The Sai is a versatile ancient weapon with roots back to China and Indonesai and made popular by Okinawan Kobudo (weapon) practices. Here are some basic principles and concepts for catching controlling and striking counter attacks. Note that the use of the thumb is not practical when practicing with contact and catching because the thumb will be inured. Use of the thumb on center is Ok for specific situations when striking or pressing. Today Sports competitors use the thumb but it is important to note that Sports practices are not real martial arts.