Flohr's playing ability peaked in the mid-1930s, when he became one of the world's strongest players and a leading contender for the World Championship. He became champion of Czechoslovakia in 1933 and 1936 and played in many tournaments throughout Europe, generally finishing amongst the top three. Notable victories were at Bad Sliač in 1932, where he shared first place with Milan Vidmar; Scheveningen in 1933; Bad Liebenwerda in 1934 with 9½/11; Barcelona in 1935 where he tied for first with George Koltanowski; Moscow 1935 where he tied for first place with future World Champion Mikhail Botvinnik; Poděbrady in 1936 with the score of +10 −1 =6; and Kemeri in 1937 where he shared the top spot with Vladimir Petrov and Samuel Reshevsky. During this period, he had several other notable high finishes, such as Bern 1932 (tied for second with 11½/15, after World Champion Alexander Alekhine); Zürich 1934 (tied for second with 12/15, again trailing Alekhine); and Pärnu 1937 (second behind Paul Felix Schmidt).