Rotation, sometimes called rotation pool or 61, is a pocket billiards game, requiring a standard pool table, cue ball and triangular rack of fifteen pool balls, in which the lowest-numbered object ball on the table must be always struck by the cue ball first, to attempt to pocket (pot) numbered balls for points. Rotation is similar in many ways to nine-ball, but its scoring system is not unlike that of snooker and eight-ball.
As with nine-ball and other similar-format games, some attractions of rotation include performing unconventional or difficult shots to reach the correct ball, and quite often making risky attempts to score higher amounts of points by performing advanced shots such as combination shots (plants), bank shots (doubles) and swerves.