Shortly before World War I, he left his family company for good and started traveling abroad, devoting himself to chess. Abroad he took part in numerous chess tournaments, winning many of them. His international chess career started in 1926. That year he became the first Polish Champion winning in Warsaw. The same year he also won a notable tournament in Munich (+4 –0 =1) ahead of Rudolf Spielmann and Efim Bogoljubov. He placed second (behind Max Euwe) in the second and last World's Amateur Championship in 1928.