And if the king moves up to h6 to capture the rook after. Re7 will pin the queen and force an exchange. If the white king moves onto the e-file then. In this position Black simply gives checks on h7, g7 and f7.
But there are also more subtle positions, like the following: Most are "pathological" positions in which the defending side can exchange the rook for the queen, or even capture it or deliver mate. Rxf4 1/2-1/2 Pathological positionsīut what about the positions that remain unmarked when the process of calculating an endgame is completed? Of the 1.9 million positions in the Queen vs Rook endgame there are a certain number that end up blank. Instead of resigning, as most players might have done, Boris Gelfand simply challenged his opponent to prove that he could win with the queen. This is what happened at the FIDE World Championship 2001 in Moscow: in the round five playoffs Peter Svidler reached a Queen vs Rook position against Boris Gelfand. The lad had actually worked it out in his head, while lying in bed in the dark.Įven in practical play sometimes top GMs can have their problems. BUT: the next morning at breakfast he said he had found the strategy in the night, and proved it by easily winning test positions against the computer. And once, when the 14-year-old Peter Leko was staying at the Friedels' house, Frederic challenged him. At one event he had Kasparov and Karpov consulting while trying to overcome the computer – they too failed. One of the players dragged GM Artur Jussupow to take on the computer – and had to shell out the ten dollars. Many GMs were not able to win it against the perfect defence of the computer, so for example Walter Browne during a tournament in the 1980s, when he lost a $100 bet by not being able to capture the rook against Thompson's database.įrederic Friedel had a lot of fun with this first endgame database: at one tournament he offered $10 to anyone who could win with the queen. And it was surprisingly difficult to play. The four-piece ending queen vs rook was the first important endgame to be solved in this way. He generated every legal position with K+Q vs K+R – 1,900,000 in all – and working backwards from mates created a list in which every position contained information with the distance to mate (the longest was 61 moves).Ī program that has access to such an "endgame database" – today the term "tablebase" is more commonly used – plays the endgame with absolute perfection – "as well as god", Thompson once quipped. It was done by Ken Thompson back in the early ninteen eighties. One of the first endgames that was exhaustively calculated was the four-piece ending queen vs rook. And this et cetera can run into the millions and billions. Then you mark all positions in which the attacker can achieve a position marked two in one move with a three. Then you mark all positions in which every legal move of the defending side leads to a position marked one, and mark it two. Then you mark all positions in which the attacking side can achieve a zero-position in one move with a one. Then you mark all positions in which one side is mated with a zero. Then you generate every legal position that is possible with the given material. Positions with the attacking side on the move are circles, the defender-to-move positions are squaresĪnd this, in a nutshell, is how it works: first you define the material you want to analyse, e.g. They are fully analysed endgames for which the program has perfect knowledge – it knows the status of every single legal position that is possible with a given material configuration.
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