Combat Judo Randori

Judo emphasizes a free-style sparring, called randori, as one of its main forms of training. Part of the combat time is spent sparring standing up, called tachi-waza, and the other part on the ground, called ne-waza. Sparring, even subject to safety rules, is much more practically effective than only practicing techniques on their own, which is what jujutsuka were used to doing. Using full strength develops the muscles and cardio-vascular system on the physical side of things, and it develops strategy and reaction time on the mental side of things, and helps the practitioner learn to use techniques against a resisting opponent. A common saying among judoka is "The best training for judo is judo."

There are several types of sparring exercises, such as ju renshu (both judoka attack in a very gentle way where no resistance is applied); and kakari geiko (only one judoka attacks while the other one relies solely on defensive and evasive techniques, but without the use of sheer strength.)