This is the new BJA syllabus for Judo, but from 6th to 5th kyu for adults, 2 minutes of randori is required (full contact). From 5th to 1st kyu, 4 minutes of randori is required, full contact. From 1st kyu to 1st Dan, a person requires 100 points. Points are something like:
10 points for an Ippon win
7 points for a win by Waza-Ari
5 points for a win by Yuko
So to get your first dan you need a minimum of ten wins. These wins come at either grading tournaments or selected competitions. I understand in Karate and TKD though people may look for other attributes than other than the ability to beat their peers. I thought I'd mention the requirements in Judo though just for comparison sake.
"Let your food be your medicine, and your medicine be your food"