See his favorite Openings on Chess Boards
Machgielis “Max” Euwe, PhD (May 20, 1901 – November 26, 1981) was a Dutch Grandmaster, mathematician, and author. He was the fifth player to become World Chess Champion (1935–37). Euwe also served as President of FIDE, the World Chess Federation, from 1970 to 1978.
Euwe was noted for his logical approach and for his knowledge of the openings, in which he made major contributions to chess theory. Paradoxically his two title matches with Alexander Alekhine were displays of tactical ferocity from both sides. But the comments by Kmoch and Alekhine (below) may explain this: Euwe “strode confidently into some extraordinarily complex variations” if he thought logic was on his side: and he was extremely good at calculating these variations. On the other hand he “often lacked the stamina to pull himself out of bad positions”.
Alekhine was allegedly more frank in his Russian-language articles than in those he wrote in English, French or German. In his Russian articles he often described Euwe as lacking in originality and in the mental toughness required of a world champion. Gennadi Sosonko thought Euwe’s modesty was a handicap in top-class chess (although Euwe was well aware of how much stronger he was than “ordinary” grandmasters).
Vladimir Kramnik also says Euwe anticipated Botvinnik’s emphasis on technical preparation, and Euwe was usually in good shape physically because he was a keen sportsman.