Karuizawa Kogen-so is a distinctive lodging facility completed in 1974, designed by Ikeda Design Office. Located in Shiozawa, Karuizawa, Nagano Prefecture, this national guesthouse exemplifies the architectural approach of the 1970s. The building showcases modernist design principles characteristic of that era, thoughtfully integrated into Karuizawa's natural mountain environment. Its functional design prioritizes comfort and accessibility for guests while maintaining aesthetic coherence. The structure represents an important example of Japanese hospitality architecture from the post-war period, reflecting both contemporary design sensibilities and the cultural significance of Karuizawa as a leisure destination.