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 if synthetic. The top of the pin shall have a uniform arc with a radius of . The USBC also has regulations governing the weight distribution of the pin from top-to-bottom. Pins are allowed one or two "voids" (holes) in the belly area (which can be viewed if the pin is cut in half from top-to-bottom). The voids are needed to balance the narrower top half of the pin with the wider bottom half. Without them, the pins would be too bottom-heavy to fall properly when struck. In addition, a standard regulation pin may lean no more than 10 degrees