There are games, like Nim, where the point is to get the last play. The player who has no move loses. At first blush, go does not seem like that, because of the pass. Yet pros emphasize the importance of getting the last play at different points of the game. Why is that?

To illustrate the point, let's look at a very simple game with a stack of coupons. Each coupon has a value, called the temperature, such that whoever takes it gets that value. The coupons are stacked in order of temperature with the hottest (most valuable) coupon on top. (Obviously the best play is to take the hottest coupon.) The bottom coupon has a temperature of T0, the next coupon has a temperature of 2*T0, the third has a temperature of 3*T0, etc. Each coupon is a simple gote with a miai value equal to its temperature. We also say that the temperature of the game is the same as the temperature of the hottest coupon. The value of having the move (sente) at temperature, T, is approximately T/2.

As with the stack of coupons, in go the hottest play is normally best, and the value of sente is approximately half the temperature of the hottest play. The last play, however, presents a major exception to those rules of thumb.

Consider the bottom coupon, worth T0. The value of sente at temperature T0 is not T0/2, as it would be if it were not the last coupon, but T0, which is twice that. Now, in the coupon game who gets the last move is determined. But in go, it may be possible to fight over who gets the last play. Suppose, for instance, that Black can maneuver it so that he gets the last play at T0. That is, if it is his turn when the temperature reaches T0, he gets the last play, as usual, for a gain of T0, but if it is White's turn, then White gains T0 but then Black gets the last play at T0 for a net gain of 0 to either player instead of T0 for White. Assuring that he will get the last play is worth, on average, T0/2 for Black.

Now, the very last play of the game is typically small. Gaining half that is not worth much. But what about getting the last play at other points in the game?

Let's look at the coupon game again. Suppose that, as usual, the difference in temperatures between successive coupons is T0, except that after temperature U, the temperature drops to V, where U - V is greater than T0. What is the value of sente at temperature U? It is approximately U - V/2 instead of U/2. The difference is (U - V)/2.

Suppose that we have a similar situation in go, where the temperature drops from U to V. And suppose that Black can maneuver things so that he will get the last play at temperature U. Then if it is his turn when the temperature reaches U, he will gain approximately U - V/2; if it is White's turn, then White will gain approximately V/2. Assuring that he will get the last play at temperature U is worth, on average, U/2. OC, when it is known who will play first at temperature U, then the fight for the last play at temperature U is over U - V/2 versus V/2, or U - V, the drop in temperature.

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The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Thanks, Bill!