The system of coloured belts did not always exist in karate it was adopted from judo more of a means for the sudent to track thier progress. Not all clubs have the same colour belts but all clubs tend to use the counting down of numbers for the Kyu grades (10th to 1st) and up the numbers for the Dan grades (1st to 10th).
See below for BCSKs belt colours and what kyu grade it relates to, click the belt for a link to the related grading syllabus.
10th Kyu - Orange belt with a white stripe
9th Kyu - Orange belt
8th Kyu - Red belt
7th Kyu - Yellow belt
6th Kyu - Green belt
5th Kyu - Blue belt
4th Kyu - Purple belt
2nd Kyu - Brown belt with a white stripe
3rd Kyu - Brown belt
1st Kyu - Brown belt with 2 white stripe
Once the student has passed Black Belt the grades are known as Dan Grades, for example when you first pass you are a black belt first dan. Then comes second dan and so on.