Showing posts with label Mistakes. Show all posts
Showing posts with label Mistakes. Show all posts

Wednesday, 10 December 2008

Never miss a second opportunity

There are some situations in chess where you have time to set something up and get it just right, and some where you have to act quickly to take advantage of a temporary situation. One of the commonest sorts of chess mistake consists of thinking a situation is of one type when it is of the other. In the featured game here, black makes a mistake of this type, but is lucky enough to get a chance to put it right.

The position above arose in the game Dooley-Oughton. Rob Oughton, black to play here, can make a good central pawn break here with 12...d5, exploiting the inability of the e-pawn to capture it without allowing a fork. This will then give him the opportunity later to decide the central pawn situation in his favour: either he creates a protected passed pawn with ...d4, or he plays ...dxe4 to give himself a mobile pawn majority on the kingside.

Instead, Rob thought he had all the time in the world to make the central pawn break and played 12...Bb7?!, setting up extra protection for the d-pawn when it does go to d5. Play continued 13.Re1 Re8 (he can't now play ...d5 because the e-pawn would hang), reaching the position on the right here:

Now white played 14.Bd2?, and black got the second opportunity he'd been waiting for, and played 14...d5, giving him the advantage. He went on to reach a winning position a few moves later.

But there was a way to make things much more difficult for black: 14.c5! cripples the pawn break before it starts. This way, 14...d5 would be harmless because white could just play 15.cxd6, and the positional factors would be slightly in white's favour - the c6 pawn would be isolated and weak. In fact, it's not easy to find a constructive plan for black after 14.c5, simply because so much of his piece placement is devoted to getting ...d5 in.

Indeed, this is a common theme in the opening black chose; in many lines of the Benoni, white snuffs out a potential black pawn roller with a timely a4-a5 advance to make ...b5 impossible without allowing an en passant capture. A common way for black to stop this is to play ...b6 before the pawn reaches a5, thus ensuring that the en passant capture never takes place. The same idea could have happened here as well, with ...d6 on move 12 or 13, which would alter the dynamics of a c5 advance from white.

Monday, 17 November 2008

Visual Errors

This position appeared in tonight's club championship game between Jon Munsey and Richard Smith. White is two pawns up, but has been under heavy pressure for most of the game.

Now black could have maintained this heavy pressure with 26...f3 27.gxf3 Bxf3, with the possibility of 28...Re8 in the offing. This would have given him quite substantial compensation for his sacrificed material.

Instead, he thought he could finish the game off immediately, and played 26...Re3+??. This proved in the game to be the right decision, as white blundered in response with 27.Kf2, allowing 27...Re2#. However, the right response was the simple 27.dxe3, after which Richard's planned 27...Rd1+ 28.Kf2 Bxe3+ has one small flaw: it isn't mate. 29.Bxe3 leaves white a rook up with a winning position.

Why did Richard overlook this? It was probably a "visual error", one caused by not actually seeing how the pieces are going to be moving. The bishop on c1 isn't capable of moving to e3 in the diagram position, so it's harder to see that it will be able to do so when the d-pawn moves away. In addition to that, it's been useless and motionless for so long that it's hard to think of its playing a vital part in the game.

Sunday, 16 November 2008

Blind Spots and Beamed Headlights

I have a love/hate relationship with county matches. The "hate" part is all about the travelling I'm required to do for them; any county match further from home than Taunton requires leaving Bideford at 08:30 and getting back at 00:10 the following day. Of course, part of this is because I play for a county in which I no longer live, but, given how much North Devon is represented in the county team, playing for Devon probably wouldn't help much.

The "love" part is all about the matches themselves. Meeting all my old friends from the Somerset League, getting practice playing serious games against tough opposition without its having an immediate effect on my FIDE rating, and on this occasion, winning 11-5 against Hampshire. Nowadays that's not such an amazing result, but when I first started playing for Somerset in 1987, Hampshire were by far the strongest team in the region, and beating them still gives a sense of achievement. (It's a little as if one's national football team beats Uruguay.)

In this particular county match, I also got the opportunity to notice some weaknesses in my own play; this is not something into which I usually have great insight, so I'm pleased when it happens. Take the following two positions:


This is the position after I played 20...Bd5, after which my opponent played 21.c4, attacking my bishop. A natural enough move, but I'd completely missed it. And the reason I'd missed it was that I have a blind spot in my play - I habitually overlook moves that allow en passant captures, even if the capture is not any good. (I had considered 21.c3 and was not going to capture on c3 had Yeo played it, so it certainly wasn't a case of rejecting the move based on how I would have responded to 21.c3.) As it happens, the move I'd overlooked probably wasn't the strongest anyway, but on other occasions it might have been.

From the diagram, play then continued 21.c4 Bf7 22.c5 Nxc5 23.Nxc5 Qxc5 24. Rac1 Qd5, and my opponent's next move was the natural and good 25.Bxf5, winning his pawn back.

I had also considered another move for him here, and this was 25.Bc4, attacking my queen. Some thought reveals why this is not a good move: I can play 25...Rxe1+ 26.Qxe1 Qd7, and white isn't getting his pawn back any time soon.

However, my mind had been distracted by another option for black there, and that was the positional queen sacrifice 25...Qxc4. This is probably not as good as the simple line I've just given, but it attracted itself to my consciousness a little like an oncoming car's headlight does when it's set to "beam", and it would take great effort to restrain myself from playing it in the game. This is, I suppose, an inverted blind spot: when an opportunity to create an unusual material balance occurs, I have to make a special effort to notice anything else.

Trying to find blind spots and beamed headlights is not easy, but it's probably something that will pay off for most players looking to improve their game. I hope it's something that will improve mine.


Friday, 14 November 2008

Unreasonable Alternatives

I believe it was Andrew Soltis who said that "most chess players blunder when faced with a choice of two reasonable alternatives". The reasoning is clear: when you've only got one reasonable move you can make, you just play it and, if it loses, you were losing anyway. When, however, you've got more than one, you've got to analyse all of them, and occasionally the process short-circuits, and you pick the wrong one.

The diagram above, taken from today's Mauritus-Seychelles match in the Olympiad, is a good example. Roy Phillips, playing white here, has just played 11.e5 to try to exploit his lead in development. How could his opponent respond?

Well, one obvious choice is to play 11...Nh6, hoping that the king will not come under too much fire if white goes in for 12.exd6 exd6 13.Re1+. The other option is to try to keep the centre closed with 11...d5, hoping that won't weaken the c5 pawn too much.

In the game, Kurt Meier decided that his best option was to keep the centre closed with 11...d5?, but he soon wished he hadn't. The game continued 12.Na4 Rb5 13.c4 Ra5 14.b3 e5 15.Bd2, giving us the position on the right. It is now clear that black will have to give up material, the c5 pawn is still weak, and he has ended up opening a vital file for white's rooks anyway.

Now this line is not very difficult to calculate, in and of itself. It's also not particularly guaranteed by the general nature of the position; had black's e-pawn already been on e6 in the first diagram, his choice of move would have been perfectly fine, because he would have been able to defend the c-pawn with ...Bf8. Which I think explains why the blunder happened: the move played made sense, and would have been the right move in a similar position. It just so happened that the specific features of the actual position were such that the move itself was a losing blunder.