Sai 15" Black set of 2. Comes with leather wrapped handle. The sai is a traditional weapon used in the martial arts. The basic form of the weapon is that of a pointed, prong shaped metal baton, with two curved prongs projecting from the handle. In Japan it is commonly believed that the sai had a dual purpose, one as a weapon and the other as an tool for the planting of rice There are many types of sai with varying prongs for trapping and blocking.