Sunday, April 29, 2007

Endgame tactics 2


Last time I showed a rook ending in which a tactical device simplified the task of converting an extra pawn. Today there is a similar example on the menu.

The position in the diagram arose in one of my games from the 1976 B.C. Championship. After an unusual opening a weak pawn had appeared on e4, and in the middlegame that followed I managed to exchange off every piece that could reasonably defend it. We have now arrived in a rook ending with the pawn about to be captured.

34.Rxe4 Kd6 35.Ke3 Rf7
No better is 35...Rb5 36.f4 h5 37.Kd3 g6 38.Ke3 and Black is in a mini-zugzwang; for example, 38...Rd5 39.Rd4 or 38...Kd7 39.Re5.
36.Rd4+!?
Of course the natural move here is 36.f4, so my actual move 36.Rd4+ requires a bit of explanation. After 35...Rf7 it didn't take me too long to work out my opponent's defensive strategy, which in simple terms consists in defending the b-pawn laterally with his rook and keeping his king centralised in order to prevent the advance of White's king. With these thoughts in mind I worked out a few variations and in so doing spotted an unusual tactical trick.
36...Ke5
As predicted!
37.f4+ Kf5 38.g4+!
This appeared to take Black by surprise.
38...Kxg4 39.f5+! Kxf5
This loses immediately, but after 39...Kh5 40.fxe6 Re7 41.Re4 Black cannot hold the position; for example, 41...g5 42.hxg5 Kxg5 43.Kd4 Kf6 44.Kd5, etc.
40.Rf4+ Kg6 41.h5+!
The main point of White's play. Black's king is deflected away from his rook, which is then captured by White for an easy win.
1-0

Being able to foresee and make use of tactical devices in order to simplify the task of converting an advantage is part of what is known collectively as endgame technique. It is very important that in playing for such tricks we analyse carefully and do not allow the opponent any surprise defences that may bring him back into the game. For example, in this game it was very important that the alternative 39...Kh5 did not bring any relief to Black.

Monday, April 23, 2007

Endgame tactics



Picture this: after a difficult middlegame you have managed to transpose into an endgame with an extra outside passed pawn. Smooth sailing, right? No, not always. If your opponent has blockaded your extra pawn you could still have a lot of work left to do. Before casting around for a second target, it is often worth another look to see if the blockade is actually all that sturdy.

Here is an example from one of my games in the 1983 B.C. Open. I am Black and I would like to promote my advanced b-pawn, but there doesn't seem to be an easy way forward at the moment. Enter the tactician... it turns out that the geometrical situation is perfect for an unusual trick:
1...Qc4
Attacking the f-pawn. If White lets it go his position will deteriorate rapidly.
2.Rf3 Qc2+!
White's reply is more-or-less forced because the alternative 2.Rf2 runs into 2...Qxf2+! 3.Qxf2 b2 and Black will either win White's queen or get a new one of his own.
3.Qxc2 bxc2 4.Rc3
My opponent had banged out his last two moves quickly and was now looking quite satisfied with himself. Unfortunately for him, I have seen a bit further:
4...Rb2!
Although this is not a check, it has similar force. I am threatening the discovery 5...c1Q+, to which 5.Kg1 is no defence because of 5...Rb1+ followed by 6...c1Q and wins. So my opponent grabbed his king and went to play it up a rank... and then froze in mid-move... and then turned somewhat red... With his time running down he eventually realised he had to move the king that was in his hand, so he quietly put it on g3, pressed the clock, and waited...
5.Kg3 Rb3!
The point of Black's manoeuvre. White's rook is now pinned against his king and he has lost control of the important c-file. My opponent did not want to see any more and resigned the game here.

Saturday, April 21, 2007

Duplication


One of the oddities of chess is that it is entirely possible to give a good effort, win an interesting game... and then find out that it has all been played before. This is pretty much what happened to me this morning, in an Internet blitz game against a player whose rating was very close to my own. When a tactical opportunity presented itself I had to think for a minute before responding but it was time well spent because the game was soon over.

I have the White pieces.
1.d4 d5 2.c4 Nc6 3.Nf3 Nf6?!
Stronger is the main line move 3...Bg4.
4.cxd5 Nxd5 5.e4 Nf6 6.Nc3 Bg4 7.d5
Black has already gone wrong and here he should try to dig in with 7...Bxf3 8.gxf3 Ne5. But White keeps an advantage with 9.f4 Ned7 10.e5 Ng8 and now 11.Qb3 seems best. Instead of this Black plays a tempting but unsound move whose only merit is increasing the pressure on f3.
7...Ne5? (diagram)
White to play and win!
8.Nxe5! Bxd1 9.Bb5+ c6 10.dxc6
White now threatens both 11.cxb7+ and 11.c7+ followed by liquidation on d7 and a recapture on d1. Black has a whole tempo to work with but cannot prevent the loss of at least a piece.
10...bxc6
This loses quickly. The alternatives are:
a) 10...a6 11.c7+ axb5 12.cxd8Q+ Rxd8 13.Nxd1 with an extra piece for White;
b) 10...Bg4 and now:
i) 11.c7+?! Qd7! (stronger than 11...Bd7?! 12.cxd8+ Rxd8 13.Nxd7 Nxd7 14.0-0 e6 15.Rd1 Be7 16.Bf4 a6 17.Ba4 b5 18.Nxb5! axb5 19.Bxb5 f6 20.Rxd7 Rxd7 21.Rd1 and Black resigned in Zimlich-Baumgardt, German League 1996/97) 12.Nxd7 Bxd7 13.Bf4. Here White is only a pawn up but should still win eventually;
ii) 11.cxb7+ Bd7 12.Nxd7 Nxd7 13.bxa8Q Qxa8 14.0-0 and Black cannot prevent 15.Rd1, which will leave White with three pieces against Black's queen;
iii) 11.Nxg4! bxc6 12.Bxc6+ Nd7 13.Ne5 e6 14.Bxd7+ and White finishes a piece ahead after either 14...Qxd7 or 14...Ke7 15.Nc6+.
11.Bxc6+ Nd7 12.Bxd7+ Qxd7 13.Nxd7 Kxd7 14.Nxd1
Black resigned.
1-0

Wednesday, April 18, 2007

Zwischenkombination





One of my tournament games from a few years ago featured a positional sacrifice of two minor pieces for a rook and two pawns. Working with the added advantage of more active pieces I managed to grind down my opponent and score a fairly convincing victory.

While analysing the game later on I found a much nicer continuation that had completely escaped my notice during play. I don't quite know how to characterise it, so I've taken advantage of that wonderful convention of the German language and coined the term zwischenkombination. Experienced chess readers will no doubt grasp the intended meaning: an in-between combination; or in other words, a combination in the middle of another combination.

In the first diagram I am playing Black and my last move was the liberating 23...c5! My opponent's position is now somewhat worse but probably defensible with best play. Happily for me he makes a mistake.
24.Nb1?
Before executing a move it can be useful to ask oneself how it changes the position. Decentralising moves are especially risky because they tend to leave key squares undefended. Black takes immediate advantage.
24...Bxe4! 25.fxe4 Nxe4 26.Qe1 (second diagram)
Black's next move regains material and is thematic, obvious, and... not the best!
26...Nxd2?!
Have a look at the intermediate combination that starts with the move 26...Nxc2!! It turns out White is in a very bad way no matter what he does; for example: 27.Rxd7 Rxd7 (not 27...Nxe1? 28.Rxc7 Rxd1 29.Rxe7 Rxb1 30.Nxc5 and White is actually better) 28.Rxd7 Qxd7 29.Qc1 Ng3+! (and not 29...Nxe3 30.Qxe3 Qd1 31.N1d2 with some defensive chances) 30.Kg1 Nxf1. With this move Black regains the piece and remains at least two pawns up. In missing this possibility I did not perceive that eliminating White's c-pawn would leave his knights undefended, in particular the one on b3.
After 26...Nxd2 the game continued:
27.Rxd2 Nf5 28.Qf2?!
Of course White should not surrender his dark-squared bishop so readily. I had analysed 28.Bf2 c4 29.Rxd7 Qxd7 30.N3d2 Bg5 31.Ne4 Qd1 and assessed it as better for Black, which seems fairly accurate.
28...Nxe3 29.Qxe3 c4 30.Rxd7 Rxd7 31.N3d2
And now for some reason I rejected 31...f5! 32.Nf3 e4 33.Nd4 Bc5 34.c3 but of course in this variation 34...Qe5! is easily winning for Black. Instead I played 31...Bc5?! but still won after a further 20 moves. Chess is a difficult game.

Wednesday, April 11, 2007

Quo vadis


During a break at the recently-concluded Grand Pacific Open in Victoria I happened to be in the hotel lobby watching a blitz game between two juniors. When the diagrammed position was reached both players commented that they had no idea how the play should continue or who, if anyone, was winning.

Does Black have the advantage because his rook is supporting an outside passed pawn from behind and tying up White's rook in the process? Or does White have the advantage because of his pawn duo and the opportunity to advance it and perhaps attack Black's king?

It is one of the paradoxes of chess that the fewer pieces remain on the board, the more difficult the game becomes for human players. A major reason is that many endgame positions cannot be assessed properly without a deep and accurate calculation of variations. When faced with a board consisting largely of empty space it can actually be difficult to keep track of where the pieces are, to say nothing of where they should be going or what they can accomplish.

From the practical side there is just no substitute for extended analytical work on as wide a variety of endgame positions as possible. Without absorbing the general principles and technical devices that apply to the endgame a player will never achieve even average proficiency in this phase of the game. Based on my own difficult experience I always advise players of all ages and playing strengths to dedicate a part of their chess experience to a study of the endgame.

Let's clear up the mystery of the diagrammed position: White is winning very easily. Yes, his rook is tied up. But if the blockade is lifted, Black's pawn will not queen for at least four more moves. In the meantime by combining the action of his forces White can carry out an enveloping manoeuvre against Black's king.

Here is how the game might continue:
1.g5 Kf7 2.h5 Kg7 3.Kg4 Kf7 4.Kf5 Kg7 5.h6+ Kh7 6.Kg4! Kg6
It looks as if Black has managed to blockade White's pawns, but here is where White's rook enters the picture.
7.Rd4! Kf7
If 7...b4 then 8.Rd7! and Black's king is caught in a mating net.
8.Kf5 Kg8 9.Rd7 Rf8+ 10.Kg6 Rb8 11.h7+ Kh8 12.Kh6 b4 13.g6
Black is faced with the threat of mate by 14.g7, and 13...Rb6 is no defence because of 14.Rd8 mate.

Thursday, April 5, 2007

Impetuosity






One of my very favourite chess servers is Playchess.com. In order to join Playchess you must own ChessBase or one of its related playing programs such as Fritz, Shredder or Junior. Because of this prerequisite there are always strong players logged in and not surprisingly they are from all over the world.

As far as I know, ratings are calculated using the Glicko system. This system does not correspond exactly with the Elo system but is thought by its developer to be more accurate in terms of ranking and expected results.

Anyone who has played much anonymous speed chess knows that when you encounter a wide range of players you will eventually get an opportunity to win a miniature game with a combination straight out of Chernev or Reinfeld. Yesterday I got such an opportunity.

I am White in the first diagrammed position, which arose after the moves 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 d6 5.c4 Nf6 6.Nc3 Nxd4 7.Qxd4 Bd7 8.Be2 Bc6 9.0-0 Qc7?! Black's last move was not the best one. The reply was 10.Nd5! putting the question to the queen, to which my opponent replied 10...Bxd5 11.cxd5 Qc5?

Chasing after exchanges is a classic psychological failing. Here the consequences are immediate after White's next move 12.Qa4+!, which is very difficult for Black to meet. Moving his king is obviously out of the question, so he is forced to interpose with 12...Nd7. White now follows up with 13.Be3 Qc7 14.Rac1 Qd8, leading to the second diagram.

Black has lost so much time with his queen that White is already winning by force. Two unusual bishop moves do the trick: 15.Bg4! g6 16.Bb6!

Because of the mate on d7 it is obvious that 16...axb6 is the only move to save Black's queen. But with the rook on a8 now under attack White is able to conclude matters with 17.Bxd7+ Qxd7 18.Qxa8+.

Black was forced to resign here. After 18...Qd8 White has a pleasant choice between the simple 19.Rc8 and the more accurate 19.Qa4+ b5 20.Qxb5+ Qd7 21.Rc8 mate.

Tuesday, April 3, 2007

Crystal ball


It is generally accepted that the Sicilian Defence did not fully enter the modern era until the early 1950s due mainly to the efforts of Soviet players such as Vsevolod Rauser, Isaak Boleslavsky and David Bronstein.

In this connection many of the theoretical recommendations made before the Second World War look exceedingly quaint from today's perspective. For example, after the moves 1.e4 c5 2.Nf3 Nc6 no less a figure than Alexander Alekhine came down strongly in favour of 3.Be2, considering it to be clearly White's best move. If such a dynamic player as Alekhine could be so dogmatic, what then of Dr Siegbert Tarrasch, a classical player whose stubbornness was the stuff of legend?

The position in the diagram comes about after the moves 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 e5 6.Ndb5. In the game Tarrasch-Mieses, Nuremburg 1888, Black now played 6...a6?!, provoking the following prophetic annotation from Praeceptor Germaniae:

“I would play ...d7-d6 here in order to retain the dark-squared bishop, which is needed for the defence of Black's weaknesses. This move also has the advantage that White's knight would be forced into a poor position for some time: 6...d6 7.Bg5 a6 8.Bxf6 gxf6 9.Na3 b5 10.Nd5 f5. Although White has a noticeable advantage here (based primarily on his control of the square d5) Black's chances would have been better than in the game thanks in large part to his much faster development.”

The variation cited above is of course known today as the Sveshnikov Variation, which made its modern appearance in the mid-1960s. Yet Dr Tarrasch wrote this note while preparing his book Dreihundert Schachpartien... in 1895!

About Me

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Port Coquitlam, British Columbia, Canada
National master (Canada) since 1984. B.C. Champion 1977 and 1984. Runner-up 1991 and 2002. B.C. Open Champion 1972 and 1982. B.C. U/14 Champion 1964-65-66. Mikhail Botvinnik once wrote that publishing your analytical work forces you to be accurate because it exposes you to criticism. Hence this blog.