The Rules Are Set! Soccer Kicks And Stomps Are Illegal
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).
That is what I got from the text, for a full translation of the announcement check this post on the Sherdog forums.
Here is a picture of Yoshihiro Akiyama training with the rules of the event in mind.