Hachiwara

The hachiwara  (鉢割) (also kabuto wari or hachi wari), meaning "helmet breaker" or "skull breaker" was a type of knife-shaped weapon, resembling a jitte in many respects. This weapon was carried as a side-arm by the Samurai class of feudal Japan.

Types
Hachiwara were usually around 350mm long, some larger versions are around 450mm long. There were two types of hachiwara:

Dirk type hachiwara
One type of hachiwara was forged with a sharp dirk like point, to parry an opponent's sword, to hook the cords of armor or a helmet, or like a can opener to separate armor plates. The sharp point could pierce unprotected or weak areas of an opponent's armor like the armpit area. The blade of this type of hachiwara was a curved tapered square iron or steel bar with a hook on its back edge. In combat one could parry and catch a blade with that hook, as with a jitte. Some hachiwara of this type were mounted in the style of a tanto with a koshirae.

Truncheon type hachiwara
The other type of hachiwara was a blunt, cast iron or forged truncheon like weapon resembling a tekkan or a jitte. This type of hachiwara had the same basic shape as the dirk type hachiwara including the hook, but it was usually blunt and not meant for stabbing.

Use
It would appear that tales of samurai breaking open a kabuto (helmet) are more folklore than anything else. The hachi (helmet bowl) is the central component of a kabuto, it is made of pie-piece shaped plates of steel or iron riveted together at the sides and at the top to a large, thick grommet of sorts called a tehen-no-kanamono, and at the bottom to a metal strip that encircles the hachi. This would require enormous pressure to split open. This idea that the hachiwara was somehow able to smash or damage a helmet kabuto is most probably a misinterpretation of the name which could have several meanings, as hachi could mean skull or helmet bowl and wari could mean, split, rip,crack or smash.

In modern times there is no Ryū (School, Style) known to train with hachiwara, although certain dojos within Bujinkan Budo Taijutsu still train with them, as an extension of jittejutsu. A number of weapons retailers in Japan still sell usable hachiwara.

Gallery
 Image:Hachi wari.JPG|Antique Japanese hachi wari (hachiwara). Image:Hachi wari 1.JPG|Antique Japanese hachi wari (hachiwara) mounted in a shirasaya. File:Antique Japanese hachiwari (hachiwara or kabutowari) 1.jpg|Antique Japanese hachi wari. Image:Hachi wari 3.JPG|Antique Japanese hachi wari. Close up of the hand guard "tsuba" and the wrapped handle "tsuka"