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a mainframe chess program of the 70s, developed by British scientists from Atlas Computer Laboratory in Chilton, Oxfordshire and Harwell Atomic Energy Research Establishment. When Alex Bell left Atlas Laboratory in 1969, his fellow Peter Kent took over his chess program Atlas, which was a reproduction of Nils Barricelli's program in Algol. With the help of John Birmingham the program was rewritten to PL/I, and in 1973, Alex Bell, back in Chilton, joined the team to develop the chess playing program Minimax algorithm Tester, Master. In 1974, for the upcoming WCCC 1974 in Stocholm, chess tutor John Waldron was recruited to implement chess knowledge and opening book. When Alex Bell left Chilton a second time in 1975, Master was further improved by Peter Kent and John Birmingham as sole authors [1].
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Master was a Shannon Type A program with progressive deepening, examining the full width of moves, subject only to pruning by the various algorithms, that is Alpha-Beta , (deep) razoring and marginal forward pruning. The Killer heuristic and static evaluation (in the upper part of the tree) was used in move ordering.SOMA
Similar to SOMA, Master had no quiescence search, but an attempt to compute a static evaluation for non-quiescent positions, archived by giving values for threats to pieces as well as captures, considering pins and x-rays, control to center squares and squares near the king. The value of threats by the player to move is greater than that of the player who has just moved, producing an element of tempo in the evaluation function. Apparently later version of Master used Mate at a Glance, that is were able to detect various mates without further search.Feed-Over
A so called Feed-Over Technique was applied, which saved the most important parts of the tree in a kind of refutation table, also reused after a move has been selected from the root for initial move ordering.Tournament Play
Master competed at the first three World Computer Chess Championships, the WCCC 1974 in Stocholm, the WCCC 1977 in Toronto and the WCCC 1980 in Linz. Master won the two European Computer Chess Championships, the ECCC 1976 in Amsterdam, and the ECCC 1979 in London.Master at IFIPS
Alex Bell describes the development of Master, and the tournament experience - excerpt [4]:One of the programmers at Atlas, Peter Kent, had taken over the program and modified it to maximise the number of squares controlled. This, combined with a few other improvements, had produced a much stronger program - as Peter later wrote.
At this point a very energetic programmer from Harwell Atomic Energy Research Establishment, John Birmingham, became interested. He translated the program, plus all the new improvements, into PL/I in about 6 weeks of his spare time and also extended the depth of the search. I would say at this point that England at last had a program comparable to MACHACK and we ambitiously christened it MASTER-Minimax Algorithm teSTER; if nothing else we had the patent on a good name.
In March 1974 David Levy, the regular referee and one of the organisers of the American ACM tournaments, rang me up - did I know of any good English chess programs? And, if so, would they like to enter the first IFIPS World Computer Chess Championship which would take place at Stockholm in August? So MASTER was entered, and for the first time we - John, Peter and myself - stopped developing the program sporadically ad hoc and seriously thought about how to improve it. One big problem was that none of us was (or is) a good chess player and by then the program was beginning to beat us occasionally.
So a fourth member of the team was recruited - John Waldron, a sound county level player. From this point MASTER slowly began to copy Waldron's style and, with the program now searching 6 plies deep plus a crude form of a new technique (feedover), it took part in the IFIP first World Championship in Stockholm, winning 2, losing 2 and coming about 5th out of 13 programs using 2 hours of time of the Rutherford's 360/195.
On the last night, having won two easy games, MASTER again met a tough opponent, RIBBIT from Canada. At one point in this game Peter Kent, who was in Stockholm, told us that if MASTER won then there was a chance that it could play off for the championship but, unfortunately, TECH 2 had been a costly game in sabbatical time and MASTER was set to play very quickly, missed its chances and gave away a piece. The position at move 54 was (Fig. 10) and Peter Kent asked me if MASTER was saying it wanted to resign.
During the tournament we had not been linked directly to Peter Kent in Stockholm but had been relaying our moves algebraically through London where another chess program was also competing in the tournament. This relay had caused us to use a voice code for the moves (ABLE, BAKER, CHARLIE, DOG, EASY, FOX, GEORGE, HOTEL) and, oddly enough, we never sent or received a bad move.
Selected Games
WCCC 1974
WCCC 1974, round 3, Master - Tell [5]WCCC 1974, round 4, Ribbit - Master [6]
WCCC 1977
WCCC 1977, round 2, Master - Chess 4.6 [7]WCCC 1980
WCCC 1980, round 3, Bebe - Master [8]See also
Publications
[9]External Links
Chess Program
Misc
References
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