Jigoro Kano said, "Judo is taught under two methods, one called randori, and the other kata. Randori, or Free Exercise, is practised under conditions of actual contest. It includes throwing, choking, holding down, and bending or twisting the opponent’s arms or legs. The combatants may use whatever tricks they like, provided they do not hurt each other, and obey the general rules of judo etiquette. Kata, which literally means Form, is a formal system of prearranged exercises, including, besides the aforementioned actions, hitting and kicking and the use of weapons, according to rules under which each combatant knows beforehand exactly what his opponent is going to do."
