It does not at all follow that the stroke required to drive the object ball into a favourable scoring position following an in-off need be any more difficult than one that would leave it badly placed or lost. Imagine, for example, that the red ball is a little below one of the middle pockets and the cue ball a little above it in quarter-ball position, requiring an aim half-an-inch finer than half-ball. The prudent player, taking a line through the object ball from a quarter of an inch from its edge sees at once that the intended quarter ball stroke would drive the object ball into baulk or under the side cushion according to the amount of strength used. So he gently makes the three-quarter ball stroke instead, aiming half-an-inch full instead of half-an-inch fine, with the result that, upon going to baulk he has the easiest and best of scoring positions to continue with. From the very commencement of his practice the billiard student should cultivate this habit of fore casting the run of the object ball and in so doing the simplest course is to treat every contact with the object ball as though it were a "pot" stroke.