End Games are Delicate
So my first week of end game study begins in earnest. This is a position that is very instructive. It is white to play and win. Take as much time as you need or want to calculate the win. The answer will be in the next paragraph. I would recommend you grabbing a permanent marker and coloring the bottom half of your computer monitor so as not to be tempted to look ahead.
One might be able to brute force calculate a win here. However a seasoned end game veteran would not hesitate at once to play 1. Kf5! Not bothering with annoying things like calculation. The hasty 1. Ke5? throws away the win. Let's look at the variations and then we will get to the point of why a proficient end game player would play Kf5 without even calculating the result.
First we will start with the bad move 1. Ke5?
1. Ke5 Ke7 2. Kf5 Kf7 3. Ke5 Ke7 and white cannot penetrate to win the pawn. Note that 3. Kg5?? actually loses to 3... Ke6.
Now the winning move 1. Kf5! Ke7 2. Ke5 (and now the black king must yield ground) ... Kd7 3. Kf6 Kd8 4. Ke6 Kc7 (Black is trying to ice skate uphill) 5. Ke7 Kc8 6. Kd6 Kb7 7. Kd7 and the pawn is lost. Black can actually retain the opposition but since the white king is ahead of his pawn on the 6th rank it's a win regardless of who has opposition.
The continuation is... 7... Kb8 8. Kxc6 Kc8 (Black now has the opposition but it's meaningless) 9. Kd6 (Kb6 is equally effective with the same idea) Kd8 10. c6 Kc8 11. c7 Kb7 12. Kd7 and white now owns the queen square.
So why, you may ask, would a proficient end game player not hesitate to play Kf5? The answer is simple. White will win the black pawn if his King can arrive at d6, e6 or f6. All his king has to do is reach one of those three squares and the pawn will eventually fall. Armed with this knowledge it is simple to see the ONLY square black cannot guard in this position is f6. White will reach f6 with no problem and that is his immediate plan with Kf5. Go forth and conquer with your new knowledge!
End Games are Weird
Does this position look familiar? It should. It is the exact same position at the top of the page, except it's one rank back. Now with white to move it is a dead draw.
"Hey Weak Square you just said all white has to do to win is to get to one of the three squares beside the pawn, in this case d5, e5 or f5. The white king can clearly get to f5 so why is this a draw?"
First of all, shut up. Clean out your ears. I never said "all" white has to do is get to one of the three squares beside the pawn and he wins. I said the white king has to get to one of the three squares beside the pawn and he will win the pawn, not necessarily the game.
Yes, white will win the black pawn on c5 by force as in the example above. 1. Kf4 Ke6 2. Ke4 Kd6 (If black is feeling particularly generous he can throw away the draw here with 2... Kf6??) 3. Kf5 (Bingo,white has reached one of the three squares, the pawn stands about as much chance as a hot dog in front of Kobayashi). 3... Kd7 4. Ke5 Kc6 5. Ke6 Kc7 6. Kd5 Kb6 7. Kd6 Kb7 8. Kxc5 Kc7.
Ok now black has the opposition, big deal right? He had the opposition in the last example but he could not prevent white from queening. Well unfortunately, my friends, black holds here. This is a basic text book draw. In this case black will not allow the white king to arrive on the 6th rank ahead of his pawn and therefore white cannot win.