TOKYO — China’s assertive demarcation of the airspace over the East China Sea hints at an ambitious yet risky long-term strategy of maritime control.

“I thought this would happen one day, but never that they would go ahead so soon,” said a Japanese national security source after China declared its new air defense identification zone last Saturday.

Chinese national security advisers had mooted the idea before. One put the objective this way, according to the source: The Americans and Japanese have their own zones, allowing them to fly in international skies as if they were in their own airspace. China needed one, too.

Read more: http://asia.nikkei.com/Politics-Economy/Policy-Politics/Beijings-grand-vision-of-a-blue-water-Chinese-lake