Shuriken (a blade hidden in the hand) is a weapon to throw (occasionally it is used for striking purposes) to hold secretly. They came shaped as nails, needles or stars. Mostly shuriken pieces were made from scrap materials as they were disposable items to use and disappear.
Shuriken-jutsu practices a huge variety of shuriken, all depending on the weight, size, range of precise throw and the way of application during infighting.
Major types of shuriken:
- Bo-shuriken (sticks, single-pointed or pointed at both ends):
- Itiken bo-shuriken (circular section spike pointed at one end) is a 12-15 cm long weapon, 3 to 5 mm in diameter weighing approximately 30 gr. Itiken bo-shuriken is used to throw to 8 m distance; this kind of weapon is very effective in the close combat;
- Niken bo-shuriken (circular section spike pointed at both ends) is nothing to distinguish from the ordinary itiken bo-shuriken but here both ends are pointed;
- Itaken (Taira) (plan section spike – “board blades”) is the classic type of shuriken, which comes as the long flat bar of steel pointed at one side of 2 to 3 mm thick, 1.5 wide and approximately 15 cm long. This is a perfect weapon to throw at 6 m distance which is widely employed for infighting purposes.
- Shaken or hira shuriken (wheel-shaped flat pieces of steel – “wheel blades”) are classified in number of rays and size as follow:
- Happo-shuriken (eight-pointed shuriken). There are five kinds of happo-shuriken:
- 12.5 cm range weapon, weighing about 115 g. This kind of shuriken is not used for close combat, though it is very powerful when throwing vertically or horizontally to 15 m distance;
- 13.5 cm range weapon, weighing about 70 g. This shuriken is used for throwing purposes only. The striking distance ranges to 10 m;
- 6 cm range weapon, weighing about 10 g. It is neither used for throwing to a longer distance nor for close combat due to its low weight. It is normally used as a weapon to shock opponents throwing 10-15 pieces at once in a throw to the enemy's face from a distance of up to 3 m;
- 10.5 cm range weapon, weighing about 60 g. The weapon is of perfect shape to throw both vertically and horizontally to the distance of 12 m. Not used in close combat;
- 8 cm range weapon, weighing about 50 g. This weapon is used to throw by any horizontal or vertical throwing technique, at a distance of up to 6 m, since the opponent might by injured by the short rays of this shuriken. This piece is not used in the close combat.
- Shiho-kongo-shuriken (shuriken of four lightning) is of 10.5 cm range, weighing about 75 g. This shuriken is used for both throwing technique and close combat. The distance for throwing is up to 8 m, and, thus, the throw should be strong enough;
- Shankaku-shuriken (three-pointed shuriken) is of 7.5 cm range, weighing about 25 g. It is rarely used for throwing, though can be successfully used in the close combat (as knuckles);
- Shenban-shuriken resembles a nail washer in shape used to fix the gate boards in the Japan castles of Middle Ages. People having such shuriken on them were not deemed suspicious when inspected, as well as several screws or nails held by anyone else;
- O-shenban-shuriken (square shuriken with incurved sides) of 11.5 cm range, weighing about 75 g. This shuriken is good to use for close combat and throwing at a distance of up to 8 m. A firm and strong throw is required;
- Ko-shenban-shuriken (small square shuriken with incurved ends) of 8 cm range, weighing about 40 g. This is a perfect tool to be used for horizontal throwing at a distance of up to 7 m, but not used in the close-up action due to the shorter spike (finger cuts possible);
- Shikaku-shuriken (four-pointed shuriken) of 10 cm range, weighing about 60 g. This kind of shuriken is good enough to be used for close combat and throwing at a distance of about 10 m;
- Rokkaku-shuriken (six-pointed shuriken) is 11 cm long, weighing about 65 g, easily thrown to up to 12 m. A throw should be strong enough. Not used for close combat;
- Ko-shikaku-shuriken (a small four-pointed shuriken) is of 9 cm long, weighing about 40 g. This shuriken can be thrown horizontally at distance of up to 8 m. Due to its weight this weapon is not used to throw for farther distances. This is rather small for close combat;
- Rokuhoshi-shuriken (hexagonal shuriken) of 8 cm range, weighing about 55 g; this weapon is good to throw at shorter range. Strong throw is required since the weapon leaves minor injury due to the shorter blade length. Not used for close combat;
- Hakkaku-shuriken (octagonal shuriken) of 8 cm range, weighing about 50 g. This weapon is good for any throwing technique (whether horizontal and vertical) at a distance of 10 m. It is not recommended for infighting purpose.
There are different kinds of shuriken among these weapons but rarely used as Manzi-shuriken (gammadion-shaped shuriken), Judzi-shuriken (a cross-shaped shuriken), Gokaku-shuriken (a shuriken in the shape of a five-pointed star), Tatami-Judzi-shuriken (folded shuriken in the shape of a cross), Sanpo-shuriken (triangular shuriken) and so forth.
The phrase that says "Ninja often used shuriken which were previously treated with poison" was mentioned in most Ninja and Ninjutsu-related sources. The authors of these works might suppose secret recipes, but it actually seems much easier.
The two most common poisons to treat shuriken were common rust and dung. In the medieval Japan, where immunization against tetanus or rabies was never practiced, there was high risk to get poisoned with these two substances into the blood. This could result in the longer death in torments to horrify the others and prove the belief in super capacities of night demons.