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. 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.