Wednesday, August 31, 2016

X-ray attacks

Last year I wrote on my blog that computers achieve autonomy in defining opening-theory but at chess-compositions they remained till recently invisible.  Dr Mohammed Azlan Iqbal is a pioneer whom wrote a program able to autonomously create chess-compositions. The artistic element is considered by many the last bastion of chess in which computers won't equal for a long time humans. So it wasn't a real surprise that his work got a lot of critics and many made firewood of his program. On Chessbase the author tried to defend his brainchild by stating that not the same criteria were used of beauty as is the case in the world of compositions but the damage was already done. Although I think the program is pretty clever and has potential, there is little chance that we get still new releases with improvements.

It does't mean that engines are useless for composers. As well for verification as for the creation of the problems/ compositions they often play an important role. Sometimes even in such magnitude that people are questioning the added value of the composer to the work of the computers. Compositions with 6-7 pieces can all be found in the lomonosov 7 men tablebases so some don't consider them anymore as unique.

Engines also show us regularly some amazing ideas. How often we think that we played a good game but at home we are still surprised by incredible turns which the computer can calculate in a nano-second. Maybe the loyal reader still remembers my article interferences with a fantastic piece-sacrifice from my practice. This time I want to show some amazing ideas based on x-ray attacks which I met (relatively) recently. Just for information I give you a description of an x-ray attack. An x-ray attack is a tactic in which 2 pieces of the opponent are positioned on 1 line. If you attack 1 piece, and this piece moves, then on that same line there is still the second piece. In some way you can look through the first piece to the second piece. Therefore we call it an x-ray attack.

In the step-method students are often training x-ray attacks but that doesn't mean that experienced players won't miss one, at contrary. Also with this theme there are many levels of complexity. Lets have a look at the example below. It is a variation of a game played in the 2015 club-championship of Deurne which didn't pop up during the game but was important for the evaluation of the position.
[Event "Klubkampioenschap Deurne r8"] [Date "2015"] [Round "?"] [White "Brabo"] [Black "De Cock, R."] [Result "*"] [ECO "C96"] [WhiteElo "2318"] [BlackElo "1650"] [SetUp "1"] [FEN "r2q1rk1/1b2bppp/p2p1n2/1p6/2nNPB2/7P/PPB2PP1/RN1QR1K1 w - - 0 15"] [PlyCount "3"] 15. Nd2 $1 $146 {(I played the weaker and still known Nf5 in the game.)} Nxb2 $2 {(Necessary is Ne5 with a slight disadvantage for black.)} 16. Qb1 { (Only now it appears that black has no good square to retreat the knight because of the x-ray attack on the bishop of b7.)} *
A second example which I should not omit is the fantastic 12. Qg3 played at the rapid-tie-brake of the quarter-finales of the Fide World Cup at Baku, Azerbaijan. The Chinese prodigy Wei Yi used only a few seconds for this move but I am convinced that he knew about this possibility in advance thanks to the great book  Move First Think Later. A short review of this book I gave on my blog see I knew it.
[Event "FIDE World Cup"] [Site "Baku"] [Date "2015.09.22"] [Round "4.5"] [White "Wei, Yi"] [Black "Ding, Liren"] [Result "1/2-1/2"] [ECO "C24"] [WhiteElo "2734"] [BlackElo "2782"] [SetUp "1"] [FEN "rnb2r1k/pp2qBpp/2p5/4N2n/4PQ2/8/PPP2PPP/RN2K2R w KQ - 0 12"] [PlyCount "40"] [EventDate "2015.09.11"] [EventRounds "7"] [EventCountry "AZE"] [Source "ChessBase"] [SourceDate "2015.10.08"] 12. Qg3 {(Only a few seconds did the Chinese prodigy spent on this move. However the move was already a few years known by the book "Move First Think Later" in which the Dutch IM Willy Hendriks celebrates it as his most beautiful one.)} Rxf7 (12... Nxg3 {(Of course black does not capture the queen in the game but the refutation is really nice.)} 13. Ng6 hxg6 14. hxg3 Bh3 15. Rxh3 Qh4 16. Rxh4#) 13. Nxf7 Qxf7 14. Qd6 Be6 15. Nc3 Nd7 16. O-O-O Re8 17. Rhf1 Bc4 18. Rfe1 Ne5 19. b3 Ba6 20. Kb1 h6 21. f3 Nf4 22. Rd2 Kh7 23. Red1 Re6 24. Qb8 Qf6 25. Na4 Be2 26. Rc1 b6 27. Nc3 Ba6 28. Rcd1 Nc4 29. bxc4 Qxc3 30. Qxf4 Qb4 31. Ka1 Qc3 1/2-1/2
It is hard to find a more beautiful example with the x-ray attack but a few months ago the Russian top-grandmaster Ian Nepomniachtchi hit the jackpot. There exist many games in which a bishop is sacrificed at h7 but then the pawn is already at h4. Here it even works by playing h4 later.
[Event "TCh-RUS Men 2016"] [Site "Sochi RUS"] [Date "2016.05.05"] [Round "5.2"] [White "Nepomniachtchi, I."] [Black "Sjugirov, S."] [Result "1-0"] [ECO "C42"] [WhiteElo "2703"] [BlackElo "2674"] [SetUp "1"] [FEN "rn1q1rk1/ppp2ppp/3p4/6b1/2PP2b1/2NB1N2/PP3PPP/R2QK2R w KQ - 0 10"] [PlyCount "45"] [EventDate "2016.05.01"] [WhiteTeam "SSM Legacy Square Capital Moscow"] [BlackTeam "Zhiguli Samara region"] 10. Bxh7 {(A marvelous idea based on a very well hidden x-ray attack. Ian later admit that he did not find this move at the board which is something very honest for a 2700 player.)} Kxh7 11. h4 Bd2 (11... Bxf3 12. hxg5 Kg8 13. Qxf3 $18) (11... Bh6 12. Ng5 Qxg5 13. hxg5 Bxd1 14. Rxd1 $16) ( 11... Be7 12. Ng5 Kg8 13. Qxg4 $16) (11... Bxh4 12. Qd3 Kg8 13. Rxh4 f5 14. Rh2 $16) (11... Re8 12. Kf1 Kg8 13. hxg5 $16) 12. Qxd2 Re8 13. Kf1 Bxf3 14. Qd3 Kg8 15. Qxf3 Nd7 16. Rd1 Qf6 17. Qxf6 Nxf6 18. f3 d5 19. c5 b6 20. cxb6 axb6 21. Kf2 b5 22. a3 b4 23. axb4 Rab8 24. b5 c6 25. Rhe1 cxb5 26. Rxe8 Rxe8 27. Rc1 Ra8 28. Nxb5 Ra4 29. Rc8 Kh7 30. g4 Rb4 31. Nd6 Rxd4 32. Kg3 1-0
Not only did Ian tell later on twitter that this was for him one of the most beautiful and unique ideas he ever played but also that it wasn't something he discovered himself.

Engines are by many players cursed because they destroy chess. On the other hand we must admit that they also allow us to discover a lot of beauty even if the engines aren't programmed for that purpose. Surely when dealing with x-ray attacks, an engine doesn't suffer from certain visual barriers. Do you still know unique examples of your own practice or of professionals then I invite you to share them below in a reaction.