Jiyu ippon kumite (自由一本組み手) means controlled kumite with preset rules like kihon ippon kumite but from a free (jiyu) position. While it works the same way like kihon ippon kumite when it comes to the roles and the variety of attacks and reactions it slightly increases the complexity of the situation. Because both opponents can move freely.
In contrast, kihon ippon kumite happens stationary. The partners do not move except the defined motions. In jiyu ippon kumite the behavior like in a real-fight. However, the roles and the attached techniques stay the same.
Jiyu kumite (自由 組み手) means “free” fighting. While it can be conducted in way that it simulates real-life fighting situations, it mostly follows the aim to gain points for attacks. Thus, jiyu kumite does not utilize the full variety of Karate techniques. It mainly focuses on those techniques which are important for “shiai” (試合, tournament matches) like long punches and kicks. Jiyu kumite, therefore, comes close to a duel situation where two opponents, who are trained within the same fighting system like Shotokan, fight against each other. Knee or elbow strikes as well as hooks and hits with the edge of the hand are off limits.
Jiyu Kumite as Shobu Ippon
The major mod, in which jiyu kumite is conducted, is called shobu ippon kumite the major strategy is called ikken hissatsu (一拳必殺) which means killing with one punch. Thus, to gain a point an attacker has to land a punch or kick which must have a devastating effect in the person hit. However, the attacker also have to have control over his action. Because the person hit shall not be seriously become injured eventually.