Designed by husband and wife Arakawa Shūsaku (1936–2010) and Madeleine Gins (1941–2014) and completed in 2005, this housing complex certainly strikes against the mould: created 'in memory of Helen Keller' the nine units have undulating, ridged floors, spherical dens and ceiling hooks for hammocks and swings. All this is meant to create a sensory experience beyond the visual (though the building is plenty colourful). To see the inside, join one of the monthly public tours.
The tours are in Japanese, but are experiential enough to enjoy without understanding the explanations; tours with English-speaking translators can also be arranged. Some units are occupied by residents, but others are available for short-term stays.
From JR Mitaka Station, take bus 51 or 52 (¥220, 15 minutes, every 10 to 15 minutes) from bus stop 2 on the station's south side and get off at Ōsawa Jūjiro (大沢十字路); you can see the building from the bus stop. Not all buses go this far, so show the driver where you want to go. Bus 1 (¥220, 25 minutes, every 10 to 15 minutes) goes here from Kichijōji Station (south exit, bus stop 3), alongside Inokashira-kōen.