Much of what architecture students learn in the studio is «tacit knowledge.» They develop the skills and sensibilities of architectural and urban design with practice, often under the supervision of instructors and peers, not by studying textbooks. Yet, despite its importance, we know relatively little about how this tacit form of knowing is transmitted. Within the research network TACK / Communities of Tacit Knowledge, we tried to open up the «black box» of knowledge production in the design studio.