In his 14th-century work, "Tsurezuregusa" ("Essays in Idleness"), Buddhist monk Yoshida Kenko observed that "houses should be built with summer in mind."

Japanese summers are as hot and humid now as they were then, and good ventilation was essential to comfort long before air conditioning.

A whole culture evolved around ryo — ways of mitigating the heat that are as much a frame of mind as an actual lowering of the ambient temperature.