Strike (bowling)

With a proper hook, the ball only contacts the 1, 3, 5 and 9 pins (sequentially tinted red) to achieve a strike. All the other pins are knocked down in a chain reaction called pin scatter. This is commonly known as a perfect strike.

Front view:^[1] ball impacts center pocket at "board 17.5"—found by a USBC pin-carry study^[2] to maximize strike probability. The ideal impact point is closer to the center of the head pin than most people think.^[1]

Top view: impacting the head pin at a point found to be optimum to strike.^[2]

A USBC pin carry study found "Board 17.5" to be the ideal ball location to achieve a strike, with higher entry angles (shown) and heavier balls (not graphed) generally providing greater chances of striking.^[2]

The so-called "Rule of 31"—actually an informal guideline—calculates the approximate board on which a ball should exit a particular oil pattern based on the length of the pattern, in order to achieve a strike.

In bowling, a strike means that all of the pins have been knocked down on the first ball roll of a frame. On a bowling scoresheet, a strike is marked by an "X".^[3]

In American nine-pin bowling, a ringer is an equivalent term for knocking down all pins on the first ball of the frame (known as a full house).