Advanced Chess is a form of chess where each human player uses a computer chess program to explore the possible results of candidate moves. The human players, despite this computer assistance, are still fully in control of what moves their "team" (of one human and one computer) makes.
Advanced Chess (sometimes called cyborg chess, centaur chess or Ivanov chess) was first introduced by grandmaster Garry Kasparov, with the objective of a human player and a computer chess program playing as a team against other such pairs.
Many Advanced Chess proponents have stressed that Advanced Chess has merits in:
- increasing the level of play to heights never before seen in chess;
- producing blunder-free games with the qualities and the beauty of both perfect tactical play and highly meaningful strategic plans;
- giving the viewing audience an insight into the thought processes of strong human chess players and strong chess computers, and the combination thereof.
A variation or superset of Advanced Chess is freestyle chess, where consultation teams are also allowed. It is common for "regular" Advanced Chess single man/machine teams (also called "centaur play", to differentiate between pure-man or pure-machine play) to take part in freestyle tournaments. Freestyle tournaments are frequently more informal than regular chess tournaments, even though the level of play can be significantly higher.
The concept was already common in the 1970s: "An interesting possibility which arises from the 'brute force' capabilities of contemporary chess programs is the introduction of a new brand of 'consultation chess' where the partnership is between man and machine." The concept of computer-assisted chess tournaments originated in science fiction, notably in The Peace War written by Vernor Vinge in 1984.
The former world champion grandmaster Garry Kasparov, who retired from competitive chess in 2005, has a long history in playing "Man vs. Machine" events. Among the most important are his matches against IBM's computer Deep Blue, which Kasparov defeated in February 1996, scoring 4–2 in a 6-game match, and lost to, 3 1⁄2–2 1⁄2, in a May 1997 rematch. This 1997 match was famous, as it was the first time in the history of chess in which a world champion had been defeated by a computer. After this spectacular match, and many other matches against computers, Garry Kasparov had the idea to invent a new form of chess in which humans and computers co-operate, instead of contending with each other. Kasparov named this form of chess "Advanced Chess".
The first Advanced Chess event was held in June 1998 in León, Spain. It was played between Garry Kasparov, who was using Fritz 5, and Veselin Topalov, who was using ChessBase 7.0. The analytical engines used, such as Fritz, HIARCS and Junior, were integrated into these two programs, and could have been called at a click of the mouse. It was a 6-game match, and it was arranged in advance that the players would consult the built-in million games databases only for the 3rd and 4th game, and would only use analytical engines without consulting the databases for the remaining games. The time available to each player during the games was 60 minutes. The match ended in a 3–3 tie. After the match, Kasparov said:
My prediction seems to be true that in Advanced Chess it's all over once someone gets a won position. This experiment was exciting and helped spectators understand what's going on. It was quite enjoyable and will take a very big and prestigious place in the history of chess.
Regular Advanced Chess events have been held since in León each year, with some inconsistency after 2002. The Indian grandmaster Viswanathan Anand is considered the world's best Advanced Chess player, winning the three consecutive Advanced Chess tournaments in Leon in 1999, 2000 and 2001, before losing the title to Vladimir Kramnik in 2002. After the loss to Kramnik, Anand said:
I think in general people tend to overestimate the importance of the computer in the competitions. You can do a lot of things with the computer but you still have to play good chess. I more or less managed to do so except for this third game. In such a short match, against a very solid and hard to beat opponent, this turned out to be too much but I don’t really feel like that the computer alone can change the objective true to the position.
Both players sit in a typical chess-playing room, equipped with fast PCs of equal hardware strength. It is the duty of the tournament organizers to make sure that the players are familiar with the pertinent hardware and software. Unlike the traditional face-to-face chess, the players usually face their respective computers. Each player is typically allotted one hour of thinking time (as was the time control used in all Advanced Chess events in León), though the particular tournament regulations may vary regarding this matter.
During the match, the players will typically form strategic plans in their minds, then enter the candidate sequences of moves into the computer to analyze and make sure there are no blunders and other possible holes. The human player will compare the merits of each candidate sequence after having seen the computer's analysis, and may even introduce a new variation if time permits. The player will typically play out the move which he or she has established (with computer help) to be strongest. If there are two or more moves which the computer considers to be of equal strength (such situations are frequent), the human player will use their own strategic skills and experience and analytical judgment capabilities to decide which move to play. The humans are in charge during the whole match, and are formally free to play any moves they consider the best, at their own discretion. During the opening, the players may consult a large database of opening moves and variations, containing information about who played a particular variation, when it was played, and with what success, though a particular tournament's rules may prohibit using databases in such manner.
During the whole game, the players' computer monitors are projected onto large screens, making it possible for the viewing audience to watch how the strongest players decide about their moves and make their plans. Typically there will be a commentator in a separate room, equipped with the identical hardware as players, which will be used to help provide a commentary to the audience—this way the audience is given the real insight into the thought processes of the strongest players.
Although Advanced Chess play is at the highest level when performed by the top grandmasters, it is not limited to them. Anyone can play Advanced Chess, sometimes with the same success as the strongest grandmasters. Occasionally, average players have been able to achieve a performance rating higher than the one of the computer programs they were using, and on rare occasions higher than the ratings of top grandmasters.
It has been debated, due to the peculiarities of the human–computer team, whether the human should be considered the Advanced Chess player, or rather the team itself should be considered the Advanced Chess player. It is the prevailing view that, because the human subordinates the computer in a meaningful intent to win a chess game, and that the human is the one who makes the final decision about the move to be played, the human should be considered the Advanced Chess player. Some[who?] have also argued that the term "computer-assisted player" should not be used for an Advanced Chess player, as the key element is cooperation, not assistance.
On the Internet
The ubiquity of the Internet and a high number of commercial and free Internet chess servers has made it possible for anyone to play Advanced Chess over the Internet. There has not been organized Internet Advanced Chess play in quite a while, though, and few Internet chess systems have regulated rated Advanced Chess play.
The world's largest organization for Advanced Chess on the Internet is the Advanced Chess Organization—CCO (this organization used to be known as Computer Chess Organization, and therefore kept the acronym CCO for historical reasons). CCO organizes regular Advanced Chess events, most of which take place on The Free Internet Chess Server (FICS) or the correspondence website http://www.cowplay.com. One need not be a CCO member to participate in its tournaments, though the organization stresses that membership is highly desirable. CCO Advanced Chess events on the Internet usually employ unrated play, because rated Advanced Chess play is still unregulated by most Internet chess systems, and use of computers in rated games is considered cheating and ruled out. CCO proposes that Internet chess servers introduce a third category of player—the "Advanced Chess player", among the existing human and computer players, latter of which usually labeled by "(C)", and that Advanced Chess players should be associated with a special Advanced Chess rating category. CCO points out that most Internet chess servers already have software-driven mechanisms which allow players to choose the types of the opponents they wish to play, therefore making it possible for a particular player to exclude all Advanced Chess players, should he/she not wish to play them.
The trend might be changing as Advanced Chess is offered on the correspondence chess server at FICGS as the default mode of play, with special, unrated, "no engines" tournaments being the exception, rather than the rule.
There have been, worldwide, a number of Advanced Chess tournaments online, defined Freestyle Chess Tournaments by Centaur (Centaur = human player + computer).
The most important were the PAL/CSS Freestyle Tournament, sponsored by the PAL Group in Abu Dhabi (UAE), which had a high level of play and the winners, in chronological order, were: Zacks (Steven Cramton and Stephen Zackery, USA), Zorchamp (Hydra (chess), UAE), Rajlich (Vasik Rajlich, Hungary), Xakru (Jiri Dufek, Czech Rep.), Flying Saucers (Dagh Nielsen, Denmark), Rajlich (Vasik Rajlich, Hungary), Ibermax (Anson Williams, England) and Ultima (Eros Riccio, Italy).
Similar tournaments were organized by the FICGS server. The FICGS Freestyle Cup was won by Eros Riccio (1st and 3rd editions), David Evans (2nd edition) and Alvin Alcala (4th and 5th editions).
Infinity Chess, the server operated by the CCGM Arno Nickel, have organized their own freestyle tours and freestyle matches (Welcome Freestyle Tournament, Christmas Freestyle Tournament, IC Freestyle Masters, Infinity Freestyle Tournament, Infinity Chess Freestyle Battle 2014 and 8-legs of Centaur Weekend Tours). Eros Riccio was the most successful Infinity Chess freestyle player, winning the tours up to 2012. Anson Williams led the team that won in 2014.
The Internet Chess Club also held their own freestyle tour dubbed as 1st Ultimate Chess Championship 2015 and won by Alvin Alcala.
Infinity Chess has developed two special Elo rankings for the centaurs. The first, based on results achieved in Advanced Chess tournaments from 2005 to 2013, lists Sephiroth (Eros Riccio) in first place with 2755 points. . The second, based on tournaments played from 2010 to 2014, lists Intagrand (David Evans, Anson Williams and Nelson Hernandez) in first place with 2689 points. 
A computer engine ends first in the freestyle Ultimate Challenge tournament. The first ranked human plus computer player came in at 3rd place.
Unless both sides have agreed, the use of a computer in any chess game is considered cheating. This cheating should not be confused with Advanced Chess play or with computer against computer tournaments.
- Michie, Donald (1972-08-17). Programmer's gambit. New Scientist. pp. 329–332. Retrieved 22 September 2013.
- ChessBase Archived February 9, 2005, at the Wayback Machine
- "Chessevents". Archived from the original on 2005-02-27. Retrieved 2005-03-05.
- , Free Internet Correspondence Games Server.
- FICGS titles
- International Freestyle Top 100
- International Freestyle Top 20
- Advanced Chess information on figcs.com