As the world's second- and third-largest oil consumers, no two countries depend on the Malacca Strait more than China and Japan. But that doesn't mean they work together to keep the strait safe.
The Malacca Strait is an area where the geo-political struggle between the two Asian giants is being played out.
Japan has long been a leader in drawing attention to the dangers of the Malacca Strait and in providing assistance. Japan's Nippon Foundation is a non-profit association influential on maritime policy in the strait.
In 2001, Japan initiated the Regional Co-operation Agreement on Anti-Piracy in Asia, a pact that facilitates co-operation on maritime safety issues between 16 nations.
The Chinese have been moving more quietly, using some of the diplomatic capital they've assiduously acquired over recent years. Insiders say that Malaysia's refusal to allow international patrols was at least partly a result of Chinese pressure to not allow US military ships to patrol the strait. A new partnership with Indonesia, announced in April, includes provisions for maritime co-operation.
Both countries worry about disruption of energy imports.