"When you put many children in a quiet box, some of them get really nervous," says Japanese architect Takaharu Tezuka, founder of Tezuka Architects. "In this kindergarten, there is no reason for them to get nervous. There is no boundary." Speaking at TEDxKyoto on his design for an open-air kindergarten in Tokyo, Tezuka discusses his playful and unorthodox approach to the creation of the eccentric building. The unconventional space blurs interior with exterior while accommodating a varied program of athletic, educational and relaxed space. According to Tezuka, the concept was based on a progressive philosophy employed by the school administration: "The principal says: if the boy doesn't want to stay in the room, let him go. He will come back eventually." On children, Tezuka's own philosophy is one of empowerment: "Don't control them. Don't protect them too much. They need to tumble sometimes. They need to get injured. That makes them learn how live in this world."