The circles represent a QWERTY keyboard layout, and the colours represent letters, so you are being shown how many times various letters appear in a particular thing. In this case, the things are PEOPLE. The top person (brown background) has one O, J and S, and two I, G, H, and Ns. These anagram to a person who has done something imporant in snooker a [BROWN] number of times. Decipher the three people, and you should find out what they've done that number of times. Who should go in the black?