Wednesday, February 27, 2008

A tactical game

Yesterday, as Black in a club championship game, I had lost a pawn in the opening. Or should I say I sacrificed it? No, it was not planned, but it came out that I had quite a compensation for it. Just look at this position after black Rook attacks Bishop and white Queen protects it, move 18.

position 1

Black to move.

I have five developed pieces against his only two. And even more important, his King is still in the center. Thus, I thought that the Knight sacrifice on e4 must be good. Interestingly, Shredder sees me as winning after Nxe4, but my feeling at the board was quite different as soon as I realized that I do not win his Bishop and I am a full piece down. I thought that I was struggling against loss! On the other hand, I had the impression that my opponent had the feeling of winning because he seemed not to be very concerned about the danger of his King. This has been a very important experience, learning more about the power of a compensation.

Despite some weak moves of mine I managed to keep the upper hand and, due to his weak defense, gained material back. And here is the beautiful finish after 32. Bf4.

position 2

Black to move. My final blast makes use of the overworked Queen. I guess you see it.

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Friday, February 15, 2008

Too greedy for material

The thoughtful comments on this position (thanks Christian, Phaedrus and Sciurus) tell me that I should reconsider it. I think this is also worthwhile because Shredder rates it as +2 pawn units with a couple of candidate moves, even without an immediate material win. Only after a depth of 14 half-moves he spots a tactic.

My impression over the board has been in the range of one pawn unit of positional advantage, and I spotted a plan to materialize it.

position

White to move.

The game went as follows: 1. Bf5 Bxf5 2. Qxf5 g6 3. Qd7 Na5 4. Qxc7 and I win a pawn according to my plan. But it has a hole because Black can play Nb3 with counterattack, reducing my advantage to a meek 0.8 pawn units. My opponent played passively 4.-Nc4 covering the pawn, and after 5. exd6 Nxd6 I win another pawn because of the overworked Queen f8.

Now I try to figure out how Shredder may come to its 2 pawn units of positional advantage. My bishop pair accounts for 0.5 pawn units. My center pawn outpost may be worth another 0.5 units. The poor Nh5 gives me at least another 0.5 units, the worse Nc6 and Qf8 may be 0.25 each, so we get a total of 2 pawn units.

A good plan would have been the minority attack a4, as pointed out by Sciurus. Opening the game would have accentuated the superiority of my bishop pair. Actually, I control the center and I have more material power on queenside, thus I should attack there. Very logical.

But I have missed a tactic here. The poor Knight on h5 has no squares and I could fetch it with g4 were not the Bishop on d7. But this Bishop can be overworked with 1. Be4! If now Rad8 to unpin the Knight, 2. g4 gets the piece. Very nice. But Shredder took a while to find it.

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Thursday, February 14, 2008

Trading a bad for a good piece

position

Ten days ago I had a win as White in a club championship match. As you can see, White has a superior position. In spite of equal material, Shredder rates White 2 pawn units better. But it is funny that I did not play one of the moves Shredder rates best here: Be4, a4, Bh7+, c4, and even h3. I simply cannot figure out a sense behind these moves.

What I played is Bf5, offering the piece I considered worst of all my pieces against his best piece, the Bishop d7. My main idea was bringing my Queen into play with various threats against uncovered pieces and pawns. The only drawback is that I lose the advantage of the bishop pair. But this is more than compensated by his loss of best piece. He took on f5, Queen took back, protecting the Knight with g6 was forced, and now my Queen entered his seventh rank, Qd7, forking the unprotected Knight and the pawn. After that, my game was won.

The interesting point here is how differently humans and computers look at a position. Shredder did not even consider Bf5, yet I am convinced that this was my best move because it is part of a clear plan.

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Wednesday, February 13, 2008

A stupid loss of tempo

Yesterday I played as White against my old friend Martin. I came better out of the opening but my positional advantage was only minimal when we came to this position after the eleventh move of Black.

position

White to move.

My small advantage is a faster connection of the Rooks and better prospects of taking the e file, hoping to invade the seventh rank. Going for this plan, I should have played 12. Re1 or 12. Bxg5. I rejected the latter because I did not want to give his Queen a tempo.

I played 12. Be3 with the vague idea of taking back with the pawn, opening a battery on f7. But after he took the Bishop I came to the conclusion that this attack can easily be parried, leaving me with a wrecked pawn structure. So I took with the Queen, he attacked the Queen and I lost one more tempo. The advantage has gone, and after another twelve moves the game was drawn.

Somehow I was not able to keep books of the tempi. His Bishop g5 has used 2 tempi so far, mine at c1 has used none. Whether I wait for the Bishop being taken or take myself on g5 does not matter, I always gain tempo. The only thing to avoid is giving a tempo by moving the Bishop on e3 or f4. Which I did, unfortunately.

After Bxc1 Rxc1 my Rook has lost a tempo because it will not remain there, but this loss is fully compensated by the tempo loss of the black Bishop.

A second fault in this position was not ruling out the attack battery plan on f7 at once. If this plan is not feasible, then Be3 has no purpose at all.

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