why the bottom side curves upwards slightly at the tip:


The tang (nakago) is three-times longer than the blade at 9.5", and is rectangular in shape with three retaining pin holes (mekugi-ana):


Here is a not-so-great photo of the signature, which comes back to "Suketoshi", a Shin-shinto Period smith (1781-1860):


Next is an idea of the fittings and haft. The haft (nagaye) is brown red oak (aka-gashi) w/ a black lacquered rectangle pattern, and is fitted for actual combat use (heijo), terminating with an iron pommel (ishizuki) that is of the spear-stand (yari-kake) type. Apparently this type was designed to securely seat the spear into a vertical spear rack. As a side note, vertical spear racks were used for by military applications at places like guard houses and castles, so this type of ishizuki combined with the total length, blade shape, and the understated fittings indicates the spear was likely used to defend some type of place or structure (as opposed to battlefield style or a family heirloom). The blade-mounting section of the haft (tachiuchi) is bound only by a twisted length of hemp cord that is lacquered, and is absent of metal reinforcement fittings (sugjigane) or metal reinforcement collars (dogane).


The blade mounting section of the haft (Tachiuchi) is 2’-2” long. The haft is 7’-2” long, with a total weapon length of 7’-8”. Neither the haft nor the nakago were cut down, which is very nice, and somewhat hard to find in America due to shipping difficulties.

The weapon was restored this year with the excellent and highly recommended services of: Mike Virgadamo (saya-shi), Jeff Vassallo ("Kashu" kuro-ishime saya lacquer), and Woody Hall (blade polisher) - with the kind assistance of Mike Yamasaki (sword expert/dealer).


Nathan Scott
5th September 2013, 04:05
Hi Meik,

Your spear sounds interesting! A 21.5" long nakago is no joke. Is the blade 2-sided or 3-sided?

I've also seen bayonets with the a very similar triangular profile. The design surely was adopted from spear shapes based on their success.


5th September 2013, 20:49
Great photos Nathan! Thanks for sharing!

Meik Skoss
5th September 2013, 20:54
The yarisaki is triangular, quite similar to the one in the photographs you posted. As far as three-sided spearpoints are concerned, as one of the earlier posts mentioned, wounds of that shape are very difficult to heal. One can only imagine how much more difficult they would have been to treat "back in the day." I am not certain about this, but I think I heard that triangular blades were banned by the Geneva Conventions on Land Warfare. If so, I think I can understand why -- those things are nasty!!

Nathan Scott
6th September 2013, 02:33
I think I heard that triangular blades were banned by the Geneva Conventions on Land Warfare

You know, that sounds familiar to me too. I think I learned that somewhere as well.