8ball and 9ball rules summary Colorado State （8球和九球规则总结科罗拉多州立）.pdfVIP

8-ball and 9-ball rules summary from “The Illustrated Principles of Pool and Billiards” by David G. Alciatore, PhD (“Dr. Dave”) billiards.colostate.edu Presented below is a concise summary of the “official rules of pool,” based on the World Standardized Rules published by the World Pool-Billiard Association (WPA). Figure 1 illustrates the required features of 8-ball and 9-ball racks. In 8-ball, all 15 balls are used, and in 9-ball only the balls numbered 1 through 9 are used. In an 8-ball rack, the only requirements are that the 8-ball must be in the center, one corner ball must be a solid (balls 1 through 7), and the other corner ball must be a stripe (balls 9 through 15). The remaining balls should be distributed randomly (i.e., solids or stripes should not be purposely clustered together), although this is not a requirement. In a 9-ball rack, the only requirements are that the 1-ball must be in front and the 9-ball must be in the center. The lead ball of a rack in both 8-bal and 9-ball is placed directly over the foot spot. stripe 8 1 9 solid 8-ball 9-ball rack rack Figure 1 Proper 8-ball and 9-ball racks The objective of 8-ball is to pocket all of one of the groups (solids or stripes) and then pocket the 8-ball. In 9-ball, the objective is to pocket the 9-ball with the restriction that the lowest num