Karuizawa 640 is a distinctive hospitality facility completed in 1984, located in the serene mountain town of Karuizawa in Nagano Prefecture. Designed collaboratively by Studio A and the Environmental Design Institute, this structure exemplifies thoughtful architectural integration with its natural surroundings. The building's design reflects the design principles of the 1980s while demonstrating a commitment to harmonizing modern accommodation with the peaceful alpine environment. Its strategic placement in the Shukugami area showcases sensitive site planning that respects the landscape's character. This landmark represents an important example of resort architecture from Japan's period of economic growth and remains noteworthy for its approach to blending contemporary hospitality design with environmental consciousness.