Shuriken ( lit: "hand hidden blade") is a traditional Japanese concealed weapon that was used for throwing, and sometimes stabbing. They are small, sharpened, hand-held blades made from a variety of everyday items, such as needles, nails, and knives, as well as coins, washers, and other flat plates of metal.
Shuriken were mainly a supplemental weapon to the more commonly used katana (sword) or yari (spear) in a warrior's arsenal, though they often played a pivotal tactical role in battle. The art of wielding the shuriken is known as shuriken-jutsu, and was mainly taught as a minor, or more correctly, a secret part of the martial arts curriculum of many famous schools, such as Yagyu Ryu, Katori Shinto Ryu, Itto Ryu, Kukishin Ryu, and Togakure Ryu.
Shuriken are commonly known in the west as "throwing stars" or "ninja stars". This term hardly does justice to the weapon, however, as the pointed "star" shaped form is but one of many different designs the blades took over the centuries in which they were used.
This is a throwing weapon consisting of a straight, iron or steel spike, usually 4 sided but sometimes round or octagonal. They were usually single-pointed but there are some that are double pointed. The length of bo-shuriken ranges from 12 to 21 cm (5-8 1/2 in) and the average weight was from 35 to 150 grams (1.2-5.4 ounces). The bo-shuriken is thrown in a number of ways, such as overhead, underarm, sideways and rearwards, but in each case, the throw involved the blade sliding out of the hand through the fingers in a smooth, controlled flight.
The major forms of throw are the jiki da-ho (direct hit method), and the han-ten da-ho (turning hit method). These two forms are technically different, in that the former does not allow the blade to spin before it hits the target, while the latter requires that the blade does spin before it hits the target.
Bo-shuriken were constructed from a wide variety of commonly used everyday items, and thus there are many shapes and sizes. Some derive their name from the materials they were fashioned from, such as kugi-gata (nail form), hari-gata (needle form) and tanto-gata (knife form); others are named after the object in which they appear similar to, such as hoko-gata (spear form), matsuba-gata (pine-needle form) while others were simply named after the object that was thrown, such as kankyuto-gata (piercing tool form), kunai-gata (utility tool form), or teppan (plate metal) and biao (pin).
Other items were also thrown as in the fashion of bo-shuriken, such as kogai (ornamental hairpin), kozuka (utlility knife) and hashi (chopsticks), although these items were not associated with any particular school of shuriken-jutsu, rather they were more likely just thrown at opportune moments by a skilled practitioner who was versed in the method of a particular school.
The origins of the bo-shuriken in Japan are still unclear at this stage, despite continuing research in this area. This is partly due to the fact that shuriken-jutsu is a secretive art, and also to the fact that throughout early Japanese history there were actually many independent innovators of the skill of throwing long, thin objects. The earliest mention of a school teaching shuriken-jutsu is Ganritsu Ryu, prevalent during the 1600's. This school utilized a long thin implement with a bulbous head, thought to be derived from the arrow. Existing examples of blades from this school appear to exhibit an amalgamation of the shape of an arrow, and the traditional Japanese needle used in leatherwork and armour manufacture.
There are also earlier mentions in written records such as the Osaka Gunki (Military records of Osaka) of throwing the knife and short sword in battle, and Miyamoto Musashi is said to have won a duel by throwing his short sword at his opponent, killing him.
Some styles of bo-shuriken are known to have been developed independently of any formal school of martial arts; for example there is a famous story of a disabled man called Mori Gentaro Gentatsu who as a child developed the skill of throwing nails at birds, and eventually began his own school after he had earned a reputation as skilled fighter.
Hira shuriken are constructed from thin, flat plates of metal from a variety of sources, such as hishi-gane (coins), kugi-nuki (carpentry tools), senban (washers), and as such do not generally look like what is usually conceived of as the ninja star. Often they have a hole in the center, are only sharpened on the very tips and possess a fairly thin blade. The reason for the hole is that the original source items had holes - old coins, washers, and nail-removing tools, each possessed holes as part of their design. This was found to be convenient for the user of the shuriken, as they could be carried strung together on string, and the hole also had an aerodynamic effect which aided the flight of the blade as it was thrown.
There is a wide variety of forms of hira-shuriken, also known as shaken, and they are now usually identified by the number of points the blades possess. As with bo-shuriken, the various shapes of hira-shuriken were usually representative of a particular school, or region that preferred the use of such shapes, and it is therefore possible to identify the school by the type of blade used.
There are two major forms of throw with hira-shuriken, the overhead throw and the horizontal throw. The arm action of the overhead throw is very similar to that of bo-shuriken, although the blade grip is slightly adapted to accommodate the circular shape of the blade itself. The horizontal throw requires a straight, but supple wrist and relies upon the movement of the whole body toward the target instead of a snapping motion with the arm and wrist to generate power, spin and accuracy.
Likewise with bo-shuriken, tracing back through history to determine the origins of this unique throwing weapon is difficult, if not impossible. It is thought that there are several independent, unrelated precursors to the hira-shuriken, which over time became amalgamated into the general form of weapon art we know today. There is very early mention of the throwing of stones which exhibited a flat, rounded shape, called tsubute, which were commonly used in an early battlefield art called inji-uchi (stone throwing). Inji-uchi focused more on smashing armour and bone, however over time, tsubute eventually were fashioned from iron-stone, and became known as tetsu-tsubute. With the manufacture process, practitioners began to modify the throwing-stone's shape to one more suited to tearing of flesh, and sharp, straight edges were added to the design. It is not known precisely when the material used for the construction of these weapons changed from stone to metal.
Another early mention of throwing items as weapons stems back to China, with the art of coin throwing. Skilled practitioners were said to be able to throw a small Chinese coin powerfully enough to embed them into the plasterwork of walls. The type of throw used for coins was the horizontal wrist throw. The edges of these coins were sometimes sharpened, giving them even more cutting ability. Early Japanese coins were diamond shaped (hishi-gane), and there is also mention of these coins being sharpened and thrown, in the same fashion as the Chinese coin.
Some shaken were specifically designed to have a set number of points, and similar shape to some types of religious artifacts, such as horin. Many traditional martial arts schools contained philosophical and spiritual ties to certain religious organizations, such as Shinto and Mikkyo Buddhism, whose mystical teachings would sometimes play an important role in the activities of their school, so the similarity in design is thought to possibly to show a symbolic connection between them.
In later feudal times, many everyday items were adapted and used for throwing. A skilled practitioner was able to pick up a small hand held object and use it as a throwing weapon. Due to the government prohibition on shuriken jutsu, no doubt the use of common items as weapons was a deliberate attempt to avoid arousing suspicion with the authorities or members of the public who may raise the alarm.
Contrary to popular belief, (video games, Hollywood, etc.) shuriken were not intended as a killing weapon, but rather as a secondary weapon that sometimes played a supportive role to a warrior's main weapon, usually the sword or spear. Shuriken were primarily used to cause either nuisance or distraction, both being tactical methods to gain advantage over the opponent in battle. Generally the target was the eyes, face, hands and the feet.
They were also used, especially hira-shuriken, for a wide variety of other uses, such being embedded in the ground so as to cause pain to those who stepped on them, or to have a fuse wrapped around the points of the blade, to be lit and thrown in order to cause fire, or to be used as a handheld striking weapon when used in close quarters combat with an opponent. There are reports of shuriken being coated with poison, directed at either the person the blade was being thrown at, or to whoever may pick them up when left lying around in conspicuous places. Other reports indicate that shuriken may have been buried in dirt or animal feces and allowed to harbor the anaerobic bacterium Clostridium tetani; if the point penetrated a victim deep enough it would impart the bacteria into the wound and cause a then-incurable deadly tetanus infection.
Shuriken were a simple weapon, but their value was in the wide variety of applications they could be used for, and the ready availability of material in which to fashion the weapon from.