Ten-pin bowling regulations, identification letters and numbers, and general wear from normal use. For much of the history of bowling, bowling balls were made using a three-piece construction method. Starting in the mid-1990s, however, most manufacturers switched to a two-piece method. In response to these innovative ball designs, the American Bowling Congress placed further restrictions on the technical characteristics of the ball such as the radius of gyration and hooking potential. A game of bowling consists of ten frames. In each frame, the bowler will have two chances to knock down as many pins as possible with their bowling ball. In games
Ten-pin bowling a "shovel-pitch" from the side. A conventional bowling ball is designed to roll about a generally horizontal axis, and often the core is asymmetric so that the ball can hook naturally. However, in parts of Asia, the "spinner", "helicopter" or "UFO" release is more common. A ball spinning about a generally vertical axis of rotation spins like a top down the lane, and slides straighter, regardless of oil pattern. The ball takes an unconventional path along the front pins ("deflection"), creating domino effect pin action. The spin is generated by rotating the hand counter clockwise (right-handed bowlers) until the hand