There are generally two types of bowling: Rolling the ball in a straight line at the pins or “straight ball bowling”, and rolling the ball in a curved or hooking pattern at the pins or “hook ball bowling”. If you want a history of the hook ball, there is an article called Bowling Ball Evolution that goes into detail about how and why hook came about.
From Wikipedia, the free encyclopedia:
A hook in ten-pin bowling is a ball that rolls in a curving pattern (versus straight). The purpose of the hook is to give the ball a better angle at the 1-3 pocket (right-handers) or 1-2 pocket (left-handers.) When a ball is rolled straight, hitting the pocket must be precise. By hooking the ball, the ball will hit the pins with more force, producing better carry – especially on the 5-pin during a strike ball. Straight roll – even when it hits the pocket, will tend to leave a tap, such as the 5-pin on a light hit, or the 10-pin if the ball was just slightly right of the head pin. A hook ball can create strikes with less precise hits at the pocket.
A hook ball can also help the bowler shape the shot on challenging oil patterns.
In other games of bowling, such as duckpin bowling or candlepin bowling, a hook is virtually non-existent for experienced bowlers since the ball is much smaller than in ten-pin bowling, and rolls too fast to the pins to allow a hook to develop.
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