Kunai

are a type of shuriken and one of the more basic weapons seen in Naruto. It is a black dagger designed to be 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 also 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.

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 with. Kabuto, when threatening to kill a hospitalized Sasuke in Part I, held a kunai with a curved blade to Sasuke's neck. Also, during the Chūnin Exam, Team Oboro used double-bladed kunai whilst facing Team 7.

Also see

 * Kunai - Real-life Ninja weapon based on a Trowel, a real-life gardening tool.
 * Throwing Knife - Other Knives meant for throwing.
 * Knife Throwing - The Art of Knife Throwing.