Ten-pin bowling the body in step one; step two has the ball at the bottom of the backswing; in step three, the ball is at the top of the backswing; finally, the ball is swung forward and delivered in conjunction with the fourth and final slide-step. In a five-step approach, the bowler takes an initial timing step before pushing the ball away from the body. The regulations listed here are generally based around regulations set by the United States Bowling Congress — based on the original rules first codified by a USBC predecessor, the American Bowling Congress in 1895 — and 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