Kunai: Many ninja developed weapons that were merely adapted farming tools, not unlike those used by Shaolin monks in China. Since kunai were cheaply produced farming tools of a decent size and weight, and could be easily sharpened, they were readily available to be converted into simple weapons.
In the mythology of ninja, the kunai is commonly portrayed to be a Japanese knife that is used for throwing. As a weapon it is larger and heavier than a shuriken, and with the grip could also be used in hand to hand combat more readily than a shuriken.
In addition, it could be used for climbing, as either a kind of grappling hook.
There are several varieties of kunai, including of short kunai, long kunai, narrow bladed types, saw-toothed types, and wide bladed types. In some cases, the kunai and the shikoro, a wide bladed saw with a dagger-type handle.