Left-arm orthodox spin is bowled by a left-arm bowler using the fingers to spin the ball anticlockwise. This action is the mirror image of that of an off spinner (a right-arm finger spinner), and causes the ball to turn from right to left from the bowler's perspective, or from the leg side to the off side of a right-handed batsman. It is usually considered to be harder for a right-hander to play against than off spin because of the direction of turn, but easier than leg spin since left-arm spinners generally have a smaller repertoire of delivery types and do not turn the ball as much.
Left-arm orthodox spin is one of the harder bowling styles to master because it requires long hours of practice to get the right line and flight. The bowlers generally attempt to drift the ball in the air into a right-handed batsman, make it dip, and then make the ball spin away from the batsman upon landing. The flight, dip, sharp turn, and drift in the air are potent weapons of the left-arm spin bowler. The major variations of a left-arm spinner are the topspinner (which turns less than expected), the arm ball (which doesn't turn at all), and the left-arm spinner's version of a doosra (which turns the other way). The chinaman (spun with the wrist rather than the fingers, like a leg break) is also a rare variation, especially potent when mixed up with the googly—a great exponent of this was Sir Garfield Sobers of the West Indies. Greater attacking depth can be achieved with the help of variation of amount of spin.