Guy McCrossan Haworth

Performance and prediction: bayesian modelling of fallible choice in chess

Evaluating agents in decision-making applications requires assessing their skill and predicting their behaviour. Both are well developed in Poker-like situations, but less so in more complex game and model domains. This paper addresses both tasks by using Bayesian inference in a benchmark space of reference agents. The concepts are explained and demonstrated using the game of chess but the model applies generically to any domain with quantifiable options and fallible choice. Demonstration applications address questions frequently asked by the chess community regarding the stability of the rating scale, the comparison of players of different eras and/or leagues, and controversial incidents possibly involving fraud. The last include alleged under-performance, fabrication of tournament results, and clandestine use of computer advice during competition. Beyond the model world of games, the aim is to improve fallible human performance in complex, high-value tasks.

Understanding Distributions of Chess Performances

This paper studies the population of chess players and the distribution of their performances measured by Elo ratings and by computer analysis of moves. Evidence that ratings have remained stable since the inception of the Elo system in the 1970’s is given in three forms: (1) by showing that the population of strong players fits a straightforward logistic-curve model without inflation, (2) by plotting players’ average error against the FIDE category of tournaments over time, and (3) by skill parameters from a model that employs computer analysis keeping a nearly constant relation to Elo rating across that time. The distribution of the model’s Intrinsic Performance Ratings can therefore be used to compare populations that have limited interaction, such as between players in a national chess federation and FIDE, and ascertain relative drift in their respective rating systems.

The European Declarative System, database, and languages

The EP2025 EDS project, which is developing a highly parallel information server that supports established high-value interfaces, is discussed. The motivation for the project, the architecture of the system, and the design and application of its database and language subsystems are described. The Elipsys logic programming language, its advanced applications, EDS Lisp, and the Metal machine translation system are examined.<<ETX>>

A Comparative Review of Skill Assessment: Performance, Prediction and Profiling

The assessment of chess players is both an increasingly attractive opportunity and an unfortunate necessity. The chess community needs to limit potential reputational damage by inhibiting cheating and unjustified accusations of cheating: there has been a recent rise in both. A number of counter-intuitive discoveries have been made by benchmarking the intrinsic merit of players’ moves: these call for further investigation. Is Capablanca actually, objectively the most accurate World Champion? Has ELO rating inflation not taken place? Stimulated by FIDE/ACP, we revisit the fundamentals of the subject to advance a framework suitable for improved standards of computational experiment and more precise results. Other games and domains look to chess as demonstrator of good practice, including the rating of professionals making high-value decisions under pressure, personnel evaluation by Multichoice Assessment and the organization of crowd-sourcing in citizen science projects. The ‘3P’ themes of performance, prediction and profiling pervade all these domains.

Position Criticality in Chess Endgames

Some 50,000 Win Studies in Chess challenge White to find an effectively unique route to a win. Judging the impact of less than absolute uniqueness requires both technical analysis and artistic judgment. Here, for the first time, an algorithm is defined to help analyse uniqueness in endgame positions objectively. The key idea is to examine how critical certain positions are to White in achieving the win. The algorithm uses sub-n-man endgame tables (EGTs) for both Chess and relevant, adjacent variants of Chess. It challenges authors of EGT generators to generalise them to create EGTs for these chess variants. It has already proved efficient and effective in an implementation for Starchess, itself a variant of chess. The approach also addresses a number of similar questions arising in endgame theory, games, and compositions.

6-man chess and zugzwangs

With 6-man Chess essentially solved, the available 6-man Endgame Tables (EGTs) have been scanned for zugzwang positions where, unusually, having the move is a disadvantage. Review statistics together with some highlights and positions are provided here: the complete information is available on the ICGA website. An outcome of the review is the observation that the definition of zugzwang should be revisited, if only because the presence of en passant capture moves gives rise to three new, asymmetric types of zugzwang.

WCCC 2017: The 23 rd World Computer Chess Championship

The ICGAs 23rd World Computer Chess Championship started on July 3rd. 2017. The competitors in this select field were CHIRON, JONNY, KOMODO and SHREDDER. The contest was close and set new standards for the event: all podium places required play-offs. Ultimately, KOMODO retained its title, beating JONNY and SHREDDER. The analysis of the games and the pgn file of games are provided here.

WCCC 2016: the 22nd World Computer Chess Championship

In the ICGAs 22nd World Computer Chess Championship in Leiden, six contestants together gave the latest demonstration of the state of the art in chess-playing programs. This article highlights the advances and subtleties exemplified by their play. The new World Champion was KOMODO with JONNY, edged out in the play-off, second and SHREDDER third. GRIDGINKGO, HIARCS and RAPTOR took the remaining places.

WSCC 2016: the World Speed Computer Chess Championship

In the ICGAs World Speed Computer Chess Championship, played at Blitz tempo, the role of the operators is more to the fore, their handspeed being crucial in building up the time available to the chess programs to ponder as necessary. The six contestants of the 2016 World Championship took part and the winner, on tie-break from SHREDDER, was JONNY. KOMODO, the 2016 Chess and Chess Software World Champion was third.

WCCC 2015: The 21st World Computer Chess Championship

Nine chess programs competed in July 2015 in the ICGAs World Computer Chess Championship at the Computer Science department of Leiden University. This is the official report of the event.