Watsuji's three main works were his two-volume 1954 History of Japanese Ethical Thought, his three-volume Rinrigaku (Ethics), first published in 1937, 1942, and 1949, and his 1935 Fūdo. The last of these develops his most distinctive thought. In it, Watsuji argues for an essential relationship between climate and other environmental factors and the nature of human cultures, and he distinguished three types of culture: pastoral, desert, and monsoon.[3]