The Chess Mind

From our opposite-colored bishop ending series we return to one on bishops of the same color, albeit in a situation that has so far quickly resolved into a pure pawn ending. This was our starting position, with Black to move:



The first line for your investigation was given here, while in part two the variation was modified. There an assignment was given: after the moves 1...Bd6 2.h3 Bc7 3.Kb3 Bxa5 4.Bxa5 Kxa5 5.Kc4 Kb6 6.Kd5 Kc7 7.Ke5 Kd7 8.Kxf5 Ke7 White is winning, but it's not at all easy to see how.



When you think you've got it, you can have a look here. In a day or two, we'll turn to part four, in which we clean up some odds and ends, and then discuss whether we can turn this ending into a worthwhile study. There are at least a couple of study composers in my audience, so I'm hopeful!

It has been, shall we say, a little while since part 3 was written; in fact, I wouldn't be surprised if only Steve B. (sbb1cpa) remembers this series, and by now even he might have forgotten. It all goes back to this position (see the original post and its successors), from the game Karim-Zhu Chen, Gibtelecom Masters 2008:



Despite the even material and opposite-colored bishops, White is better and even managed to win. When I first replayed the game (unannotated here; the endgame above starts after Black's 60th move), I was almost shocked by the result. Upon taking a closer look, my opinion changed, but not completely. It seemed on good old-fashioned general principles that such an endgame ought to be a draw. Over time, my opinion changed, though proving a win is also quite difficult.

I offered this ending as an exercise to the readers, and they came through beautifully (and hopefully learned a lot in the process). I too learned something from the exercise - and from my readers - and would like to offer several general principles and provisional conclusions (to put it oxymoronically).

(1) An obvious reminder: opposite-colored bishop endings can be won, even when the material is even and there are no passed pawns. (Of course, White starts with a passed pawn here, but the winning tries all involve giving it away.)

(2) A slightly less obvious corollary: opposite-colored bishop endings can be drawn, even when the weaker side is down a pawn or two.

(3) As in many other endings, and perhaps in chess in general, it's rarely possible to win without utilizing the "principle of two weaknesses". (A "weakness", in this context, refers to something the defender has to protect or defend: an enemy passer or a weak pawn, for example.)

(3a) If the defender's can stop multiple passers on a single diagonal, then those passers may only count as one weakness.

(3b) Sometimes the "weaknesses" are static, like distinct passed pawns, but sometimes they're more dynamic, like potential king penetration. (As we'll see, both sorts of weakness pairs come into play in our ending.)

(4) Let's turn to specifics. When I was first trying to win this endgame against the computer, I found ways to break through with the king to the kingside, winning the h6 pawn doesn't necessarily win, even if the White king can find its way back out. (Example: White retains his a-, c-, g- and h-pawns, Black his a-, c- and g-pawns. As long as Black's king can get to h8 it's a draw: the bishop protects the g-pawn when it's attacked or goes to b4 if White's king journeys cross-country to the queenside.)

(5) Likewise, White can sometimes win the c- and even the a-pawn, and still not win! (You can find such a line in the first main analysis paragraph of the second game file linked at the end of this post.) The basic drawing setup is this: Black's king is on d6 and his bishop is on the a7-g1 diagonal. In this way, the pawns are stopped and White's king can't get to Black's kingside. If White's king goes to d3, Black plays ...Ke5. If White's king goes to a6, Black plays ...Kc7.

(6) The winning method, then, seems to be this: White must win a queenside pawn, but do so in a way that doesn't involve giving up the chance to occupy the d5 square. That square is key for White, because it allows him to play c5 (it's often important for White's c-pawn to break that barrier) and because it gives his king access to Black's kingside pawns. And then, and perhaps only then, Black's defensive resources will be overtaxed. His bishop can control the c-pawn, but his king can't both deal with White's inevitable passed h-pawn and with White's king returning to the queenside to further advance the c-pawn.

You can find some specific analysis here. The first game is a compilation of the readers' analyses, with an occasional comment of my own interspersed. The second game presents a bit of my own analysis of 61.d6. I present two independent paragraphs of analysis, both starting with that move. The first shows White failing to win, despite winning both queenside pawns, but the second presents a White win, utilizing the method outlined in point (6).

Some time ago on this blog, there was a discussion about how lost a position should be before one resigned. One opinion expressed a preference for a delayed resignation, so as to allow amateurs to see how exactly the win ought to be achieved. As a general rule, I'm not sure I agree, but it has to be said that the following example helps my interlocutor's case.



White has just played 81.f6 and Keres resigned. Black is indeed losing, and even if the players weren't more than strong enough to figure out over the board why Black is lost, there had been two adjournments prior to this point. For us, however, it might not be immediately evident. It's a good exercise to work out how White wins this, especially against best defense by Black.

The solution, when you're ready for it, is here.

Last week I offered this position



and presented a variation to go with it: 1...Bd8 2.Kb3 Bxa5 3.Bxa5 Kxa5 4.Kc4 Kb6 5.Kd5 Kc7 6.Ke5 Kd7 7.Kxf5 Ke7 8.Ke5 Kf7 9.f4 Ke7 10.f5 Kf7 11.f6 Kf8 12.Ke6 Ke8 13.f7+ Kf8 14.Kf6 h6 15.h4 h5 16.Ke6 and wins.

The initial challenge was to work through the line and see what improvements were possible - there are quite a few. From a practical perspective, the following finesse isn't the most important, but from an instructional and aesthetic point of view it is:

1...Bd6!! Let's assume things proceed as in the original, once White defends the pawn: 2.h3 Bc7 3.Kb3 Bxa5 4.Bxa5 Kxa5 5.Kc4 Kb6 6.Kd5 Kc7 7.Ke5 Kd7 8.Kxf5 Ke7 9.Kf5 Ke7 10.f5 Kf7 11.f5 Kf7 12.f6 Kf8 13.Ke6 Ke8 14.f7+ Kf8 15.Kf6. So far everything is the same, with the seemingly trivial difference that White's pawn is on h3. But that's all the difference in the world, as 15...h5! draws on the spot (16.Kg6 h4 17.Kg5 Kxf7 18.Kxh4=, or 17.Kf6 stalemate; 16.h4 stalemate). (The above is replayable here.)

So the new task (if you don't use an engine or other external helps, it will prove incredibly difficult) is to try to find an improvement for White somewhere after 8...Ke7 in the second line. It's a fantastic exercise if you try it, whether or not you succeed in solving it.

Rather than making a lot of little posts, I'm going to economize my time and lump everything together.

Finished Event: The Mecking-Greenfeld match wound up a 2-2 tie - all four games were drawn.

Ongoing Event: The first round of the World Cup event in Baku was spectacular. Most of the games were drawn, but all were hard-fought and interesting, and some (e.g. Svidler's draw) were picturesque to boot.

Fischer: On the ChessBase site (link in the right sidebar), there's a link to an article on the wrangling over Fischer's estate. (An aside: I'm curious if the information there about Russell Targ is correct - I read somewhere else that he was not interested in pursuing claims on Fischer's will on behalf of his nieces.)

How to Analyze: There's a great article by Alex Cherniack ("A Knight's Tale") on the Boylston Chess Club website, in which he analyzes a knight ending he recently lost in great detail. At some later point, I hope to look at his analysis carefully, but the greatest value of the piece is seeing what he did and using it as a model for one's own games. It's a lot of work, sure, but think of the payoff! Not only that, it becomes fun once one gets used to doing it. Best chess article I've seen so far this year.

This is the first of a series of posts based on the following position:



It's Black to move, and here's an initial variation to get you started:

1...Bd8 2.Kb3 Bxa5 3.Bxa5 Kxa5 4.Kc4 Kb6 5.Kd5 Kc7 6.Ke5 Kd7 7.Kxf5 Ke7 8.Ke5 Kf7 9.f4 Ke7 10.f5 Kf7 11.f6 Kf8 12.Ke6 Ke8 13.f7+ Kf8 14.Kf6 h6 15.h4 h5 16.Ke6 and wins. (Replayable here.)

Work through the line (but not with your engines, for goodness' sake), see what improvements come to mind, and we'll continue this series soon.

Last week's show covered the famous knight ending from Marco-Maroczy, Kolisch Memorial 1899, and during the show I presented, refuted, and counter-refuted some analysis by Charles Sullivan. (See the comments here.) I think my analysis extends the discussion past what was on his website, but at the end of the day, he's right: Marco could have drawn with 50.Kg1, preventing Black's king from penetrating on the kingside. It will cost White the c-pawn, but that seems to be a loss he can afford. More details here.

Endgame guru Karsten Müller's new column on the Chess Cafe website (permalink here) revisits Bobby Fischer's endgame play, honing in on his 6th game victory in the final Candidates match against Tigran Petrosian in 1971. (But see also the exercises at the end of the article, as well as this earlier Müller column.)

The puzzle was this: Give White a king and three pawns, none of which are doubled, and Black a bare king, and find some arrangement of the forces where it's White to move and the position is still drawn.

And here, again, is the hint: White's king is on h1 and all the pawns are on the kingside.

The solution, at last, is here.

The problem, given last Thursday, was this:

Give White a king and three pawns, none of which are doubled, and Black a bare king, and find some arrangement of the forces where it's White to move and the position is still drawn!

Here's a hint: White's king is on h1 and all the pawns are on the kingside. The solution will be given on Tuesday. (Feel free to comment that you got the solution, but not what it is. Thanks.)

Ilija Golichenko. (Though the year is young - maybe someone will top this.) He's a talented young Ukranian, but despite his FM title (a title given to practically anybody these days), he's going to be in for some ribbing from his friends after failing to deliver checkmate with bishop and knight against bare king. Have a look.

Regular Chess Mind reader Andrey S. writes in with a neat puzzle: give White a king and three pawns, none of which are doubled, and Black a bare king, and find some arrangement of the forces where it's White to move and the position is still drawn! It can be done, believe it or not. I was (painfully) close to solving it without a hint, but didn't actually get it until I received one. We'll do the same here: in a couple of days I'll give the hint Andrey gave me, and then a day later the solution will be provided.

Enjoy it!

Here was the position given in the previous post, with Black to move, from the game Marshall-Chigorin, Barmen 1905:



There were two tasks for the enterprising reader. First, to assess the position; second, to determine what Black ought to play. Got it solved? Click below when you're ready for the answer.

From Marshall-Chigorin, Barmen 1905



It's Black to move. First, assess the position: is White better, Black better, or is it equal? Second, what should Black do? Answers tomorrow.