Spare systems

To ensure the best possible conversion rate for spares, many players will use a "spare system". This entails using the boards by the foul line and the target arrows to adjust the target line, so that the ball will hit any remaining pins. These systems are not infallible and can be affected by changing lane conditions but they do provide a useful guide to spare shooting. The most popular spare systems are the 2-4-6 and the 3-6-9.

2-4-6 - This system involves a player keeping their feet on the same boards by the foul line, but aiming for different target arrows to modify their strike line for the spare. For instance, if a player has a strike line of 17-10 (feet on board 17, ball delivered over board 10, the second arrow), modifying the strike line to 17-12 should ensure that the ball enters the pocket hitting the 2-pin, instead of the 1-pin (3-pin for left-handers). Similarly, moving the target by four boards should result in a line to the 4-pin for right-handers and the 6-pin for left-handers, while a six board shift will target the 7-pin and 10-pin in each direction respectively.

3-6-9 - In this system, players use the same target arrow, but move their feet by three, six or nine boards along from the approach position of their strike line. If a player moves their feet further to the outside of the lane but aims for the same target, then the ball will enter the pocket further towards the inside of the lane. Using the same strike line as above (17-10), a 14-10 line should ensure a hit on the 2-pin for right-handers, while 11-10 will result in a 4-pin hit, and an 8-10 line should see the ball hitting the 7-pin.