Sunday, October 20, 2013

Random tactics

Before I go on a two week lull and leave y'all to prep for you exams, let's have some more simple tactical training today.

The following 8 (simple) puzzles consist of random tactical motifs and combinations, similar to what you'll be experiencing in a real tournament. It'll be up to you to find and execute them.

So here goes:

Puzzle 1: We'll start with an opening mate in 2 for White

Puzzle 2: Black to move

Puzzle 3: White to mate in 4 with a familiar motif!

Puzzle 4: Black to move and win... be careful!

Puzzle 5: Find that simple winning move for Black

Puzzle 6: White to move and exploit Black's lack of development

Puzzle 7: Use a combination of motifs to let Black mate in 3

Finally, I threw in this composed mate-in-2 just for fun-- it also exploits a simple tactical motif, but not as straightforward as before! Attempt if you have the time:

Puzzle 8: White to move and mate in 2

And thus I leave y'all to concentrate for your exams, so there will be no posts for the next two weeks. All the best! (:

Friday, October 11, 2013

Bishops of similar colour in the endgame: Part 1

Last Monday we came across a very intriguing position that I want to share with y'all:

White to move

If it were Black to move it would be simple... Black is in zugzwang, so whatever move he makes leads to a win for White.

But what if it were White to move? Can White force a win in this position?

Back in June we touched upon the topic of opposite-colour bishops in the endgame and how they usually give drawing chances for the weaker side. So now, in order to gain a better understanding of how to solve the position above, we will look at the topic of similar coloured bishops in the endgame.

(Note: I hope y'all remember the concepts you've learnt about opposite-colour bishops, if not go back and read the articles again: http://nushsblackknights.blogspot.sg/2013/06/opposite-colour-bishops-in-endgame-part.html)

We start with the simple examples:

White to move and win

Over here White has winning chances. Black wants to force a draw by leaving his bishop along the a5-d8 diagonal, thus controlling the queening square-- he can get a draw so long as he manages to trade off his bishop for the opponent's pawn. White, on the other hand, need to find a way to chase the enemy bishop away so that his pawn can queen. The White king cannot cover all the squares along the a5-d8 diagonal, so he needs the help of his bishop.

1. Be5 Kg6 2. Bc7! 1-0

The king and bishop work together to block the diagonal, thus allowing the pawn to queen.

Notice how different this is from a position with opposite-coloured bishops-- over here, the stronger side can utilize his bishop to force his own pawns over squares covered by the enemy bishop because they are on similar-coloured squares. Also, we can see that in the above position, Black's king is too far away to participate in the struggle.

The position below looks similar, but a change of the diagonal gives White more challenges:

White to move and win

Black's plan is still the same: Occupy the h4-d8 diagonal and prevent White's pawn from queening.

But for White, things are now not so straightforward because White's king is on the wrong side of the pawn, so it cannot work with the bishop to block the h4-d8 diagonal. Even if he were to attempt maneuvering his king to e8 in preparation for Be7, Black will simply switch to the other diagonal with Bd8-Ba5 (and possibly even get his king in to join the fray), making things awkward for White.

Thus White will have to adopt another method: Chasing the Black bishop away from the h4-d8 diagonal, and onto the shorter a5-d8 diagonal where it can be blocked with the help of the White king.

1. Ba5 Kg6 2. Bd8

Forcing the Black bishop out of the diagonal.

2... Be1 2. Be7 Ba5 3. Bd6! 1-0

And now Black cannot stop the threat of 5. Bc7, returning to our first example.

...

In our earlier two examples we have seen that the weaker side's king was far away from the fight and thus was not able to provide any help. So what happens when we place the defending King right in the middle of the action?

Dead draw

Yes-- this is a draw, regardless of whoever to move! If White continues along his usual plan of forcing the enemy bishop onto the opposite diagonal, it will not work:

1. Ba5 Bg5 2. Bd8 Bd2 3. Bf6 Ba5 4. Be5 Bb6 1/2-1/2

And White suddenly finds that he can no longer play Bc7, because both the enemy king and bishop cover this critical square!

Now, if he were to try and force the Black bishop away again with Bf6-Bd8, Black will just quickly switch his bishop over to the other diagonal (while exploiting the fact that the White bishop blocks the pawn from queening while after Bd8). Meanwhile, while White is going around trying to do his own fancy maneuvers, Black can simply shuffle his bishop along a5 and b6 (i.e. shuffling along the diagonal) whenever he requires waiting moves, and thus will never run into zugzwang.

Lastly, note that White's king is frozen because it needs to defend the d-pawn.

...

What happens if we shift everything one square to the side, such that the central pawn becomes a bishop-pawn?

Does it even make a difference?

Yes, it makes a difference-- White can now win in this position!

1. Bd5 Bf5 2. Bb7 Bh3 3. Bc8 Bf1 4. Be6 Ba6 5. Bd5! 1-0


And suddenly Black realizes that he is in zugzwang! Moving the bishop off the a6-c8 diagonal allows the enemy pawn to promote, while moving his king to any legal square allows 6. Bc7. Unlike the previous position, he cannot do his "shuffling" trick along the a6-c8 diagonal, because moving to the other two squares along the diagonal will result in the hanging of the bishop.

Simply put, White won as the diagonal was too short for Black to perform his "shuffling" trick. Thus, in positions featuring pawns which are closer to the side of the board (i.e. 3 files or less), the stronger side can force a win by forcing the opponent's bishop onto the shorter diagonal, before landing him into zugzwang. True exploitation of the terrain indeed!

Cos the battlefield is too small for you to win

Similarly, similar-coloured bishop positions featuring knight and rook-pawns will also lead to better winning chances for the stronger side. If you're not convinced, here's another example:

L. Centurini 1847
White to play and win

(Note: See the KnightVision viewer at the bottom of this example if you cannot visualize the position easily)

White follows the plan similar to the previous example:

1. Bh4

The maneuver Bh4-Bf2-Ba7-Bb8 will force the black bishop off the longer diagonal

Now if Black plays a bishop move like 1... Bf4, White wins in a similar fashion as in the previous example:

1... Bf4 2. Bf2 Bh2 3. Ba7 Bf4 4. Bb8 Be3 5. Bg3 Ba7 6. Bf2! and Black is placed in zugzwang due to the lack of safe squares on the short diagonal


But 1... Bf4 aside, Black can trying something more annoying with:

1... Kb5! 2. Bf2 Ka6

And it seems that White can no longer continue with his plan because the enemy king guards a7. But White has another trick up his sleeve:

3. Bc5!

Preparing to swing back to c7

3... Be5

Black will get his king back to c6, but does not do so immediately as 3... Kb5? is met by 4. Ba7!

4. Be7 Kb5 5. Bd8 Kc6

It appears that Black has stopped White's plans again, but now White forces a win with the following maneuver:

6. Bf6! Bf4 7. Bd4

And now the White bishop cannot be stopped from going to a7. The rest of the continuation should be simple to y'all by now:

7... Bh2 8. Ba7 Bf4 9. Bb8 Be3 10. Bg3 Ba7 11. Bf2 1-0

You may be wondering: So 3. Bc5 is a good move that fixes things, but how about 3. Be3 or 3. Bd4? Shouldn't they work out the same way too? Let's take a look:

3. Be3 Bd6 4. Bg5 Kb5 5. Bd8 Kc6 6. Be7 Bh2!
 
And suddenly White finds that he cannot play 7. Bc5 (in an attempt to play 8. Ba7) because of 7... Kxc5! So now we see why 3. Bc5 was the only way to win-- it prevents 3... Bd6 by forcing the black Bishop to move to with g3, f4 or e5. On these squares White can then challenge via Bh4, Bg5 of Bf6, upon which he will be safely away from the enemy king (which is on c6). In contrast, allowing 3... Bb6 means that Black's king will get in the way while White is trying to maneuver his bishop to a7.

See below for a better visualization of the entire thinking process:


As such, Centurini postulated that in such positions where both kings are directly opposing each other, the weaker side can force a draw if his bishop has at least two free squares to move to on both diagonals. On the other hand, if one of the diagonals has less than two free squares for the defending bishop, then the stronger side can usually win by forcing his opponent into zugzwang.

What can we infer from this theory and the examples shown above? Simply put, in positions featuring similar-coloured bishops with the weaker side's king directly in front of its counterpart, the game is usually drawn if the stronger side's pawn is a central (king or queen) pawn. However, if the stronger side's paw is a wing (bishop, knight or rook) pawn, then he can usually force a win as there will be one diagonal upon which the defender has few safe squares to move to.

Now, let us return to our first example and try to apply what we have learnt so far into it:

White to move... can he win?

A quick look at the position tells us a few things: Firstly, the pawn is a central pawn, meaning that there are ample free squares on both diagonals for the weaker side (Black) bishop to shuffle along. Next, Black's king is close to the action. This should be enough to tell us that Black has good chances of getting a draw. So for example the game may continue:

1. Bg6 Kd6 2. Bd3 Ba4

The old "shuffle" trick. And NOT 2... Kd7?? 3. Bb5+! with an instant loss for Black.

3. Kf7

White exploits the temporary absence of the Black bishop from the h5-e8 diagonal to advance his king in to support the pawn. However, Black's king follows him into the opposition:

3... Ke5 4. Kf8 Kf6

Position after 4... Kf6

And now we see something familiar-- it is that theoretically drawn position from our third example! So now it should not be too hard for you to find a draw for Black over here given that you play correctly. I'll toss in a few random bishop moves to illustrate how the draw is reached:



Oh, but do mind that the analysis may not have been extensive enough-- if you can find a way to force a win for White, do inform me (:

...

Let us sum up what we have learnt for today:

  • In bishop + pawn vs bishop of similar colour endgames, where the pawn is on the verge of promotion, the stronger side wins if the weaker side's king is too far away from the main action.
  • In similar positions where the weaker side's king is directly opposite its counterpart and playing an active part in the defense, a draw occurs if the pawn is a central pawn. This is due to the facts that the weaker side's bishop can switch freely between the two diagonals to prevent the pawn from promoting, without fear of running into zugzwang.
  • However, if the pawn is a wing pawn, then the stronger side usually wins. By exploiting the fact that one of the diagonals is too short with few squares (less than two) for the enemy bishop to run to, then he can force his opponent into zugzwang.

The methods through which these results can be achieved have already been described in the examples

In Part 2, we will take a more in depth view of endgame positions featuring bishops of similar colour.

Source:
http://www.cracked.com/article_18765_the-6-most-insane-underdog-stories-in-history-battle.html
"Silman's Complete Endgame Course" by Jeremy Silman

Monday, October 7, 2013

The story of Iron Tigran: Part 3

In Part 3 of my "Art of successful defense" series (http://www.nushsblackknights.blogspot.sg/2013/09/the-art-of-successful-defense-part-3.html) I introduced the concept of blockade as an effective tool for defense, alongside a famous example by Petrosian. True enough, Iron Tigran was a specialist in the concepts of blockade and prophylaxis and could turn many seemingly lost positions into draws, or equal positions into wins. The following game is another striking example of how Petrosian utilizes a positional exchange sacrifice to carry out a successful blockade, thus turning the tables on his opponent:

Lev Polugaesky vs Tigran Petrosian
USSR Championship, Moscow 1983



1. Nf3 g6
2. d4 Bg7
3. c4 d6
4. Nc3 e5
5. e4 Nc6
6. dxe5 Nxe5
7. Nd4 a6
8. Be2 c5
9. Nc2 Be6
10. Nd5 Bxd5

The centralized knight on d5 exerts a large influence over the squares in Black's camp, so Black wants to eliminate this threat as quickly as possible.

11. exd5 Ne7
12. O-O O-O
13. Rb1 (D)


At this point Black has the more active pieces-- his b7 bishop and his centralized e5 knight. However, White has plans of his own against the queenside.

13... Nf5
14. b4 cxb4
15. Rxb4 Qc7
16. Bb2 Rfe8
17. Nd4 Nxd4
18. Bxd4 Nd7
19. Be3 (D)


Here it seems that Black is in a bit of trouble-- White is advancing down the queenside, and may threaten to push c5 later on, dismantling Black's queenside pawn structure and possibly even creating a passed pawn. But Petrosian has a trick up his sleeve. If you have followed me closely through the "Art of successful defense" series, you should not find it too difficult to spot the next move...
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19... Rxe3!
20. fxe3 Nc5

Blockading the c pawn. There are three main factors which justify this exchange sacrifice:

1. The white rooks have no activity. There are no open files for them to seize, and Black controls the only open file in the game. Although they do sit on semi-open files, the b7 and f7 points are not easy to break through at this stage of the game.

2. White has no good pawn breaks. Because of the blockade he can never play c5, or use his pawns to help the rooks in attacking b7 or f7. In fact, his e3 pawn may be considered as backward, for it cannot advance for fear of instant death (21. d4? Nxd4!). Later on in the game White may have to expend resources and material trying to defend this weak e3 pawn.

3. There are opposite coloured bishops, and White is at the losing end over here. White's bishop can be considered bad as he is blocked by the c4 and d5 pawns, while on the other hand Black's bishop sits brazenly on an open diagonal. Note that Petrosian has given up his rook for White's dark-squared bishop, which may otherwise have helped in overturning the blockade on the c5 square (which is a dark square). Now, White's light-squared bishop does not exert any control over c5, so it is unable to help in chasing off the blockading knight.

Note that if Black had instead chosen to blockade immediately with 19... Nc5, White could simply roll over the defences with 20. Bxc5 dxc5 21. d6! Qd7 22. Rb6 (D)

Position after 22. Rb6

Over here White has a passed pawn, while Black has a weak pawn on b7 which may become a vulnerable target of attack. After 23. Bf3 or 23. Bg4 the light-squared bishop becomes an active piece that hits upon the weaknesses in Black's camp. White will then concentrate on diverting the enemy's forces into defending the weak point b7, while he will slowly advance his passed pawn to victory.

Note that even if Black had chosen not to play 19... Rxe3 or 19... Nc5 and looked for another alternative, he will still face moves like Qb3 or Rfb1, which will capitalize on attacking the b7 square. Thus we see another reasoning behind the 19... Rxe3 sacrifice-- it disrupts White's plans for attacking b7, and the dynamism leaks out of his position. On the other hand, Black will now focus on piling his attacks upon the weak e3 pawn-- once he has broken through (with a move like ...Bxe3), he can then exploit the weak dark squares around the white king to create an unstoppable attack.

Thus, returning to the position after 20...Nc5:

Position after 20... Nc5

Once again we see that because of the blockade, White has no good plan apart from trying to defend his weak e3 pawn:

21. Qc2 Re8
22. Rf3 Bh6
23. Qc3 Qe7
24. Rb6? (D)

Find the best move for Black

Polugaevsky was hoping for 24... Bxe3+ 25. Rxe3 Qxe3+ 26. Qxe3 Rxe3 27. Kf1, after which the double threat of 28. Rxb7 and 28. Rxd6 gives him room for counterplay. However, in his haste he missed a terrible blow...
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24...Na4!
0-1

A short but valuable game illustrating the power of blockade and the exchange sacrifice.

Now I intended to end off my series on Petrosian over here, but I've been looking through so many great games of his, I cannot resist showing you one more. So I guess I'll have to add in a Part 4 then...

Links:
Part 1: http://nushsblackknights.blogspot.com/2013/09/the-story-of-iron-tigran-part-1.html
Part 2: http://nushsblackknights.blogspot.com/2013/10/the-story-of-iron-tigran-part-2.html

Sources:
"The Giants of Strategy" by Neil Macdonald

Sunday, October 6, 2013

The right time to castle?

Every player knows the golden rule of castling as as early as you can. It is drummed into us when we study the basic rules of development, that His Majesty desires a safe command post at the side of the board. Over there he is well protected by his pieces and pawns, as compared to the centre where he is often exposed to enemy attack (see my article "How to Attack: Part 1" featuring the attack against an uncastled king: http://nushsblackknights.blogspot.sg/2013/08/how-to-attack-part-1.html)

But as always, there are exceptions to these rule. In his classic work "Art of Attack in Chess", Vladimir Vuković points out the special situations in which a player may choose to postpone castling, or not castle at all:


1. Castling is postponed or not carried out at all in favour of some other useful actions, such as an early attack

Reasons like capturing an opponent's piece or ruining his pawn structure,which may benefit you more than castling. Or sometimes, when one is confident that his attack is strong enough to break down the opponent's position quickly enough, then he may choose not to castle simply because he does not want to waste time. I know of players who choose to castle late/not castle at all in favour of an early attack.

Remember this position?

Meesen vs H. Muller
Correspondence Game 1928
Position after 10. b3

Yep, it's the same position I showed as the very first example in my "How to attack" series! It is Black's turn, and he can choose to castle on either wing. But because he has the more active pieces, coupled with the vulnerable position of White's king, Black decides not to waste time and launch his attack straightaway:

10... d4! 11. Qxd4 (11. Bxc6+ and Black wins a piece with ...Bxc3+ and ...Bxa1) Rd8 12. Bxc6+ Kf8 13. Bd5 Rxd5! 0-1

White resigned since 14. cxd5 leads to 14... Qxe2#. By choosing to attack rather than castle, Black manages to bring a quick end to the game.


2. Castling is postponed because for the time being it is too dangerous

Thus it would be more logical to eliminate the opponent's threats first before castling. A simple example can be shown in the hypothetical position afrer 1. d4 d5 2. Bf4 Nc6 3. e3 e6 4. Nc3 Be7 5. Nf3 Nf6 6. Bb5. Here Black has the choice to castle kingside, but after 6... O-O White can damage Black's pawn structure by playing 7. Bxc6. Hence if Black wishes to retain his pawn structure he will choose to postpone castling by playing 6... Be7 followed by O-O later on.

Another example follows after the moves 1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. d3 Nf6 5. Bg5 h6 6. Bh4 d6 (D)

Position after 6...d6

Here, to play 7. O-O? will be premature and incorrect, for it allows Black to reply with 7... g5! following with a pawn avalanche against White's kingside; this threat must be prevented before White can safely castle. On the other hand, if White were to play another developing move such as 7. Nc3, and then Black still attempts an attack with 7... g5 and 8... h5?!, the attack will be less dangerous because White has yet to castle. In fact, White could even get out of harm's way by castling queenside later on!


3. Castling is postponed when one wishes to create favourable attacking/defending conditions-- for example, he can delay till his opponent castles, before deciding which side to castle on.

Remember what I said in Part 2 of my "How To Attack" series (http://nushsblackknights.blogspot.sg/2013/08/how-to-attack-part-2.html) regarding the castled position? When the king is still in the centre, he is free to choose whether to castle kingside, queenside or remain in the centre. But after castling, he has already committed himself to a protective shelter on one side of the board, and it is difficult to change the nature of this feature throughout the game.

That is why sometimes, a player may choose to delay castling until his opponent castles first, because he wants to see which side of the board the opponent has been committed to before making his own decision on which wing to castle on. If he is aiming for an attack, he will most likely castle on the opposite wing; if instead he wants to avoid being attacked, he will castle on the same side as his opponent.

Such delays usually occur in typical Sicilian positions like this:

Position after Black's 7th move

It is White's turn, and he can choose to play 8. O-O. But by doing this he will find it difficult to attack his opponent after Black plays 8... O-O, for his king gets into the way of the attacking White pieces. Thus, rather than castling straightaway, he makes further preparations to castle on the opposite wing-- for example by playing 8. Qe2 followed by 9. O-O-O, in which his pieces get maximum freedom to attack Black's kingside.

Here's another interesting example:

Source Unknown
White to move

Once again, White can choose to castle kingside immediately, but by doing this he allows Black to castle kingside too, thus averting the chances of White launching a strong attack. So perhaps he should play 1. Qd2 and 2. O-O-O later on?  But what if after 2. O-O-O Black replies with O-O-O, and then White suddenly finds that he cannot launch an attack without compromising his own king's position?

So the best choice for White will be to play 1. Qe2/Qd2 first, and let Black decide which wing to castle on. If 1... O-O then 2. O-O-O, or if 1... O-O-O then 2. O-O. White castles on the opposite wing from his opponent in order to get the maximum freedom while carrying out his attack.


4. Castling may be postponed or even abandoned altogether when the centre is permanently blocked

In positions where the pawns obstruct the centre such that it is impossible to break through in that theater, the most logical plan for both sides will be to launch their attacks along the wings. In such a case, the kings will actually be safer in the centre (at least for the time being) as compared to when they are on the side of the board!

We look back to our previous example:

I'm back! (:

After 1. Qe2, the most logical reply for Black is also a postponement of castling. Notice something interesting about the position-- the structure of the pawns is such that the centre is blocked; Black has a potential outpost on e4, but it is almost impossible to get his knight there. As a result attacks can only be conducted along the wings, thus the kings are safer in the middle of the board for now. Thus the game might continue as follows:

1. Qe2 Nd8 2. h3 Nf7 3. Qd2 O-O-O

Here Black can safely castle queenside; if White continues 4. O-O-O the possibility of a flank attack disappears, while if 4. O-O Black can launch his own counterthreat with 4... Rfg8, threatening 5... g5.

Although over here the preliminary skirmish has ended with castling, there are also other cases where the centre is so clogged up, the kings choose to stay in the middle throughout the course of the game.


5. Castling is unnecessary when the endgame is already not far off, in which the king will be better placed in the centre of the board

The statement speaks for itself; I guess I don't really need examples to help illustrate the point.

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And these are a few cases in which the postponement or total abandoning of castling can be justified. However, to decide whether or not to castle, or when is the right time to castle, ultimately lies on the player's own judgement and the features of the position itself.

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Oh, and one final hint: Even if you do have justifications to postpone castling, it is always good to get ready to castle anytime, so that you can do it quickly if the situation around the king's central position gets too hot. There can be a big difference in spending one or two tempi , especially when your opponent is attacking you. Thus, the best policy for one will be to get ready to castle as soon as possible (i.e. clear all your other pieces off the back rank), before deciding whether it should be postponed or not.

Sources:
"Art of Attack in Chess" by Vladimir Vuković

Friday, October 4, 2013

The story of Iron Tigran: Part 2

Petrosian was a master of strategy. No doubt his tactical skills were not on par as some of the great tacticians of his time, but his ability to plan several moves ahead ensured that there were always few, if any, loopholes in his games. In the following game, watch as Iron Tigran utilizes the various positional features at his disposal to slowly crush his opponent.

Petrosian, Tigran vs Unzicker, Wolfgang
Hamburg 1960


1. d4 Nf6
2. Nf3 e6
3. Bg5 d5
4. c4 c6
5. Qc2 Be7
6. e3 O-O
7. Nc3 h6
8. Bf4 Nbd7
9. cxd5 cxd5? (D)


This mistake only serves to cede the open file to White's major pieces. Better would have been 9... exd5 or 9... Nxd5 10. Nxd5 exd5

10. Bd3 a6
11. O-O b5
12. a4 b4

After 12... bxa4 13. Nxa4 Black will have to worry about his weak pawn on a6 as well as the open c and b files.

13. Na2

White does some maneuvering to get his knight onto the b3 square via c1. While the same result could also be achieved by 13. Ne2, Petrosian prefers to keep the e2 square free in case of ...Rc8, in which the queen can escape to e2 and threaten Bxa6.

13... Nb8
14. Nc1 a5

Black wants to prevent his b4 pawn from being cut off by 15. a5, which would turn both a6 and b4 pawns into targets of attack. But now he also pays the price-- the a5 pawn has become a target for the white knight when it lands on b3.

15. Nb3 (D)


Black hopes that one day he will play ...Rc8 to contest for control of the c-file, but he also has to worry about stripping defenders off his vulnerable a5 pawn.

15... Ba6
16. Bxa6 Rxa6

Black has now achieved a positional advantage of sorts-- he has managed to trade off his bad light-squared bishop. However, this also comes at the cost of ceding control of the light squares to the White Queen.

17. Qd3 Ra7
18. Rfc1 Nd6 (D)


19. Bxd6!

A sound positional move-- Black was threatening to obstruct the c-file with 19... Nc4!. White thus trades off his bishop to retain control of the file.

19... Bxd6
20. Rc6! Nb8
21. Rc2 Nd7

With his 20th move White provoked Black to play 20... Nb8 and waste a move. Now White has gained enough time to double his rooks on the c-file.

21... Nd7
22. Rac1 Nb6
23. Qb5

Defending a4 and attacking a5 at the same time. By exploiting Black's weak a and b pawns, White gradually gains dominance of the c-file.

23... Nc4
24. Nfd2

Removing the last defender of the c-file.

24... Nxd2
25. Rxd2 Qa8
26. Rdc2 Rd8
27. Rc6 g6 (D)


There we go. White has achieved full dominance of the c-file... but now what?

On first glance it seems that Black's queenside looks impenetrable, despite White's control of the c-file. The bishop on d6 guards against an invasion of the seventh rank, while the a5 and b6 pawns-- former targets of attack-- are now soundly protected. Does this mean that White has wrestled control of the c-file for nothing at all?

But you may have forgotten one thing: Petrosian is a master of strategy. While most amateurs like us tend to just focus on the main area of battle, a master instead looks over the entire chessboard to ensure that no stone is left unturned. And as he looks over on both wings, he notices something interesting: That the dominance of the c-file seems to not just be concentrated on the queenside, but its power is also transmitted to the other side of the board.

Simply put, White's advantages on the queenside ensures that the white king can cross over to the other wing safely. Once the king has consolidated itself within the queenside, the kingside pawns can then be advanced to strike against the enemy king's position.

And thus Petrosian decides on a "grand" plan: Cross his king over to the queenside, before advancing his pawns to attack kingside. Once this is done, the superior mobility of the white pieces will then ensure that they can swiftly rush over to participate in the assault, while the defending black pieces will have no time to regroup for a fight along a second front.

28. g3 Kg7
29. Kf1

The White king begins its long journey. However, he is guaranteed a safe passage due to the control of the c-file.

29... Kg8
30. h4 h5
31. R1c2


The king will cross behind the rook (via c1) rather than in front, so as to prevent Black from exchanging off a rook with ...Rc8

31... Kh7
32. Ke1 Kg8
33. Kd1 Kh7
34. Kc1 Kg8
35. Kb1 Kh7 (D)


Stage 1 of the plan is complete: The white king is safely tucked away on the queenside. Now Petrosian begins Stage 2: Turning the main theatre of operations onto the kingside.

36. Qe2 Qb7
37. Rc1 Kg7
38. Qb5

Back again. If now Black continues 38... Qxb5? 39. axb5 the passed pawn should prove decisive. As usual, Petrosian is taking his time-- rather than launching his kingside attack straightaway, he decides to play a game of cat-and-mouse with his opponent. Black has chances to make many mistakes now: He may fumble and attempt to simplify the game with 38... Qxb5?, or panic about the impending g4 advance and play the rash 38... f5, weakening his position. It is through these that Iron Tigran slowly squeezes the energy out of his opponents, by repeating his moves and giving the enemy as much opportunity to go wrong as possible.

38... Qa8
39. f4 Kh7

And at last the kingside attack begins. Black continues to wait as the immediate 39... f5 only serves to weaken his position.

40. Qe2 Qb7
41. g4 hxg4
42. Qxg4 Qe7
43. h5 Qf6
44. Ka2 Kg7
45. hxg6 Qxg6
46. Qh4 Be7
47. Qf2 (D)


Note the superior mobility of the White pieces which we have discussed earlier on. White now threatens 48. Rg1 winning the queen.

47... Kf8
48. Nd2 Rb7
49. Nb3


Cautious as always: If 49. Nf3?? then 49... b3+! followed by 50... Rb4 cedes the advantage to Black.

49... Ra7
50. Qh2 Bf6
51. Rc8! (D)


The breakthrough does indeed occur on the c-file, but it is due to White's pressure on the kingside that has made it possible by driving the Black king into the centre. Now, if 51... Rxc8, then 52. Rxc8+ Ke7 53. f5 Qxf5 54. Qb8 is decisive.

52. Nc5 b3+
53. Kxb3 Rd6
54. f5!

With the double threat of 55. fxg6 and 55. Qxd6+

54... Rb6+
55. Ka2 (D)
1-0

Final position after 55. Ka2

Black crumbles under the strong pressure: There is no defence to be found against the double threat of fxg6 and Nd7+. This is certainly a brilliant game where Iron Tigran shows his mastery over all sorts of positional and strategic devices.

In our next part, we will examine more games from Petrosian.

Links:
Part 1: http://nushsblackknights.blogspot.com/2013/09/the-story-of-iron-tigran-part-1.html

Sources:
"The Giants of Strategy" by Neil Mcdonald

Thursday, October 3, 2013

The art of successful defense: Part 4

In the process of defending one should also strive for active defense-- that is, creating new threats against the attacker in the process of defending. In this way the attacker will be given the additional burden of having to meet with these new threats should his attack fail, such that he does not have the time to regroup his forces and launch a second attack.

And thus, I introduce the final topic of this series that covers the broad aspect of active defense:

Defense by counterattack

You've just beaten off an enemy assault. But you are not content with a draw; you want a win. Plus, your opponent still has considerable strength and is threatening to renew his offensive. You don't want to go through the hassle of having to defend a second time... so you strike him first!

We start simple:

Checkerboard 5 vs Checkerboard 6
Black Knights Internal Tournament 2013 (Modified)
White to move

In the above position, White has managed to utilize a blockade of the h-pawns to slow down Black's attack...for now. However, Black still has considerable forces which he can use to organize a second offensive along the kingside-- for example, by grouping his major pieces along the f and g files before breaking into the position with a possible knight sac on g3.

White thus sees that he has to deny Black of the time needed to regroup his pieces. To do this, he must create threats of his own on the opposite wing...

1. a5

And now Black suddenly finds that he has to contend with the threats towards his queenside castled position! The threat of 2. Bc6 followed by a breaking through of the b-file forces Black to postpone his attack in order to meet with White's counterattack.

...

When deciding whether to employ a direct, prophylactic defence or to launch a counterattack, one should first take a look at the nature of the position, mainly the scale of the attacker's commitment to his assault. Launching a counterattack too late may not give the defender enough time to save the game, while launching it too early may lead to the potential of backfiring.

The following game is a good illustration to the relationship between the scale of the attacker's commitment, and the method of defence employed:

Source Unknown
Position after 1. Re3

With his last move White intends to lift the rook onto g3 or h3 for an attack along the kingside. However, such rook sorties do not indicate serious commitment for the attacker; at this stage, the rook can still retreat to the 1st rank if the attack does not succeed.

Black has an open c-file at his disposal which he can use to launch a counterattack-- however, White is not yet fully committed to the assault, so he can quickly retreat his troops to organize an effective defence should the counterattack arise. Hence, Black decides that the conditions are not yet favourable for a counter-thrust, and decides to employ a passive prophylactic defence for now.

1... c6 2. Rg3 Kh8

A prophylactic move against 3. Bh6

3. Be3 Be4

By exchanging light-squared bishops, Black hopes to slow down White's attack and at the same time clear the squares on the c-file for a counterattack later on.

4. Rh3 Qd5 5. f3!?

White makes a dangerous commitment to his plans-- if the attack fails, White's rook will be unable to retreat without significant loss in tempo.

5... Bxd3 6. Qxd3 (D)


6... Bd6?

Up till now Black had been cautious in employing a passive defence against White's threats, at the same time keeping his trump cards (the c-file and the d5 outpost) in reserve. Now, however, he wrongly decides that the time is ripe for a counterattack and makes a careless move. All White now has to do will be to play 7. Bg5! and Black has to give up a piece to avoid being mated on h7. But fortunately for Black...

7. Bf4?

And White throws away his chances of achieving a quick victory! After this text move, Black reasserts his advantage and continues on with his plans:

7...g6 8. g4

Black was threatening 8... Nh5. With his last move White has already committed himself fully to the offensive; but Black now seizes the chance and his counterattack grows in strength:

10. Bg5 Bxe5 11. dxe5 Ng8 12. Rg3 (D)


White finally admits that his attack is not successful, and makes some attempt to defend against Black's threats on the second rank. If 12. Bf6+ then 12... Nxf6 13. exf6 Qc5 and Black stands better.

12... Rc2 13. Rg2 Rxg2+ 14. Kxg2 Rc2+ 15. Kg3 Kg7! 16. Bf4 h6 17. h4 h5! 18. gxh5

Otherwise Black will open up the kingside with 18... hxg5

18... Ne7 19. Qb3

19. h6+ is tempting, but will not work because of 19... Kh7

19... Nf5+ 20. Kg4 Rc4 21. Re1 (D)


There is no apparent defence to Black's counterattack now. If 21. Rd1, then White loses even faster after 21... Qxd1! 22. Qxd1 Ne3+

21... Rxf4+ 22. Kxf4 Qd4+ 23. Re4 Qf2 24. Kg5 Qd2+ 25. Rf4 Qd8+ 26. Kg4 Qxh4# 0-1

Position after 26... Qxh4#

As quoted by Vladimir Vuković: "If one leaves aside Black's unpunished mistake on the sixth move, then the whole course of the game is a good illustration of the relationship between the scale of the attacker's commitment and the method of defence employed. In the first phase White is not heavily committed by his rook's excursion and Black carries out a cautious direct defense without compromising his king position. He also maintains his hold on the c-file and the centre and eliminates one enemy unit-- the light-squared bishop."

"With f3 and g4 White has already taken on greater obligations and so the time is ripe for indirect defence by means of an action along the c-file. As soon as another unit is eliminated (the knight on e5) it is all over with White's attack, whereas the counterattack grows from move to move, with the lack of communication between the white rooks as the main cause of White's misfortune."


And with that, I close my series of articles on the art of successful defence. I hope this has helped you in better understanding and perfecting the various defensive techniques which you will encounter in tournament play.

Links:
Part 1: http://nushsblackknights.blogspot.com/2013/08/the-art-of-successful-defence-part-1.html
Part 2: http://nushsblackknights.blogspot.com/2013/09/the-art-of-successful-defence-part-2.html
Part 3: http://nushsblackknights.blogspot.com/2013/09/the-art-of-successful-defense-part-3.html

Sources:
"Art of Attack in Chess" by Vladimir Vuković