Kunai

Kunai are a ballistic ninja weapon, and one of the more basic weapons seen in Naruto. It is a black dagger designed for thrusting and stabbing, though it can still do damage if thrown, and is about the length of one's hand. Many ninja attack by attaching an exploding tag to the blade. The kunai is usually thrown so that it lodges in an object near the target, and then the explosion from the attached tag destroys said target. Kunai can also be kept on spring-loaded wires in the user's sleeve, as seen in Naruto's fight with Sai when they first met. They can be used for close combat, like a normal knife. Empowered with "chakra flow", kunai thrown into targets can cut through solid wood and even solid stone targets.

The ninja appear to use them so much due to both their sturdy and dependable nature and their versatility.

Types of Kunai
Different types of kunai have been seen in the series:
 * Minato Namikaze used three-bladed kunai that had a special seal applied to them in order to perform his Flying Thunder God Technique.
 * During their battle with Hidan, Izumo and Kotetsu used kunai the size of ordinary blades to attack him.
 * Kabuto, when threatening to kill a hospitalized Sasuke in Part I, held a kunai with a curved blade to Sasuke's neck, (seems to be the same type that Rōshi used ).
 * Also, during the Chūnin Exams, Team Oboro used double-bladed kunai while facing Team 7.
 * Another example is that Shiin, used kunai with long, thin, red ropes attached to them.
 * Zaku, before the first test used kunai with holes in the middle and no ring at the end.
 * During the first test an unknown jōnin threw a kunai at a genin who was caught cheating. The kunai with a small ring and fur connected to the ring of the kunai.

Also see

 * Kunai - Real-life ninja weapon based on a Trowel, a real-life gardening tool.
 * Kenjutsu - Real-life armed martial art.
 * Throwing Knife - Other knives meant for throwing.
 * Knife Throwing - The art of knife throwing.