A modern martial art, and also an Olympic sport that was created in 1882 by Prof Jigoro Kano after studying various styles of Jiu-Jitsu. There are three basic categories of Waza ( techniques ) in Judo : Nage-waza (throwing techniques), Katame waza (grappling and submission techniques) and Akemi-waza (striking techniques). A lot of emphasis is placed on free practice, and competition. All techniques are based on the central principles of maximum efficiency and minimum effort which eliminates the need for having brute strength. The techniques can be used by a small person to throw and defend against a much larger and stronger opponent effectively.