The United States and allied countries installed a strong military presence and advanced weapons at bases along the line.
The PLA's anniversary came four days after five Chinese warships finished a historic trip, during which the Chinese navy for the first time entered the Pacific through the Soya Strait, known in Russia as La Perouse Strait, between the Russian island of Sakhalin and the Japanese island of Hokkaido.
The Chinese vessels passed through the strait to train in the West Pacific after a joint naval drill with Russia in the Japanese Sea. It was the first time the Chinese navy has conducted high-sea training right after a major drill, with no rest.
On July 25, the ships crossed the Miyako Strait between Japan's Miyako and Okinawa islands on their return voyage to Qingdao, headquarters of the North China Sea Fleet. The move marks the first trip by the Chinese navy circumnavigating the Japanese archipelago.
Japan sent frigates and aircraft to monitor the Chinese fleet at a short distance.
Ministry of National Defense spokesman Geng Yansheng called for rational views on the training, adding that all countries have the right to navigate these waters and channels in the western Pacific Ocean.
Wu Dahui, a military and international studies expert at Tsinghua University, said the Chinese vessels went through the Soya Strait six hours after 18 warships of the Pacific Fleet sailed there.
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