User: What is the best skill in judo?
Assistant: Judo is a martial art, consistency, and dedication should be your doctrine if you want to succeed. In Japan, you could stay white belt for ten years before reaching the first dan grade, which stands for black belt level 1. This could be a bit disappointing for common standards, so in the rest of the world, to encourage practitioners and demonstrate progress, a belt colors system has been created.

Anyone can practice, at any age. Strength is important in competition, but the real spirit would be to rely on using the strength of the opponent, breaking balance with swift movements, and using your body to block, push, rotate, and endless combinations of posture to conclude the movement by a clean and controlled projection.