The bowler uses a wrist torsion action to spin the ball so that when it pitches it turns from off to leg for a right-handed batsman, i.e. from left to right from the bowler's perspective. The direction of turn mirrors that of a conventional right-handed off spin bowler, however, the ball will usually turn more sharply due to the spin being imparted predominantly by the wrist. Charlie 'Buck' Llewellyn, a South African all-rounder who played at the end of the 19th century, laid claim to inventing the delivery. Some chinaman bowlers occasionally bowl the mirror image of a leg-spinner's "googly" (or "wrong'un" in Australia), which turns in the opposite way in order to trick the batsman. In this instance the ball turns away from the batsman, as if the bowler were an orthodox left-arm spinner. [What is chinaman style bowling in cricket? from Yahoo Answers.]The technique is illustrated here.