Harmony Danchi is an environmentally conscious public housing complex completed in 2006 in Kaseda, Minami-Satsuma, Kagoshima Prefecture. Designed by Yasumitsu Matsunaga of the Institute for Modern Architecture and the Urban Design Laboratory of Kagoshima University's Department of Architecture, this multifamily residential project exemplifies sustainable design principles. The complex features innovative wooden flat-roof construction with rooftop greening, integrating ecological considerations into its architectural design. As an exemplary model of environmental coexistence housing, it demonstrates how contemporary public housing can balance residential functionality with ecological responsibility and sustainable urban living practices.