Chess Strategy/Open lines

Open lines
Open lines are incredibly important in chess. In fact, a game is can be drawn for want of open lines. Why? Because the opposing armies have no way to get in to the other side's position without substantial losses of material! There have been several instances of this. For example, A. Petrosian—Hazai, Schilde 1970, at right.

This position may look composed, but the pawn chains are typical of the King's Indian Defense. Were White to play in this position, he would have no trouble at all in winning with 46.b6!, breaking through. However, it is Black to play, and he is hard-pressed to find a way to stop this advance! If, for example, 45...Kb7, then 46.b6! still wins, because 46...cxb6 47.Qb5 wins due to Black's light-squared weaknesses, also typical of the King's Indian Defense (this should make sense now because we have already discussed weak color-complexes). So, Black must resort to drastic measures. 45...Qb6! Shocking! Black gives up his queen for the knight! However, when you think about it, this makes perfect sense, because the knight is the only piece that could break through the dark-squared bind. And now the queen cannot get in after the game moves: 46.Nxb6+ cxb6 47.h4 gxh4 48.Qd2 h3! Blockading the position completely. After 49.gxh3 h4, the game was clearly drawn and was agreed drawn in six moves. Of course, you can try telling your computer that White isn't better, but it's simply too stubborn!

Note that the lack of open lines in the endgame gave Black the draw. This is one of those rare positions in chess literature, where Black has assumed a full defensive perimeter around his position. Without open lines, although White had a material advantage, there was simply no way to get in and make his extra material felt.

Open and half-open files
These are very important in chess strategy. Half-open files will give your rooks pressure on enemy pawns (if they're your half-open files). For example, in the Open Sicilian, two open files have been created by move 3. 1.e4 c5 2.Nf3 d6 3.d4 cxd4 Now Black has an open c-file and White has an open d-file. Black usually gets some kind of pressure on the queenside, while White gets pressure down the d-file. It's part of both players' respective plans.

Pressure down a half-open file
Pressure down a half-open file can be enormous. Take the following position, from Smyslov—Denker in the USSR vs. USA match:

Black is obviously worse here. Although he has the advantage of the two bishops, in this case it is hardly an advantage, because the dark-squared bishop is totally passive on g7, being blocked out by its pawn chain on d6 and e5. This means that White has light-squared central outposts to work with if the other bishop is exchanged. White has space, but most importantly, a big hole on d5 and a weak pawn on d6 to work with. However, there is no effective way to use these squares right now because Black still has a light-squared bishop defending his holes. Therefore, White played the sensible 25.Bd5! Exchanging off Black's main trump, the bishop pair, and also eliminating the defender of the light squares. As a rule you can deal with a bishop pair by exchanging one of the bishops and creating a more manageable bishop-vs. knight situation, or bishop vs. bishop situation. 25...Kh7 26.Bxe6 Qxe6 27.Rd3 White starts laying siege to Black's d-pawn. '''27...Rc7 28.Rcd1 Rf7 29.Ne4 Bf8 30.Rd5! Qg4 31.R1d3!''' After the immediate 31.Nxd6?, then 31...Bxd6 32.Rxd6 Qxd1+ 33.Rxd1 Rxd1+ holds the endgame. 31...Be7 32.Nxd6 The pawn falls at last. White won on move 52.

Pressure down an open file
Although no pawns lie on an open file, rooks and queens can still exert enormous pressure down it, especially when there are enemy pieces on it. One of the most effective ways to do this is known as Alekhine's Gun, after the following famous game, Alekhine—Nimzowitsch, San Remo 1930. 1.e4 e6 2.d4 d5 3.Nc3 Bb4 4.e5 c5 5.Bd2 Ne7 6.Nb5 Bxd2+ 7.Qxd2 O-O 8.c3 First White secures his long pawn chain. 8...b6 9.f4 Ba6 10.Nf3 Qd7 11.a4 Nbc6 All these moves have been played before, and are still played today. Now Alekhine introduced a novelty (at the time). 12.b4! Breaking open a file that will be used later. 12...cxb4 13.cxb4 Bb7 Black was afraid of some tactics that might of popped up based on b4-b5. 14.Nd6 The knight is now a tower of strength and is actually pretty hard to exchange. It also ensures the domination of the c-file because c8 has been controlled. This is a useful thing to know: The best way to control a file is to control its back rank. 14...f5 15.a5 Nc8 16.Nxb7 Qxb7 17.a6 Qf7 18.Bb5 N8e7 19.O-O h6 20.Rfc1 Rfc8 Not exactly what Black wanted to do, but allowing White domination of the c-file with 19...Nd8 20.Rc7 didn't exactly look appealing either. '''21.Rc2! Qe8 22.Rac1''' Slightly more accurate was 22.Ra3 followed by 23.Rac3 and 24.Qc1. 22...Rab8 23.Qe3 Again, more accurate was 23.Rc3, 24.R1c2 and 25.Qc1. 23...Rc7 24.Rc3! White finally sees the light and invents Alekhine's Gun. The formation rook-rook-queen suddenly pops into his mind. 24...Qd7 25.R1c2 Kf8 Rushing the king over to help in the defense. 26.Qc1 White has established iron control over the c-file and soon wins, accordingly. '''26...Rbc8 27.Ba4! b5''' Sacrificing a pawn in desperation. The threat was 28.b5, winning a piece. 28.Bxb5 Ke8 29.Ba4 Kd8 It seems for a moment that Black has everything covered. However, the resourceful Alekhine realizes that this is only momentary, that Black is in Zugzwang, and thus cannot move at all! He therefore plays the quiet, but brilliant: 30.h4! A waiting move that demonstrates the strength of White's position. However, the more straightforward 30.Nd2, 31.Nb3, and 32.Na5 would have won easily enough. Nevertheless, Alekhine's move made a greater impression on the spectators. Black struggled on for a few more moves, and then realized the nature of his position and resigned.

So in this game, White realized that pawns were not the only things that can be pressured by rooks. Sometimes, you can look for bigger gains and win on the spot.

Penetration on an open file
Penetration is one of the simplest goals of possession of an open file. If you can penetrate down into the enemy position and dominate there, you will have a clear advantage because he will be unable to dislodge you (most of the time) and meanwhile, you can cause chaos in the king's position and the pawns there. Here's a simple endgame example:

Material is level. However, White can assume an immediate advantage with 1.Rc7, dominating the seventh rank and penetrating into the enemy position. Note also, that Black's pawns and king are very weak when the rook is on such a powerful square. Also, Black's rook is driven to passivity after 1...Rb8 2.Kf2 Now the king follows the rook. He will penetrate as well, and the game will be decided by a march of queenside pawns.

Ranks
If files are the means to an end, then the ranks are the end itself. A file is best used when there is a rank down which to penetrate. Most often, this rank is on the first, second, or third (for the opponent). Here is a nice game Vasiliev—Zilberstein, Ukraine 1993.

Black is clearly better because of his outposted knight on e4 and his queenside space advantage. In addition, White has weak light squares. However, all of this is meaningless if Black cannot arrange a breakthrough. So, knowing this, Black plays 16...a5! Creating tension on the a-file. '''17.a3 Ra6! 18.Ne2 Rfa8!''' First Black builds up on the a-file before opening it. Now White is forced to abandon the file. 19.Rab1 axb4 20.axb4 Ra3 21.Ng3 R8a4! Now the rooks make way for the queen. Black is planning to move on to the 2nd rank. 22.Nxe4 dxe4 Now Black also has the d-file cemented under his control. 23.Rf2 Qd3 24.Qc1 Ra2 25.Qe1 Rc2 26.Rd1 Raa2 The "blind pigs" dominate the second rank! White is losing. 27.g3 Bd8 28.Bc1 Rxf2! An elegant queen sacrifice. 29.Rxd3 Rg2+ 30.Kf1 exd3 White resigns, because the rooks dominate the position, especially the second rank. Let's review Black's winning plan:


 * 1. Creating tension on the a-file. (16...a5!)
 * 2. Doubling rooks on the a-file. (17...Ra6 and 18...Rfa8)
 * 3. Opening the a-file and dominating it. (19...axb4 and 20...Ra3)
 * 4. Moving the queen to the new outpost on d3. (23...Qd3)
 * 5. Penetrating on the 2nd rank. (24...Ra2, 25...Rc2, and 26...Raa2)

This plan is typical of such positions, and is a good one to bear in mind.

Diagonals
Diagonals are crucial operating lines for the bishops. Because bishops can only operate diagonally, they need active diagonals in order to be effective. One example should suffice to show the need of bishops for diagonals. A line in the Danish Gambit goes: 1.e4 e5 2.d4 exd4 3.c3 dxc3 4.Bc4 cxb2 5.Bxb2 For two pawns, White has a capital development and two bishops placed optimally on their best diagonals. 5...Bb4+ 6.Nc3 Nf6 7.Nge2 Nxe4?! This move is bad. Although Black is up three pawns now, White's two bishops decide the game in his favor. Black has a horrible development and now exchanges off the only two pieces he has developed. '''8.O-O! Nxc3 9.Nxc3 Bxc3? 10.Bxc3 O-O''' Black undoubtedly thought he would be safe here, because after 11.Qd4 Qf6 there is no mate, and Black is three pawns up. However, White mates after '''11.Qg4! g6 12.Qd4''' and now the power of the bishops shows itself on the open diagonals. The f-pawn is pinned, and otherwise there is no way to prevent mate on g7.

Open lines in the attack on the king
An easy way to create an attack is to first create a weakness. Another easy way to create an attack is to open some lines. However, when you create a weakness, wouldn't it be better to open some attacking lines to the enemy king while you're at it? It would, logically, double the strength of the attack, with weaknesses and lines everywhere, all leading to the enemy king. The following game masterfully shows all of these ideas in action, with a lesson from the sixth World Champion, Mikhail Botvinnik.

Here White played 21.Rd7, which logically penetrates into Black's position on the seventh rank. He eventually went on to win a long, hard endgame. However, he had very little time on his clock. With enough time, everyone was sure that Botvinnik would find the best move, 21.Nf6+! This creates a weakness (on f6), opens a file (the g-file) and opens a diagonal (the long, dark one). In addition, the seventh rank is cleared for the rook's use. Considering that no price is too high for the king, it's a worthwhile sacrifice! 21...gxf6 22.Qg4+ Kh7 23.Rd7! White uses all types of open lines in his attack against the enemy king. 23...Re7 Or 23...Be7 24.Be4+ Kh8 25.Rxe7, with mate to follow. 24.Be4+ f5 25.Bxf5+ Opening more lines for mate. 25...exf5 26.Qxf5+ Kg8 27.Qf6 Ne5 28.Bxe5 Rxe5 29.Qxf7+ Kh8 30.Qh7#. This was an example of a strong attack, preceded by a line-opening sacrifice that created a weakness in Black's king position. It turned out to be enough to win.

Unfortunately, White did not find this incredible winning resource, a winning combination. However, this does not mean that the idea was wrong. The knight sacrifice on f6 is common. It opens lines, specifically the a1-h8 diagonal and the g-file for White's use. It also weakened the seventh rank for the rook to come in and penetrate. Also, the long, light diagonal from b1 to h7 was weakened, and e4 was cleared for the bishop to use that diagonal. After the king was checked about a little, the rook came down and used the all-too common idea of the seventh rank. The rook on the seventh rank played a major role in the attack by delivering the winning blow. In many cases, the rook on the seventh increase the power of such an attack. Then the bishop was sacrificed to open even more lines. Then, using the weak dark squares in Black's position, White was able to mate.