Kama (tool)
The kama is a traditional Japanese farming implement similar to a sickle or billhook used for reaping crops and also employed as a weapon. It is often included in weapon training segments of martial arts. Sometimes referred to as kai or "double kai," kama made with intentionally dull blades for kata demonstration purposes are referred to as kata kai .
History
Before being improvised as a weapon, the kama was widely used throughout Asia to cut crops, mostly rice. It is found in many shapes and forms in Southeast Asia and is particularly common in martial arts from Malaysia, Indonesia and the Philippines. From one or both of these areas, the kama was brought to Okinawa and incorporated into the martial art of te and later karate. It also spawned the use of the kusarigama and the Kyoketsu Shoge.Ellis Amdur criticizes in his book Old School: Essays on Japanese Martial Traditions the theory that the kama was derived from a farmer's sickle. Sickle-like weapons like kamayari however existed since Kamakura period.