Sparring is a form of training common to many Martial Arts styles, it is essentially a controlled form of fighting. A set of rules and customs, are in place to reduce the chance of injury to either participant. Sparring is an important part of training as it allows the participants to test their skills against an attacker that is resisting and fighting back.
During sparring sessions participants are usually pared up with students of a similar level of ability, this helps to keep the contest even. But students are free to choose a more experienced partner if they want more of a challenge.
There are various forms of sparring used in Jiu Jitsu two of the most common are -
Randori where participants begin standing with the aim of throwing your opponent to the ground, once on the ground the match becomes a grappling contest.
Katame-Waza or ground fighting is where the participants begin on the ground in a neutral position and grapple to gain an advantage by pinning the opponent to the floor , or by forcing the opponent to submit 'tap out'.
Sparring also represents the sporting aspect of Jiu Jitsu where tournaments can be held consisting if different events and categories.