[ Other - Games & Recreation ] Open Question : What are the rules to play Bulls-eye (Darts)?

[ Other - Games & Recreation ] Open Question : What are the rules to play
Bulls-eye (Darts)?

I have a double sided dart board, the first side has the usual dart board
layout (i.e. Classic 20). The reverse side has black and white concentric
lines with the numbers 1 to 9 towards the centre. The centre has a red
bulls-eye, with a white circle around it and a black circle around that.
These three circles don't have point values. If I want to play a simple
game to aim at the bulls-eye, how many points should the bulls-eye and the
two circles around it be worth? Thanks