The previous game was a good example of the importance of a single square. This game was decided by Euwe's brilliant exploitation of a weak square...f6 and is very instructive.
Euwe needs no introduction, but his opponent, Salo Flohr, is not too well known today.
Salomon Flohr (November 21, 1908 – July 18, 1983) was a leading Czech GM of the mid-20th century, who became a national hero in Czechoslovakia during the 1930s. His name was used to sell many of the luxury products of the time, including Salo Flohr cigarettes, slippers and eau-de-cologne. See Edward Winter's article on chess and tobacco.
Flohr dominated many tournaments of the pre-World War II years and by the late 1930s was considered a contender for the World Championship. However, his patient, positional style was overtaken by the sharper, more tactical methods of the younger Soviet echelon after World War II. Flohr was also a well-respected chess author, and an International Arbiter.
In 1937 FIDE nominated him as the official candidate to play Alekhine for the World Championship, but with World War II looming, it proved impossible for Flohr to raise the stake money in Czechoslovakia, so the plans were dropped. The next year Flohr was one of the eight elite players invited to the AVRO tournament in 1938. He finished last and that put an end to his chances of a match with Alekhine.
The German invasion of Czechoslovakia in 1938 meant Flohr, as a Jew, was in serious personal danger so he stayed in The Netherlands for a while until he and his family fled, first to Sweden, and then, with the help of Botvinnik, to Moscow where he became a Soviet citizen.
After the War he was still considered a contender for the World Championship and played in the 1950 Candidates Tournament in Budapest. However, he finished tied for last with 7 out of 18, and never entered the World Championship cycle again, preferring to concentrate on journalism.
The evolution of his style of play was interesting. When he came into prominence after Bled 1931 his play was inventive and showed great imagination to the point that he was called a master of tactical play. Gradually a noticeable change took place. He began to evade tactical play in favor of quiet positional play and endings where he tried to win on sheer technique and as a result, he began producing dull games that lacked any imagination. This style allowed him to grind out wins against weaker players, but against world class players, it was not enough and he drew most of his games against such opponents.