But in order to ensure this automatic movement there is one thing absolutely essential, and that is not practice merely, but correct practice and swift practice. And correct swift practice implies not only much repetition, but concentration of mind. If you perform a new movement a hundred times, let us say, without thought, it may be done correctly, but it cannot be done, if correctly, swiftly. Correctness is the first essential, as we said in the chapter on exercise, and always essential; the swiftness in execution comes mainly with practice; so also does the automatic performance of the correct movement. But it is a very easy thing to lose correctness as the speed increases, and with a view to right this we have recommended--after the movement has been completely understood, and learned in some cases part by part--practice before a glass. This, then, is the first essential--namely, to have practised one’s weak points till, though they are still perhaps weak, they are performed with the minimum possible of conscious thought, so that one’s attention, as far as may be, is free to observe the opponent. For a long time before the match continually practise your weak points, till they become, if not satisfactory, at any rate fairly easy, and give to your strong points only that amount of practice which will serve to keep them in repair, so to speak. At the time of the event, of course, you will use them as much as you possibly can, and at the same time give your opponent as few chances as possible of attacking your weaknesses. And the knowledge that you have a passable defence for such weaknesses, and can use it with moderate ease, will vastly increase your measure of confidence, whereas the knowledge that in some one point or so you are nearly defenceless would cramp and worry you throughout the set. Again, since in many cases correctness of striking lies between two opposite faults, it is often useful to practise deliberately the fault which is opposite to your besetting sin. If, for instance, you do not use your wrist enough in a certain stroke, practise using it far more than is in the least advisable; if, on the other hand, you use it too much, not giving the forearm, for instance, its share in the stroke, practise the stroke with the forearm alone, keeping the wrist rigid, and you will often find that you thus attain correctness more quickly than if you had practised correctness. The longest way round, in fact, is here the shortest way home.