Kumite
There are many forms of kumite. At our Dojo we practice a few. Each has it's own usefulness in karate training. It is important to note that Master Funakoshi did not endorse full contact free-sparring. It was thought to be violent. Below are a few definitions.
Kihon Ippon Kumite (one step sparring)
Ippon kumite is considered a basic or kihon form of sparring. Each attack, counter-attacking strategy is executed only once before the exchange is stopped. Attacks are still initiated from the basic starting position, front stance - down block (zenkutsu-dachi, gedan-barai), and the counterattacking partner awaits the attack in a natural stance ( shizentai). The attack is announced, the defender shows verbal recognition. Then the attacker lunges with a single technique. The defender blocks then counter strikes. This is done to build upon the skills refined by kihon, or basics. Combining a block and counter against more than an imaginary opponent. As a karateka becomes more advanced foot-work and body position is focused upon more. Kihon Gohon Kumite (five step sparring)
This is similar to kihon ippon kumite. The difference being that the defender blocks the first four attacks then blocks and counters on the fifth.
Jiyu (free sparring)
Jiyu kumite. In this case either partner may attack at any time, using any single or series of techniques, to any single or series of targets. Exchanges are not limited to a single attacking/counter-attack, and the possible combinations of factors including timing, technique, speed, direction, strategy, etc., make the exchanges infinitely varied. This builds upon almost all aspects of karate. It is important to note that even though free sparring does not conform to the rules of Kihon Ippon Kumite or 3 point Kumite, respect for your opponent must be shown at all times. Only give what you expect to get back. If I constantly strike my opponent in the face, I can be most confident that He / She will return the favor.