Translation of Yarennoka! rules provided by Nightmare of Battle:

The rules for the Yarennoka! event have been announced. The bout duration will consist of a 10 minute first round and a 5 minute second round. The judges have to choose a winner if the fight goes the full 15 minutes, so there can be no draws.

Soccer kicks and stomps to the head of a downed opponent will not be allowed, but knees are legal besides in the Fedor vs. Choi fight where they are illegal (probably because of the weight difference).