The Chess Mind

Just as with Karpov's 2.5-1.5 rapid chess victory over Kasparov in 2002, Spassky's victory over Karpov in a 15+5 (15 minutes per side for the game, with 5 second increments after each move) match this past Friday (May 26) in Corsica was objectively meaningless but surely emotionally fulfilling, as the winner in each case obtained a minute quantity of revenge for earlier, far more significant, defeats.

So congratulations to Spassky, whose win (with some comments on the endgame) can be found here. Once upon a time, chess writers wrote about having a queenside majority as if it automatically conferred a significant edge on its possessor. The thinking was that it would generate an outside passed pawn, and while the weaker side was blockading it, the stronger side would head for the opponent's kingside pawns at a timely moment.

Nowadays, the queenside majority mantra has been rejected; if anything, most players prefer the opposing majority - generally 4 on 3 on the kingside with the extra pawn on the e-file. The reason: that majority will sometimes provide its possessor a significant spatial advantage in the center.

In this game, however, the old model held sway with apparent textbook precision, but in truth it took three errors before Black was clearly lost. It's an instructive ending deserving study, and I hope you'll all take advantage of it: if Karpov had something to learn here, surely we do, too!

Yesterday's flurry of posts included an endgame exercise: take the following position (discovered [invented, if you're not a Platonist of any sort] by Brian Karen), with White to move, and prove a win.



White's bishop is much better than Black's knight, but there are various complicating factors. The first is that his a-pawn is in trouble, the second is that he's a pawn down, and the third is the specter of a bishop + wrong-colored rook pawn ending - if the Black king can reach h8 and the knight grab the a-pawn, Black can lose all his guys and still draw.

Try to work it out first, and when you're ready to see the solution, click here.

Here's a position created by Brian Karen as an exercise for his students: White to move and win.



It's not particularly artistic, so if you try to solve it like a study, searching for some brilliant idea, you'll frustrate yourself. It is a reasonably challenging exercise, however; in fact, while Brian intended it to be relatively easy, he found to his surprise that it was rather difficult - even for him!

Solution to be given later.

A few weeks ago I offered the endgame of Fedorchuk-Simonenko as an exercise to my readers. White won, but the position was drawn for a long time before Black finally went astray. The task, for those who chose to accept it, was to figure out where Black lost the game, and - after an overly long, if understandable delay - the details can be found here.

[Congrats to Chris Falter, who not only solved the puzzle but also found an elegant defensive idea for Black a few moves earlier that would have made the draw even simpler.]

Al Steiner writes in to ask about this position:

Dennis,

Bishops of opposite color, 1 extra pawn for black, white to move and….. draw? A few of us at chessbase tried to work this out, and cannot find a win for white OR a draw. Black always seems to get the black bishop and then the win. What do you think?

...If it is truly an odd position, where opposite color bishops don’t draw, then I thought you might be able to use it on “The Chess Mind”. If not, then just chuck it in the recycle bin. Yes, it is my game. I couldn’t find a draw with fritz, and neither could a friend with rybka. Then again, I’m no fritz expert.

We played with it for a while, and it seems the h pawn keeps white’s king on the kingside, and therefore white cannot prevent the outside passed pawn with out giving up his bishop.

Thanks for writing, Al: your letter affords the opportunity to remind the readers of at least three very important points. First, nowhere near all opposite-colored bishop endings are drawn; second, a handy rule of thumb for evaluating whether an ending is a win or a draw is the so-called principle of two weaknesses; third, beware of the glib generalizations of beginners' books. We'll take each point in turn, but first let me offer the bottom line about this position: It's a straightforward win for Black, as the passed h-pawn and pending passed a-pawn stretch White's defenses beyond what they can bear.

(1) Opposite-colored bishop endings

Opposite-colored bishop endings do have a higher drawing ratio than other endings, for two reasons. First, it's often possible for the weaker side to arrange the pawns so they're immune to attack. If the strong side has a light-squared bishop and all the pawns are on dark squares, protected by (a) other pawns, (b) the bishop, and/or (c) the king, then that's the end of that, unless the strong side also has a passed pawn to bother the opponent. Second, when there is a passed pawn, the weaker side can often blockade it on a square whose color is the same as its bishop and opposite that of the opponent's.

(2) The principle of two weaknesses

That's the good news for the defender. The bad news is that there are plenty of exceptions, and the position above is one of them. And here we can combine our first and second main points: not all opposite-colored bishops are drawn, and we can identify that this is likely one of those exceptions on account of White's two "weaknesses".

Let's parse this statement - what does it mean? All of White's pawns are defended and will be safe practically forever, so where are the weaknesses? The answer is that "weakness" is used in an extended sense; here it refers, roughly, to anything a player needs to defend or defend against: a pawn, a square, the king, a queening threat, etc. And White has to defend against two big threats: the h-pawn and the a-pawn. If it was only one or the other, then White could draw in his sleep, but the two together leave him in a hopeless situation. (For some analytical confirmation, click here.)

(3) Rules of thumb

I close with a reminder. Basic books offering rules of thumb are quite useful to beginners, helping reduce the buzzing blooming confusion of the chess board to something more manageable. The sober truth, however, is that the game is very concrete, and exceptions abound. Opposite-colored bishop endings can be won and lost, and in the middle game they often favor the attacking side. It's often fine to move pieces more than once in the opening (think of White's Ng1-f3xd4-b5-a3-c2-e3 in the Sveshnikov Sicilian), to bring the queen out early, to grab "poisoned" pawns, and so on.

These rules of thumb are only tools, not immutable laws. As such, they are our servants, not our masters, and if a tool doesn't help for the job at hand, we should change tools, not jobs!

The game Fedorchuk-Simonenko from the Dubai Open saw Black suffer a long, long time in a drawn ending before finally going astray and losing. But where did he go wrong? Start on move 77 and go forward (or start from the end and work your backward) and see what you can find. (But don't use your chess engines - they'll give you the right answer immediately!) It's good practice, a bit of a challenge (otherwise Simonenko wouldn't have gone astray), but not too difficult for a player with some background knowledge to figure out.

The game is here. The solution will be given in a few days; please do not comment your answers.