Charles GOREN wrote in his "New Contract Bridge Complete" from 1942:

"I hesitate to use the title "Percentages," as it may frighten off some of my readers. Let me, hasten to explain that no alarm need be felt; this is not to be a lesson in mathematics,

A great many players have the mistaken notion that to be a successful bridge player one must be very good in arithmetic. Nothing could be farther from the truth. Strange to say, in the select circle of bridge experts very few are mathematicians. lf you are able to count thirteen and are willing to exercise ordinary common sense (not that mysterious unknown quantity frequently called card sense), you will not find this chapter difficult to wade through.

"Playing percentages" is another way of saying that where there are two ways to do a thing it is better to select that way which offers you the, greater chance. If the first method offers you three chances of success and the second method offers you only one, obviously the former should he selected. But how are you to determine these chances?

I shall not burden you with the mathematics of the various situations. The mathematicians who have come before us have done all the hard work, and we must take their word for the details.

The simple way to remember their conclusions will be pointed out to you in the succeeding pages.

I should like to point out very early that the principle of percentages‑‑or "the odds," to use a more common expression‑is employed only when there are no other clues as to the distribution of the cards. The things that took place at the table during the bidding and the play are far more important than any abstract probabilities. If, for example, you are concerned with the distribution of five Spades that may be out against you, the probability is that they will be divided three in one hand and two in the other. But if the player to your left has bid a great many Hearts and a great many Diamonds, he will not have room in his hand for many Spades. You must not be surprised if he has only one or even none Spade."