{"id":4323,"date":"2016-07-11T12:12:50","date_gmt":"2016-07-11T20:12:50","guid":{"rendered":"http:\/\/www.danamackenzie.com\/blog\/?p=4323"},"modified":"2016-07-11T12:16:23","modified_gmt":"2016-07-11T20:16:23","slug":"extreme-traitor-pawns","status":"publish","type":"post","link":"https:\/\/danamackenzie.com\/blog\/?p=4323","title":{"rendered":"Extreme traitor pawns"},"content":{"rendered":"

I’m going to take a short break from my series of 6 memorable games, partly because I haven’t decided on game #4 yet and partly because of a cool e-mail that I got from Larry Smith. Larry, you might recall, was one of my teammates at the U.S. Amateur Team West tournament this year. He doesn’t write a blog, but he does send out periodic e-mails that could be described as blog-like. On June 19, he wrote about a game, Pavel Simacek versus Evgeny Postny, that went down to a bishop and wrong-color rook pawn endgame.<\/p>\n

Every chess player above C class should know that\u00a0 the K + B + RP versus K endgame is drawn if the queening square is on the opposite color of the bishop. The defender puts his king down on the queening square and it can never be chased away; at best, it can be stalemated.<\/p>\n

But things get a little bit more interesting when there are more pawns on the board! That was the case in Simacek-Postny. If the defender has one or two pawns, paradoxical situations can arise where the position is not drawn or where the draw requires something a little bit different from the brain-dead plan that I just described. This is an extreme example of “traitor pawns” — pawns that turn against the player they belong to.<\/p>\n

Here is the key position in Simacek-Postny that caught Larry’s eye, and mine too.<\/p>\n

\"simacek<\/a>Position after 80. … Bh2. White to play.<\/em><\/p>\n

FEN: 8\/8\/8\/3k4\/7p\/3P1K2\/6P1\/6b1 b – – 0 80<\/p>\n

If White could just get his king to h1 it would be a “brain-dead” draw. But the traitor pawn at g2 stands in his way, and Postny has also done his best to keep White’s king out of the corner, by putting his bishop on h7. So, how does White save the game?<\/p>\n

The answer is to get rid of the traitor pawn! Simacek played 81. g4!<\/strong> Strictly speaking, there are many ways for White to draw, because the d-pawn allows him to buy some time. But sooner or later he must <\/em>play\u00a0this move, or else g3. Otherwise\u00a0Black will win. By playing g4 right away, Simacek eliminates any doubt. If Black plays 81. … hg then White plays 82. Kg2! and the point is revealed: Black’s bishop has no way out of the corner. Once the d-pawn is gone, White can simply shuttle his king between h1 and g2 forever. If Black’s king ever gets close enough to threaten g3-g2+, it will be stalemate. If Black tries to defeat this plan by not taking the d-pawn, then White will not play Kh1; he’ll just push the d-pawn and force Black to take it.<\/p>\n

In the game Postny didn’t take, but after 81. … h3 82. g5 Be5 83. Kf2<\/strong> the players agreed to a draw<\/strong>. White’s king is headed to h1, and if Black tries to keep it out with 83. … Bd4+, then 84. Kg3 wins the h-pawn and the game is drawn.<\/p>\n

The pawn on d3 made this a less than perfect teaching example, because White did not need to find the drawing resource right away. If we take away that pawn, it’s a different story.<\/p>\n

\"simacek<\/a>White to play and draw; Black to play and win.<\/em><\/p>\n

FEN: 8\/8\/8\/3k4\/7p\/5K2\/6Pb\/8 b – – 0 1<\/p>\n

Here if it’s White’s move, he draws with either 1. g3 or 1. g4, as before. If it’s Black’s move, he wins with 1. … Bg6!,<\/span> blockading the traitor pawn and not allowing it to reconsider its nefarious ways. Now it’s too late for White’s king to head to the corner with 2. Ke2 Ke4 3. Kf1 Bh2 4. g4<\/span> (or g3) h3!<\/span> The bishop on h2 and the pawn on h3 make a barrier that White’s king cannot cross, and after 5. g5 Kf5 6. Kf2 Kxg5 7. Kf3 Kh4<\/span> White’s king will gradually be forced back, inch by inch.<\/p>\n

Neither Larry nor I had previously seen this motif of playing g3 (or g4) and trapping the bishop on h2. Has anyone seen it in a book? Could you give me a reference?\u00a0It’s really essential for understanding this ending (B + RP vs. NP), so it seems inconceivable that it hasn’t been noticed before.<\/p>\n

In all of these cases it didn’t matter whether White plays g3 or g4. Naturally, Larry was curious whether there are any cases where it does matter. So he got into the online Nalimov tablebases, and sure enough he found some. They’re all very closely related, so I’ll just show you one prototype.<\/p>\n

\"simacek<\/a>White to move and draw.<\/em><\/p>\n

FEN: 8\/8\/8\/5k2\/7p\/5K2\/6Pb\/8 w – – 0 1<\/p>\n

If Black’s King is on f5 (as here) or h5, then White draws with 1. g4+!\u00a0but loses if he plays 1. g3?? h3. If Black’s king is on g5, then White is simply lost, because either 1. g4 or 1. g3 is met by 1. …\u00a0h3! Finally, if Black’s king is on\u00a0f6, g6, or h6,\u00a0then White draws with 1. g3! h3 2. Kg4 but loses if he plays 1. g4??\u00a0h3! Pretty cool, huh?<\/p>\n

Something about the Simacek-Postny endgame was vaguely familiar, and this weekend I figured out why! This was a game I played in the Western States Open in Reno in 2001, against a National Master named Bill Heywood. It is a perfect complement to the Simacek-Postny game and the related positions that Larry found.<\/p>\n

\"heywood<\/a><\/p>\n

Position after 40. Kd4. Black to move.<\/em><\/p>\n

FEN: 8\/4k1p1\/1R4Bp\/8\/bP1K3P\/4r3\/8\/8 b – – 0 40<\/p>\n

Here I was Black, and on the last move of the time control I played the excellent practical move 40. … Re1!<\/strong> This is the right move on general principle because\u00a0Black needs to activate his rook. In fact, I managed to draw the game after seven more moves.<\/p>\n

But what if Black plays the more forcing move 40. … Re6? In my annotations after the game, I wrote, “It would have been easy and wrong to play 40. … Re6? 41. Rxe6+! Kxe6. Even though White\u00a0has the ‘wrong rook pawn,’ Black cannot draw by sacrificing his bishop for the b-pawn. The reason is that we will eventually reach a ‘stalemate position’ with the Black king on h8 and White’s king on f8. Then White will move his bishop. Black will be forced to play 1. … g6 or 1. … g5 2. hg h5 3. g7 mate — practically a helpmate! Ironically, if Black could just remove either the h-pawn or the g-pawn or both, it would be a draw — but with both pawns, he loses.”<\/p>\n

This fascinating annotation is half right and half wrong.<\/p>\n