Judo (meaning "gentle way") is a modern martial art and combat sport created in Japan in 1882 by Jigoro Kano. Its most prominent feature is its competitive element, where the object is to either throw or takedown one's opponent to the ground, immobilize or otherwise subdue one's opponent with a grappling maneuver, or force an opponent to submit by joint locking or by executing a strangle hold or choke. Strikes and thrusts by hands and feet as well as weapons defences are a part of judo, but only in pre-arranged forms (kata) and are not allowed in judo competition or free practice (randori).
The philosophy and subsequent pedagogy developed for judo became the model for other modern Japanese martial arts that developed from koryū (traditional schools). The worldwide spread of judo has led to the development of a number of offshoots such as Sambo and Brazilian Jiu-Jitsu. Practitioners of judo are called judoka.
Judo pedagogy emphasizes randori, literally "taking chaos", but meaning "free practice"). This term covers a variety of forms of practice, and the intensity at which it is carried out varies depending on intent and the level of expertise of the participants. At one extreme, is a compliant style of randori, known as Yakusoku geiko (prearranged practice), in which neither participant offers resistance to their partner's attempts to throw. A related concept is that of Sute geiko (throw-away practice), in which an experienced judoka allows himself to be thrown by his less-experienced partner. At the opposite extreme from yakusoku geiko is the hard style of randori that seeks to emulate the style of Judo seen in competition. While hard randori is the cornerstone of Judo, over-emphasis of the competitive aspect is seen as undesirable by traditionalists if the intent of the randori is to "win" rather than to learn.
Randori is usually limited to either tachi waza (standing techniques) or ne waza (ground work) and, when one partner is thrown in tachi waza randori, practice is resumed with both partners on their feet.