Shuriken (手裏剣, Shuriken), like kunai, are one of the more basic weapons seen in Naruto series. They are sharpened, four-pronged metal stars, useful for throwing. They can also be used for close combat, but not very efficiently. Although small, they can be used to distract, pin down enemy shinobi, or if accurate enough, can kill or incapacitate an enemy. They have an open circle in the centre, useful for grabbing with a finger, to avoid cutting oneself, or to put thread through. The circle is also beneficial to the weapon's overall aerodynamics, ensuring more accurate trajectories.
In addition to the basic shuriken, larger, arm-length shuriken have been seen in the series. They are usually carried on the back or stored in scrolls. As Mizuki and Obito Uchiha demonstrated, these can be used for melee weapons via spinning.
The Fūma Shuriken is of a similar size, but is more lethal and can be folded together for easier storage.
The shuriken of the Land of Birds are a little bit different. They have three-pronged metal stars instead of four.
Toroi of Kumogakure employs the use of slightly angular, square-shaped shuriken of varying sizes, ranging from those similar to the typically observed variant to ones nearly as large as his own person.
Both Darui and Zabuza Momochi has been shown to use shuriken with bent or curved points, slightly resembling Manji.
When the First Division engaged Akatsuki in the Fourth Shinobi World War, Tenten used eight-pointed shuriken.
In the anime, a five-pointed shuriken was shown in a flashback
One of the weapons created by Iō was a useless shuriken that had so many points that it was impossible to grab, as well as being the size and relative shape of a bowling ball.
Another of the weapons created by Iō was a was a giant human-sized rocket-powered shuriken that the 'pilot' was strapped and used a built-in controller to control where it went. However it spun so fast that the user couldn't focus right and would get dizzy and couldn't control it properly.
Tessen Togeito used an unusual semi-circular launcher against Pain's Deva Path, containing a considerable quantity of shuriken, which could be launched simultaneously. This was achieved by holding onto a handle located at the crescent's centre, while pulling out an attached length of chain in a manner similar to a ripcord that caused the shuriken to rotate, before firing the entirety in a single direction.
Toroi used a simple length of cord to thread numerous shuriken together, in such a manner that the entirety could be released and thrown consecutively with just a single motion.