All world cup tournaments operates under knockdown karate rules which involves standup bareknuckle fighting with basically no protection.
The more characteristical rules in knockdown karate compered to other styles is that you are not allowed to punch in the face and a point system that only count hits that actually "hurt" the opponent.
This makes knockdown fighting very physical but at the same time quite safe considering that there are very few hits to the head.
After the death of Sosai, IKO was split in different fractions and several has since then started to organise world tournaments in weight categories from 1997 and onwards.
[9] From 1997, the World cup in weight categories has been organized by IKO1[20] led by Shokei Matsui.
Results to be added From 2002, the World Open Tournament has also been organized by IKO3[27] led by Yoshikazu Matsushima.
Kyokushin founder Masutatsu Ōyama first visited Hungary in 1983 and was also involved in overseeing the next two tournaments.