As a junior, he showed a prodigious talent for the game and in 1967, at twelve years of age, he won the British under-14 Championship. At fourteen, he was London Under-18 Champion for the 1969/70 season and less than a year later, at just fifteen years of age, he proceeded to Oriel College, Oxford, to study mathematics. At the time, it was said that he was Oxford's youngest undergraduate since Cardinal Wolsey. Graduating in 1973, he went on to gain his doctorate in 1978 with a thesis on finite H-spaces, and remained at Oxford University as a mathematics lecturer until 1981, when he became a professional chess player.
In 1975, he became the European Junior Champion. He gained the Grandmaster title in 1978 and was British champion in 1979. Nunn has twice won individual gold medals at Chess Olympiads. In 1989, he finished sixth in the inaugural 'World Cup', a series of tournaments in which the top 25 players in the world competed. His best performance in the World Chess Championship came in 1987, when he lost a playoff match against Lajos Portisch for a place in the Candidates Tournament. He won the prestigious Hoogovens tournament (held annually in Wijk aan Zee) in 1982, 1990 and 1991.
He achieved his highest Elo rating of 2630 in January 1995. Six years earlier, in January 1989, his then rating of 2620 was high enough to elevate him into the world's top ten, where he shared ninth place. This was close to the peak of the English chess boom and there were two English players above him on the list; Nigel Short (world number three, 2650) and Jonathan Speelman (world number five, 2640). Nunn has now retired from serious tournament play and hasn't played a rated game since August 2006.
As well as being a strong player, Nunn is regarded as one of the best contemporary authors of chess books. He has penned many volumes, including
Secrets of Grandmaster Chess which won the British Chess Federation Book of the Year award in 1988 and
John Nunn's Best Games which took the award in 1995. He is the director of chess publishers Gambit Publications. Chess historian Edward Winter has written of him:
A polymath, Nunn has written authoritative monographs on openings, endings and compositions, as well as annotated games collections and autobiographical volumes. As an annotator he is equally at home presenting lucid prose descriptions for the relative novice and analysis of extreme depth for the expert.
Nunn is also involved with chess problems, composing several examples and solving as part of the British team on several occasions. On this subject he wrote
Solving in Style (1985). He won the World Chess Solving Championship in Halkidiki, Greece, in September 2004 and also made his final GM norm in problem solving; he won the World Championship again in 2007. He is the third person ever to gain both over-the-board and solving GM titles (the others being Jonathan Mestel and Ram Soffer; Bojan Vu?kovi? has been the fourth since 2008).
Since the mid-1990s, Nunn has been actively engaged in data mining from chess endgame tablebases. The products of this work include the books
Secrets Of Rook Endings,
Secrets of Minor-Piece Endings, and
Secrets Of Pawnless Endings. These books include human-usable endgame strategies found by Nunn (and others) by extensive experimentation with tablebases, and new editions have come out and are due as more tablebases are created and tablebases are more deeply data-mined. Nunn is thus (as of 2004) the foremost data miner of chess endgame tablebases. This work corresponds to the endgame part of the work of Berlekamp, Conway et al. in dots-and-boxes, Hex and other games.
He is married to Petra Fink-Nunn, a German chess player with the title Woman FIDE Master. They have a son, Michael.
