Open innovation is important for companies to improve innovation. The right level of openness is crucial - not too closed or too open. The study used simulations to find the best level of openness. Results show that the optimal openness changes depending on the situation. Companies with more holes in their knowledge network should be less open broadly but more open deeply. Companies with high centrality should be more open broadly but less open deeply. In bad institutional environments, companies should be less open. In competitive markets, companies should be more open broadly but less open deeply.