Our paper investigates the inherent tensions between the local embeddedness of highly tacit knowledge and the global sourcing of ‘open’ knowledge or innovation. A single case study design enabled us to perform a thorough and detailed analysis of inter-firm collaboration and open innovation within the specific context of the Amsterdam denim cluster, which is internationally renowned as a centre of denim expertise with an important focus on
sustainability. In-depth interviews and workshops were held with several stakeholders involved in Denim City, such as campus managers and denim brands. We find that open search strategies have more depth than breadth when the collaboration is focused on radical innovation. We also shed light on the complex relation between appropriability and openness
when collaboration involves competing firms. We also show that cognitive proximity of partners plays a role in the global sourcing of knowledge.