Rybka wins World Computer Chess Championship

10/6/2008 – The US program Rybka won the 16th World Computer Chess Championship that was held in Beijing, China, a full point ahead of its nearest rival, the British program Hiarcs. Third, a point behind, was the Israeli program Junior, followed by Cluster Toga and then Shredder. The hardware used in the event ranged from a 40-core system to a Nokia cell phone. Final report.

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16th World Computer Chess Championship

This tournament was held from September 28th to October 5th 2008 in the Beijing Golden Century Golf Club, Fangshan, Beijing, China. It was part of the Computer Games Championship, with 28 different games like chess, draughts, checkers, Go, backgammon, etc. The final standing in the chess tournament was as follows:

The victory of Rybka was hardly surprising, since this program is dominating the computer rating lists and was running on the most powerful hardware in Beijing. The performance of the British program Hiarcs, the oldest in the field, was very impressive. In the final round Hiarcs beat the German program Shredder, which in the past has won many world championship titles. The Israeli program Junior, also a former world champion, finished a clear point behind Hiarcs in third place. Here a dramatic game from the final round:

Junior - Rybka [B28]
WCCC 16th Beijing (9), 04.10.2008
1.e4 c5 2.Nf3 a6 3.c3 e6 4.d4 d5 5.e5 Bd7 6.dxc5 Bxc5 7.Bd3 Qc7 8.0–0 Ne7 9.Re1 Ng6 10.Nbd2 Qb6 11.Nd4 Nc6 12.N2b3 Ngxe5 13.Nxc5 Qxc5 14.Bf4 Nxd3 15.Qxd3 0–0 16.Qg3 Nxd4 17.Bd6 Qb6 18.cxd4 Rfc8 19.Be5 g6 20.Qf4 Qd8 21.Re3 Rc2 22.Rh3 f5 23.Rg3 Be8 24.h4 Qe7 25.Rc1 Rac8 26.Rxc2 Rxc2 27.h5 Bf7 28.a3 b5 29.Bd6 Qd8 30.h6 Qf6 31.Bc5 Be8 32.Qb8 Kf7 33.Qd6 Rc1+ 34.Kh2 Kg8 35.Re3 Qh4+ 36.Rh3 Qf6 37.b4 Re1 38.f4 Re4 39.Qb6 g5 40.fxg5 Qf7 41.Kg1 Rg4 42.Qd8 f4 43.Rf3 Qg6 44.Be7 Qb1+ 45.Rf1

The position had looked promising for White, and according to the Rybka operator Hans van der Zijden the opponent Junior was showing a score of +3.59. But Rybka surprised the Israelis with a rook sacrifice: 45...Rxg2+! "This can only mean one thing: perpetual check," writes Hans. And Rybka was able to prove it: 46.Kxg2 Qe4+ 47.Kg1 Qe3+ 48.Rf2 Qg3+ 49.Kf1 Qh3+ 50.Ke2 Qe3+ 51.Kd1 Qd3+ 52.Rd2 Qb1+ 53.Ke2 Qe4+ 54.Kf1 Qf3+ 55.Ke1 Qh1+ 56.Kf2 Qh2+ 57.Kf3 Qg3+ 58.Ke2 Qe3+ 59.Kd1 Qb3+ 60.Rc2 Qd3+ 61.Kc1 Qxa3+ 62.Kb1 Qb3+ ½–½.

Computer Chess World Champion Vasik Rajlich, author of Rybka

The program Rybka is well known to our readers – Version 3 was launched by ChessBase in July this year. It won the 15th World Computer Chess Championship in Amsterdam last year and so was the defending champion in Beijing. Author IM Vasik Rajlich mentions Lukas Cimiotti, who provided some awesome hardware for the event: an overclocked 40-core (5x2x4) Harpertown cluster. "Lukas also spent about two weeks working with me to make sure that everything ran properly," Vasik writes. "We must have had more than 100 phone conversations related to this. For what it's worth, in self-play, the performance of this Rybka configuration seems to be around 100 Elo higher than that of Rybka 3 running on a normal overclocked Skulltrail. The search tree is shaped differently, giving the entity a somewhat different playing style. I find it quite attractive – the play is very precise. There is some food for thought here in the area of normal multi-processor search. Lukas is a regular in the Playchess engine room and no doubt anyone who is curious can learn more there."

Vas Rajlich experimenting with hardware in his Budapest flat

The program Hiarcs (pronounced "high-arks") has a long history. It was originally developed by Mark Uniake (pronounced You-nee-ack) more than twenty years ago, and today it is available on a number of platforms (PC, Macintosh, handheld devices). Hiarcs' playing style is very aggressive, with a distinctive liking for attacking the opponent's king. This often leads to dynamic exciting games which are played on a knife-edge. Hiarcs is written entirely in 'C' and it searches around an order of magnitude less positions per second (average 1,8 million) than most of its competitors. However, it makes up for this apparent slow speed by clever searching and accurate evaluation. The program uses many selective search extension heuristics to guide the search and incorporates a sophisticated tapered search to resolve tactical uncertainties while finding positionally beneficial lines.

Junior is an Israeli program developed as a hobby by Amir Ban and Shay Bushinsky. In 2006 it won the 14th World Computer Chess Championship in Turin, Italy, in 2004 the 12th WCCC in Ramat-Gan, Israel, and in 2002 the 10th WCCC in Maastricht, Holland. 

Cluster Toga is a German system running a parallelized version of the program Toga (based on Fruit). The hardware used in Beijing was a 24-core cluster. The German program Shredder, which scored a disappointing 50% in this event, has, like Junior, won multiple world computer chess championships in the past: the 11th WCCC in Graz, Austria, in 2003, and the 9th in Paderborn, Germany, in 1999. Shredder is written in ANSI-C and therefore it can easily compiled on various hardware platforms.


Prices for Rybka

Multi-processor version: Deep Rybka 3   99.90 Euro
Single processor version: Rybka 3   49.99 Euro
Rybka 3 Book   24.99 Euro

Note that Rybka 3 includes a database of one million games, and that the purchase of the program entitles you to one year of access to the chess server Playchess.com. Rybka 3 is a UCI engine, with 32 and 64-bit versions included in the package. Rybka can be made the default engine in ChessBase 10.

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