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
Ten-pin bowling off center without falling. The pins must show the name and mark of the maker, either "USBC Approved" or "BTBA Approved" and appear uniform. The maximum diameter of the ball is and the circumference of the ball must not be more than , and the ball cannot weigh more than 16 pounds (7.26 kg). Generally, the lightest ball available for use is 6 pounds (2.72 kg). The ball must have a smooth surface over its entire circumference except for holes or indentations used for gripping the ball, holes or indentations made to bring the ball back into compliance with weight-distribution