Chess Strategy/Weak and strong squares

The importance of individual squares
Many amateurs make a mistake in chess. They play for mate, or the win of material, or even the creation of a weak pawn. But many of these amateurs fail to recognize the importance of squares. Seizing squares is just as important as taking pawns, or getting a lead in development, or getting a better minor piece, and so on.

Weak squares
Weak squares are squares which a pawn cannot defend. These weak squares are thus open to occupation by an enemy piece. For White, weak squares can usually be found along the 4th and 3rd ranks, while Black's weak squares are often on the 5th and 6th ranks. One of the qualities of a weak square is that it increases the value of the piece that occupies it. This is especially true for knights, which need advanced support points to be effective.

Let's look at a classic example from the sixth World Champion, Mikhail Botvinnik. On the right is the game Botvinnik—Flohr, Moscow 1936. White here played 33.c5!

This move has a manifold purpose. For one thing, it prepares the queenside attack with b3-b4-b5, and more importantly, it clears a route for the knight to d6 via b1-a3-c4-d6. d6 is White's stronghold and Black's weak point. A knight there would be a thorn in Black's side, and he would feel compelled to hack it off, bequeathing on White a strong, protected, passed pawn. 33...a5 Black stops the advance of the b-pawn, but the knight maneuver cannot be stopped. 34.Nb1 Qf8 35.Na3 Bd8 36.Nc4 Bc7 37.Nd6 The White knight has reached its dream square and dominates the board. Now he has a beautiful position—but what to make of it? Botvinnik gives us an instructive lesson. 37...Rb8 38.Rb1 Qd8 39.b4! So White gets in his advance after all. This is the point—Black can tolerate a knight on d6 by itself. However, by opening a second front against the b-pawn, he forces Black to exchange off the knight on d6, leaving White with a strong, passed pawn. Incidentally, this is another example of the common theme of the principle of two weaknesses. 39...axb4 40.Rxb4 Bxd6 41.exd6 And now White gets his passed pawn, plus pressure against the weak pawns on b7 and e6. 41...Qa5 42.Rdb3 Re8 43.Qe2 Qa8 44.Re3 Kf7 Here White should play 45.Kg1! to take the sting out of Black's next move, but he still won anyway: '''45.Qc4? b5! 46.Qc2 Rxd6 47.cxd6 c5+ 48.Kh3 cxb4''' Although Black has succeeded in taking off the protector of the d-pawn, it is still a strong passed pawn and White is still winning. 49.Qc7+ Kg8 50.d7 Rf8 51.Qd6 h6 52.Qxe6+ Kh7 53.Qe8 b3 54.Qxa8 Rxa8 55.axb5 Rd8 56.Rxb3 Rxd7 57.b6 and Black resigned. The theme of a two-front war held through until the very end—Black was unable to handle both passed pawns at the same time and so capitulated.

Weak complexes of squares
Oftentimes, it is not just a single square that is weak. Sometimes, a whole network of same-colored squares can be weak. These weaknesses can be accentuated by the elimination of the bishop that stands on the color of those squares, because that is one less defensive force for those squares. In a practical game situation, this often occurs when a fianchettoed bishop is exchanged on g7, leaving a complex of weak dark squares on the squares f6-g7-h6, and sometimes the squares f8 and h8. Here is a classic example of such complexes of weak squares.

This is Rubinstein-Salwe, Łódź, 1908. Black is here ready to rectify the dark-squared holes in his position with 15...Nd7 and 16...c5, therefore 15.Bc5! is necessary. White could then continue blockading the dark squares on the queenside: 15...Rfe8 16.Rf2 Nd7 17.Bxe7 Rxe7 18.Qd4 Ree8 19.Bf1 Rec8 20.e3 Qb7 21.Nc5 Nxc5 22.Rxc5 Rc7 23.Rfc2 White has achieved a full blockade of the queenside pawns and the Black pawns are now fixed targets. The dark squares become staging points for the White heavy pieces. Now Black's best was to play 23...a5 to stake out some space of his own. However, Black lost after '''23...Qb6? 24.b4! a6 25.Ra5 Rb8 26.a3 Ra7 27.Rxc6! Qxc6 28.Qxa7''' White won a pawn and soon, the game.

While examining this game I want the reader to realize that not only did Black lose control of the dark squares on the queenside, the weaknesses on them, e.g. d4, c5, a5, and a7, served as strong outposts for White's heavy pieces. On these squares White was able to build up pressure, until something finally cracked and Black lost material. Then, through his pawn advantage, White was able to convert to a win.

"Empty" square complexes
Sometimes, the weak square complexes in the center are not so easily visible. Of course, it is pretty easy to see that Black has enormous dark-square holes with a king on g8, pawns on f7, g6, and h7, with a White queen on h6 and a White bishop on b2. However, sometimes the holes are not easily seen and are not really holes. This most usually occurs in the center, a pawn-free, open center. The principles are still the same, though. Take the next example, Tukmakov—Palatnik, Odessa 1970. 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.a4 Bf5 6.Ne5 e6 7.f3 Bb4 8.Nxc4 Nd5 9.Qd2 c5 10.e4 cxd4 11.Qxd4 Here is a critical opening moment. Black's two pieces are forked. In addition, the pawn on g7 is hanging. What should he do about it? 11...0-0! Of course! Now the captures open the board for Black's pieces to get to the White king. 12.exd5 Nc6 13.Qf4 exd5 14.Qxf5 dxc4 Black has dangerous threats, and the White king is still wide open to Black's rooks. 15.Kf2 Re8 16.Ne4 Qd4+ 17.Be3 Qxb2+ 18.Be2 Nd4 19.Nf6+!? White attempts to regain the initiative. 19...gxf6 20.Qg4+ Kh8 21.Qxd4 Bc3 22.Qxc4 Black would seem to be in trouble. He is a piece down, his kingside pawns are ragged, and White has nearly completed his development, but wait—the idea of the dark squares is still alive! 22...Rxe3! A brilliant move that allows the remaining Black pieces to assume the role of custodians of the dark squares. Although there are no pawns to "outline" the dark squares in the center, they are still there! 23.Kxe3 Re8+ 24.Kf2 Bd4+ 25.Kg3 Qd2! A clever little "quiet" move that continues to follow Black's plan of dominating the dark squares. The threat is 26...Rg8+ and 27...Qh6#. 26.f4 Rxe2 27.Ra3 Rxg2+ 28.Kh3 Rg6 29.Rg3 Rh6+ and White resigned, because Black has an unstoppable attack on the dark squares and mates after 30.Kg4 f5+ 31.Kxf5 Rf6+ 32.Kg4 Qxf4+ 33.Kh3 Rh6+ 34.Kg2 Qf2#.