Plus Two System (플러스투 시스템)Reference point and the halfway rule

A system with very little to memorise, used in Korea especially in 앞돌리기 (taking ball 2 from the front and going around via the nearby short cushion) and 비껴치기 (thin, grazing hit on a ball near the cushion) positions. The cue ball goes to the short cushion (1st cushion), the opposite long cushion (2nd cushion) and the long cushion it started from (3rd cushion): short–long–long. Its basis is a single reference point: a ball played into the corner with 2 tips of spin from the point 6 diamonds away from the corner (2 diamonds from the opposite corner) comes back to the same point. Played into the corner from anywhere else, the ball comes back to exactly halfway between the start and the reference point. When the diamonds of the short cushion are aimed at instead of the corner, the arrival is found by adding that diamond's number to the start. It takes its name from the fact that a ball played into the corner from 2 comes back to 4, i.e. '+2' further on. Some players give the same name to the form of the Plus system used for starts very close to the corner; that system is described separately.

When? When the cue ball (or the point where the line from the cue ball to the corner crosses the long cushion) is on the left long cushion and ball 3 is waiting on the same long cushion: in 앞돌리기, 비껴치기 and bricole shots on the short–long–long path.