A more intricate game requiring more throwing skill and strategy. It is played using primarily the numbers 15 through 20 and the bull's eyes.
At the beginning 15 through 20 and the bull's eye are eligible to be opened. To open a number, a player or team must score three of that number (any combination of singles doubles and triples). Once a team opens a number every subsequent score on that number increases the score for the team. The opposing team may not score on that number. But may attempt to close it by getting three scores on that number.
For example side A scores once on 17. He gets no points but his score accumulates. Side B scores four times on 17 (a double and two singles). The first three scores open the number for B. The fourth score gives B 17 points. Now A strikes 17 three times. The number is now closed for everyone. A gets no points, but does have the satisfaction of not allowing B to get any more points on 17.
In attempting to open and close the bull's eye, the inner is counted as a double and the outer is counted as a single bull.
The game ends when all of the numbers are closed off. However, it may be declared over sooner if the player in the lead closes all possibility of the other side scoring.