A kunai (苦無 kunai?) is a Japanese tool, possibly derived from the masonry trowel. There are two widely-recognized variations of the kunai: the short kunai (小苦無 shō-kunai?) and the big kunai (大苦無 dai-kunai?). Although a basic tool, in the hands of a martial arts expert, the kunai could be used as a multi-functional weapon. The kunai is commonly associated with the ninja, who used it to gouge holes in walls. Kunai were originally made to be farming tools but soon evolved into the weaponry they have become today. Many popular manga and ninjutsu characters use kunai as both their primary and secondary weapons.
The kunai was conventionally wrought in lengths ranging from 20 cm to 60 cm, with the average at 40 cm. The kunai was used by peasants as a multi-purpose gardening tool and by workers of stone and masonry. The kunai is not a knife, but something more akin to a crowbar. The blade is made of soft iron, and is left unsharpened because the edges are used to smash (plaster and wood), dig holes, and pry. Normally, only the tip is sharpened.
Kunai normally had a leaf-shaped blade and a handle with a ring on the pommel for attaching a rope. The attached rope allows the kunai's handle to be wrapped to function as a grip, or to be strapped to a stick as a makeshift spear; to be tied to the body for concealment; or to be used as an anchor or piton. Contrary to popular belief, kunai were not designed to be used primarily as throwing weapons. Instead, kunai were primarily non-weapon tools and, when used as weapons, were stabbing and thrusting implements.
Many ninja weapons were adapted from farming tools, not unlike those used by Shaolin monks in China. Since kunai were cheaply-produced farming tools of a decent size and weight and could be easily sharpened, they were readily available to be converted into simple weapons.
As a weapon, the kunai is larger and heavier than a shuriken and with the grip could also be used in hand to hand combat more readily than a shuriken. In addition, it could be used for climbing, either as a kind of grappling hook or as a piton.
There are several varieties of kunai, including short kunai, long kunai, narrow-bladed types, saw-toothed types, and wide-bladed types. In some cases, the kunai and the shikoro, a wide-bladed saw with a dagger-type handle, are difficult if not impossible to distinguish.
As with Ninjutsu, the exaggeration persistent in ninja myths played a large role in creating the current popular culture image of kunai. In the mythology of ninja, the kunai is commonly portrayed as a Japanese knife that is used for throwing as well as for stabbing.
The kunai often appears in manga and anime and video games as a weapon for ninjas (either primary or backup). This is mostly attributed to the very acclaimed anime and manga series, Naruto. The kunai is also used by the Mortal Kombat character, Scorpion.
- Turnbull 2003, p. 61
- Mol, Serge. (2003). Classical Weaponry of Japan: Special Weapons and Tactics of the Martial Arts, p. 123.
- Hatsumi, Masaaki. (1988). Grandmaster of the Togakure Ryū school of Ninjutsu. New York: McGraw-Hill. ISBN 0-8092-4629-5
- Mol, Serge. (2003). Classical Weaponry of Japan: Special Weapons and Tactics of the Martial Arts. Tokyo: Kodansha. ISBN 4-7700-2941-1
- Turnbull, Stephen (2003). Ninja AD 1460–1650. Osprey Publishing. ISBN 978-1-84176-525-9.