The Sai
Sai - A pair of short swords called Sai (pronounced "sigh") used defensively against the Bo and Samurai sword. Its design stems from the concept of a pitchfork and was originally developed in Okinawa during the Japanese occupation. Multi-purpose instruments like the Sai became especially useful, since an opponent's weapon could be blocked and/or trapped with one Sai with the other could be used to deliver a thrust to a vulnerable area of the body. Three sai were often carried, with one placed behind the back in the belt, where it could serve as a replacement for a hand-held sai that was thrown at an opponent.
Sai: The Sai should be as long as your elbow to thumb crotch. This karate weapon was first used as a farm tool and later to fight against Samurais and their deadly swords. Sai Techniques: Some of the common uses are to flip it out and strike your enemy, block swords, strike with more power forward with a punch, or backward with an elbow. The sai and jutte were also both used to trap and disarm swordsmen. Sai As A Tool: Originally the Sai were used to measure the distance between seeds in a crop. The Sai was poked into the ground and because of the forked shape it would leave three holes. When it was poked again, the farmer would line up the first and last hole and thus have an evenly spaced crop. After months and years of poking with this tool and flipping, resting, etc. a person could become quite proficient in putting the small point of this karate weapon exactly where he wanted it.