Let’s examine the following position with white to move. What is the best move for white?
Before you laugh, hear me out and the point I’m trying to make!
First off, who has the advantage? Clearly it’s white. White has significantly more material and his king is better placed. Also, the mobility of black’s king is limited. In fact, not only does white have the advantage, the position is won for white.
But note this. Any move by white does not change that fact that the position is won for white. So what objectively is the best move?
Some will point out that white can mate in one with 1. Rh3#, so that is the best move. But why is that the case? What is the specific rationale? Compare 1. Rh3# to the sequence 1. Rc4 Kh2 2. Rh4# Why is mate in one better than mate in two?
There are likely multiple answers to this question. First, mating someone in one move instead of two moves takes less time. And what’s more valuable than time? Also, mating someone in one move instead of two moves takes more energy. And who has extra energy? Thirdly, taking two moves to mate in this position just looks a bit silly. You might be able to come up with other reasons.
Things actually get much worse. For example, white could simply move his rook around aimlessly. For example, 1. Ra3 Kh2 2. Rf3 Kh1 3. Rc3 Kh2 4. Rb3 Kh1 and so forth. Eventually white has to either mate black or the game will be considered a draw.
We now formulate the following basic principles to allow us to determine the best move.
1.1 If you can mate your opponent on the move, then do so.
If we agree on that rule, then we agree on the best move. The best move for white is 1. Rh3#