Chess Knightmare

Chess Knightmare and Turing’s Dream
May 31, 2012
By IM Ken Regan

Viswanathan Anand retained his chess world championship title yesterday, by defeating challenger Boris Gelfand in a rapid-chess playoff after the twelve regulation games ended in a 6-6 tie. Yet the match—the most important in chess—was by most accounts not very exciting. Ten of the twelve games were draws, seven with agreement before Move 30 which is disallowed in many tournaments. Many of their moves had been prepared using computers, often toward or beyond Move 20.

Today I ask why computers playing among themselves have produced livelier games than recent matches of humans equipped with computer preparation.

Anand’s third straight match win since gaining the world title in 2008 is impressive. His play can often be exciting, though his results last year were lackluster. Gelfand earned the right to challenge by winning last year’s Candidates’ Match-Tournament in Kazan, Russia. In that event 27 of 30 regulation games were drawn and most matches were decided in similar fast-paced tiebreaks, which some deem akin to a penalty-kick shootout in soccer.

Fears of chess becoming “played out” go back even before the 1927 world championship match between Alexander Alekhine and José Raúl Capablanca, in which 32 of 34 games featured the same opening. What hypes the fear now is that we may have the technology to actually play much of chess out. This feeling was revealed by the number of people taken in by a hoax last month that the King’s Gambit had been exhaustively analyzed to a draw.

However the computers themselves play few draws against each other, and show a degree of human-appreciable inventiveness that Alan Turing could only have dreamed about, unless he had lived to see 85 let alone 100.

What Price High Standards?

According to my statistical model of player move choice mentioned here, this match had the highest standard in chess history. Based on computer analysis of the twelve regulation games, my model computes an “Intrinsic Performance Rating” (IPR) for Anand of 3002, and 2920 for Gelfand. Each is about 200 points higher than their current Elo ratings of 2791 and 2727, respectively. My analysis eliminates moves 1–8, moves in repeating sequences, and moves where one side is judged to have a clearly winning advantage, the equivalent of being over three pawns ahead.

To be sure, I ascribe most of this difference to their use of computer-prepared moves, in short games with relatively few “original moves.” Not only do the programs’ ratings ramp over 3200, home analysis can run them longer and stronger than the game-time settings used to compile those ratings. Still, the players had those moves in their head as they sat down computer-free at the board, and if what matters is the quality of the moves made by their hands regardless of where they came from, then this was history’s human chess pinnacle.

My work also hints that the Elo rating of perfect play may be as low as 3600. This is not far-fetched: if Anand could manage to draw a measly two games in a hundred against any perfect player, the mathematics of the rating system ensure that the latter’s rating would never rise above 3500, and if Gelfand could do it, 3400. Perfect play on both sides is almost universally believed to produce a draw, even after a few small slips. All this raises a question:

Does the higher draw tendency of recent top-level matches owe inevitably to their coming within a few hundred intrinsic rating points of perfection?

The fairest ones to ask are the computers, for they have now played far more games at this level than have we humans. And perhaps surprisingly, their answer seems to be No. The recent 19th World Computer Chess Championship received an IPR over 3000 from my model, yet 22 of 36 games ended in victory. The 2010 WCCC had 35 wins from 45 games, while the 2009 WCCC had 33 from 45, and this month’s International CSVN Tournament had only 7 draws in 28 games. Why?

Full article here.