The "Ki no iE" is a small Home overlooking the Hat Rock in Abashiri given to a boy with Prader-Willi Syndrome. A growing appetite, developmental delay, and short stature commonly characterize the syndrome. We planned life in this home to become a natural diet and exercise regimen. For example, we designed a "hallway-integrated kitchen" that is always organized for others to see and a "variety of steps" and "bouldering wall" to encourage natural exercise in daily life. Also, the sight of the Ainu people praying on Hat Rock synchronizes with everyone's wish for a peaceful life at the entrance. Hat Rock is called Kamui Watara (Rock of God) by the Ainu people. It was a place of prayer before going offshore to hunt sea animals after the drift ice broke. When faced with unexpected difficulties, we built an "entrance to pray" overlooking Hat Rock, where all those who love him can pray for his safety.