Ten-pin bowling back row, then three, then two, and finally one in the front at the center of the lane. To ease communication, pins are numbered one through ten, starting with "head pin" in front, and ending with ten in the back to the right. Because of the spacing of the pins and the size of the ball (about in diameter), it is impossible for the ball to contact all pins. Therefore, a tactical shot is required, which would result in a chain reaction of pin hitting pin in a process called "pin scatter". In an ideal shot for a right-hander, the
Bowling ball diameter in the range of to . The surface of the ball is required to include markings to indicate the manufacturer's brand name, the name of the ball, the center of gravity (before drilling), the orientation of the core (the Pin), and the axes of the high and/or low radius of gyration (as applicable). Additionally, markings must include an individual serial number and the logo of the USBC. Holes are allowed to be drilled into a bowling ball for a variety of reasons, and bowlers must be able to demonstrate that such holes can be used as claimed. Up to