The Most Important Square

Ask a dozen chess players what their favorite square is, and quite likely you'll get a dozen of different answers. I suspect all four central squares (d4, d5, e4, and e5) will be on the list. While it is difficult to dispute the importance of the central squares, they are far from a guarantee of winning a game.

Since my childhood, I have remembered the following position:

In his book of selected games, GM Bent Larsen gives a diagram for the final position of the game and says that what he really wants to do is to ask what the knight on d4 was doing all this time?

Meanwhile, there is a truly critical square which can decide the fate of the game with a very high degree of probability. It is the f6-square (f3 for Black)! It is difficult even to mention all the basic mating patterns that happen when one of your pieces or pawns get there. We already discussed the most powerful of them. Sometimes just the threat of your piece reaching f6 decides the game:

Once the knight gets to f6 it will be a checkmate, so Black resigned!

Even if it doesn't lead to immediate checkmate, the occupation of the f6-square usually signifies a huge strategic accomplishment. The reason is very simple: in many cases, Black's only option to defend against the coming attack is to play f7-f5. This important defensive move has two goals: to block the dangerous diagonal b1-h7 and also assure the communication between the flanks using the seventh rank. By establishing a piece or a pawn on f6, you prevent both defensive ideas. Here are two classical twins:

A total lack of communication between the flanks made Black's position completely hopeless in the following, well-known game:

The next game is less known, but I like it even more than Bronstein's game since White's initial sacrifice 14.Nh6!! is very unexpected. The goal of the sacrifice is to establish the same bind by placing the white rook on f6:

These days you cannot discuss any chess related subject without mentioning "The Queen's Gambit." Here is the game where the behind-the-scenes actor GM Vasyl Ivanchuk (who helped Beth Harmon in her decisive game as she followed one of his games to a certain point) takes advantage of the critical f6-square:

As you can see, the secret of a successful attack is quite simple: put one of your pawns or pieces on the f6-square, and crush your opponent!