There are 10 grades before Black Belt and 10 after. The grades before Black are known as Kyu grades, while the ones after are called Dan grades. There is a popular misconception among Karate students during the early years of Karate training, that being a Black Belt is where Karate ends. In fact, the reality is quite the opposite. Getting a Black Belt is where you truly begin to study Karate.
Originally, there were no grades in Karate at all. It was decided though that grading was a useful technique that helped keep students motivated, especially in the early years of training.