The jang tan-do (long daggers in English, sai in Japanese)
was a Korean farm tool used to help plant crops. The "blade" of the
jang tan-do was dragged through the soil creating a furrow in
which seeds were placed and then covered with soil. The jang tan-do
was used during the Japanese occupation period in the 1500's. It became
a formidable weapon for defense against the Japanese samurai warrior.