The Tenka'ichi Budokai is a World Martial Arts Tournament on Earth that occurs every five years (which later changes to every three years after the 21st Budokai, then every year after the 26th). The Budokai features the Earth's strongest fighters as well as the regular participation of the Dragon Ball Gang and the Z Fighters. Besides the title of World Martial Arts Champion, the winner of the tournament receives the considerable amount of 500,000 zeni (later increased to ten million zeni) as a prize. It shown that in the 21st and 22nd Budokai, the prize is given to the winner directly after the tournament, while in the 25th Budokai, according to Mr. Satan, they send it by mail.
In the tournament, anyone who comes into contact outside of the ring, is knocked out for more than ten seconds (which is counted by the commentator), or gives up, automatically loses. The tournament used to forbid any use of weapons or protective body gear, but this has changed by the time of the 27th Budokai. Poking someone in the eyes or hitting them in the groin is also not allowed. The most important rule is that killing the opponent is not allowed. Disobeying any of these rules results in disqualification from the tournament. However, more than one villain in the manga has entered the tournament with more interest in killing someone against whom they have a vendetta than in winning the prize.
The tournament has two parts: the preliminaries and the tournament itself, although this changed significantly in the later tournaments. The preliminaries are held indoors and without an audience. In the preliminaries, all the contestants are divided in several groups, usually eight (after the 21stBudokai, more contestants than ever have started entering). These eight groups fight in mini-tournaments with a one-minute time limit for each match (matches that last longer than one minute are decided by points). The eight winners, one of each group, move on to the actual tournament.