The houses, built for American airmen and their families right after the World War II, were sold into private hands when the airmen moved out. In the late 60's or early 70's, young people began moving into the houses along Route 16. These 'U.S. Base Houses,' as they were called, attracted many young musicians such as Haruomi Hosono, Chu Kosaka, Kyozo Nishioka and Minako Yoshida, and the 'Houses' in Sayama became not only a focus for music fans but also of social interest.
For many young people, the Park, with its western-style houses around it, was the place where they could most directly feel America. To stretch the point a bit, Hyde Park was a fascinating 'Door' opening to American culture.
http://hmf-sayama.jp/e/concept.html