There are various strategic purposes for companies to form international joint ventures. They are often implemented when a sole venture is too risky or too costly. As an international joint venture grows by learning from a partner company, the joint venture is more likely to be able to contribute to parent companies, yet the possible threat of competition between partner companies increases. This paper identifies balancing cooperation and competition based on structural attachment as a significant factor in maintaining a stable relationship between partner companies in international joint ventures. We investigated the case of a Korea-Japan automotive stamping die joint venture manufacturer which has existed for almost 30 years. This case shows that, even though there is possible instability in maintaining international joint ventures, partner companies can adopt moderating factors such as structural interdependency between local partners and foreign partners, implicit segregation of market and product, and additional collaboration or cooperation in overseas markets.