Kunai is a Japanese weapon originally meant for agriculture in the Tensho Era of Japan. Two well-known varieties of kunai are the short kunai and the large kunai.

Although the kunai is the main tool in the hands of a martial arts expert, it can be used as a multi-purpose weapon, popular until the introduction of firearms. Kunai is usually associated with ninjas who used it to make holes in walls. By attaching the rope to the ring, the user could easily climb walls or trees, which required great accuracy when throwing. The kunai blade was unsharpened from soft iron and was used for digging, forging and breaking wood, plaster and the like, which could probably destroy a tool that had been sharpened or heat-treated.

The kunai used by farmers were slightly smaller than the developed kunai used by ninjas. The kunai was smaller, and there was a small handle with a hole at the top. The farmers inserted their index finger into the hole and grabbed the small handle with their other fingers. The kunai that the ninja used had a larger handle, which allowed them to hold the kunai more effectively. The hole on the kunai was mainly used to tie a rope or rope so that the ninja could hang it by the belt.