Shuriken (sword hidden in the hand) are a traditional Japanese concealed weapon that were generally used by shinobi no mono (or ninja, as they are more commonly known) for throwing, and sometimes stabbing or slashing. However, the shuriken took many different shapes and designs during the time that they were used.
Hira-shuriken are constructed from thin, flat plates of metal derived from a variety of sources including hishi-gane (coins), kugi-nuki (carpentry tools), and senban (washers), and generally resemble popular conceptions of shuriken. These are sometimes called “death stars”, “throwing stars” or “ninja stars” as ninjas are consistently seen throwing this which looks like a star . They often have a hole in the center and possess a fairly thin blade sharpened only at the tip. The holes derive from their source in items that had holes - old coins, washers, and nail-removing tools. This proved convenient for the shuriken user, as well, as the weapons could be strung on a string for transport, and the hole also had aerodynamic and weighting effects that aided the flight of the blade after 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.The art of wielding the shuriken is known as shuriken-jutsu, and was mainly taught as a minor part of the martial arts curriculum of many famous schools, such as Yagyu Ryu, Katori Shinto Ryu, Itto Ryu, Kukishin Ryu, and Togakure Ryu. In the modern western world, shuriken can often be purchased online as collector’s items, but in some countries owners must possess a certificate for “knives”.
The Bo-Shuriken a throwing weapon which consisted of a straight, iron or steel spike, usually 4-sided but sometimes round or octagonal in shape. They are usually single-pointed, but there are some that are double-pointed. The length of bo-shuriken ranges from 12 to 21 cm and the average weight was from 35 to 150 grams. 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. This is not to be confused with the kunai, which is a throwing knife.
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 spin before it hits the target.
Bo-shuriken were constructed from a wide variety of 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 to which they appear similar, 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 (utility 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 skilled in a particular method or school.
The origins of the bo-shuriken in Japan are still unclear despite continuing research in this area. This is partly because 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 known mention of a school teaching shuriken-jutsu is Ganritsu Ryu, prevalent during the 1600s. This school utilized a long thin implement with a bulbous head, thought to be derived from the arrow. Existing examples of blades used by this school appear to exhibit an mixture of an arrow’s shape with that of a needle traditionally used in Japanese leatherwork and armor manufacture.
Contrary to popular belief, (video games, Hollywood, anime, etc.) shuriken were not primarily intended as a killing weapon, but rather as a secondary weapon that sometimes played a role supportive to a warrior’s main weapon, usually the sword or spear. Shuriken were primarily used to cause either nuisance or distraction, both being tactics to gain an advantage in battle. Targets were primarily the eyes, face, hands, or the feet, the areas most exposed by a samurai’s armor. Shuriken, especially hira-shuriken, were also used in other novel ways – they might be embedded in the ground, injuring those who stepped on them, or wrapped in fuse to be lit and thrown to cause fire. They can also be used as a handheld striking weapon in close combat.
There are reports of shuriken being coated with poison intended either for a throwing target or for whoever may pick them up when left in a conspicuous place. Other reports indicate that shuriken may have been buried in dirt or animal feces and allowed to rust and harbor the anaerobic bacterium Clostridium tetani – if the point penetrated a victim deeply enough the bacteria would be transferred into the wound, causing a then-incurable tetanus infection.
Shuriken are a simple weapon, but their historical value, thanks to their wide variety of uses and the ready availability of material from which they could be made, has increased. Unlike katana and other bladed weapons, antique shuriken are not often well preserved, largely due to their original status as throwaway weapons.