After its defeat of Stockfish there has been talk of Magnus Carlsen taking on the artificial intelligence program but it is, as yet, untested against humans

The eye-catching victory of AlphaZero, the artificial-intelligence program that taught itself to play chess, over the No 1 computer engine Stockfish, has evoked comparisons with human legends.

Garry Kasparov has written a foreword for a newly published book in which he says AlphaZero’s “dynamic, sacrificial style … mirrored my own … AlphaZero prefers piece activity and attacking chances”. He also compares it to “Alexander Alekhine, with dazzling sacrifices and a fondness for unbalanced positions”.

The book is Game Changer by Matthew Sadler and Natasha Regan (New in Chess, £19.95) which features an in-depth analysis by Sadler, a grandmaster and former British champion, of recurrent motifs in AlphaZero’s style which can be adapted by human players.

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Among the many themes which Sadler identifies, AZ likes Harry the h pawn to spearhead its long-term attacks with an advance to h6 which entombs a rook or bishop at h8. In the Queen’s Gambit Exchange it avoids the traditional queen’s side minority attack and will allow Bg4xf3 doubling White’s f pawns to create attacking chances. It values piece mobility highly, and is ready to sacrifice material for a complex initiative.

AlphaZero’s opening repertoire is notable in that it avoids 1 e4 except in themed games, because it believes that 1 e4 e5 is equal. Like Vlad Kramnik, it uses the Berlin Wall 2 Nf3 Nc6 3 Bb5 Nf6. Its principal reply to 1 d4 is the Ragozin Queen’s Gambit, all implying a rather narrow repertoire as Black which, since top grandmasters specialise in prepared lines, is something which at least in theory a future human opponent might exploit.

However, there have been no AZ games published against any humans, and indeed none published against any opponent other than Stockfish. Such games probably happened, for AZ’s creator Demis Hassabis is an expert player while its team also includes Dharshan Kumaran who during his career in the 1990s was a grandmaster and world under-16 champion.

At the back of Game Changer there are two photographs of the authors playing AZ in May last year, but there are no accompanying game moves or even any description of what happened. The only detail given is that Natasha Regan played a Reti Opening.

The overriding impression from Game Changer is that the AZ v Stockfish matches were full of creative ideas, so I went to the website chessgames.com which has a dedicated AlphaZero page with 220 games against Stockfish. What stands out there is something rather different.

Of the 220 games games 123 were marathons of 100 moves or more;123 games, 33 of these, every one drawn, exceeded 200 moves. Several lasted 251 or 255 moves, where there seems to be a termination rule. Human games of over 100 moves are rare and the record length is 269-moves played at Belgrade half a century ago.

The all-time No 1 Garry Kasparov famously lost to IBM Deep Blue in 1997, and the next world champion Vlad Kramnik was beaten by Deep Fritz in 2006 after allowing a mate in one.

After that it became received wisdom that human v computer matches were no longer viable, but America’s Hikaru Nakamura defeated Rybka in a speed game in 2008, and in 2011 and 2018 tied with Komodo receiving small material odds.

LeelaZero is a free open-source engine using the same self-learning method as AlphaZero, and in little over a year it has become one of the strongest competitors. You can watch it or even play it at lichess, and its match currently in progress against Stockfish can be viewed at chessbomb or chess24.

AlphaZero has succeeded in reaching a wider audience with greater media exposure than any of its rivals. Its absence of human opponents could even be deliberate in a quest for what now looks the ultimate pairing, AlphaZero v Magnus Carlsen. Could it happen?

On the face of it, no. Carlsen has stated several times that he is not interested in playing machines, and in rating terms it would be a mismatch, AZ’s 3500 against the world champion’s 2800.

Yet in marketing terms, as a promotion for global chess and as a contest where the audience on a Guardian live blog would dwarf the 550k peak for Carlsen v Fabiano Caruana, it is now a dream, a glittering prize. My guess is that somebody, somewhere, will try to make the dream reality.

As light relief from 200-move computer games, try this miniature from the world blitz silver medallist.

3605 1 Bf2+ Kh5 2 g4+ Kh6 3 Kf6! Kh7 (not Bh7 4 Be3 mate) 4 g5 Kh8 5 Bd4 Kh7 6 Ba1/b2/c3/e5 Kh8 7 g6! fxg6 8 Kxg6 mate.