In the late seventies and early eighties Tadao Ando's architecture and theoretical writings explored the idea of Critical regionalism – the idea of promoting local or national culture within architecture. Ando's interpretation of this was demonstrated by his idea of reacquainting the Japanese house with nature, a relationship he thought had been lost with Modernist architecture. His first projects were for small urban houses with enclosed courtyards (such as the Azuma House in Ōsaka in 1976). His architecture is characterised by the use of concrete, but it has been important for him to use the interplay of light, through time, with this and other materials in his work. His ideas about the integration of nature converted well into larger projects such as the Rokkō Housing 1 (1983) (on a steep site on Mount Rokkō) and the Church on the Water (1988) in Tomamu, Hokkaidō.