Photo/IllutrationThe Maritime Self-Defense Force submarine Kuroshio sails off Etajima, Hiroshima Prefecture, on Aug. 27 after leaving the MSDF Kure base in Kure, also in the prefecture, earlier in the day. (Takateru Doi)

  • Photo/Illustraion

Demonstrating freedom of navigation, a Japanese submarine for the first time conducted drills in the South China Sea where China is constructing military facilities, according to Japanese government sources.

The Defense Ministry secretly dispatched the Kuroshio, a Maritime Self-Defense Force submarine, which conducted anti-submarine drills on Sept. 13 with three MSDF destroyers that were on a long-term mission around Southeast Asia, they said.

The ministry had conducted anti-submarine drills only in sea areas around Japan, they added.

The South China Sea is a strategic sea lane used by many Japanese commercial vessels.

“The sea area has vital importance (for Japan),” said MSDF Chief of Staff Yutaka Murakawa.

China is constructing artificial islands there by reclaiming reefs to make the sea area a military stronghold.

The ministry apparently aimed to keep China in check with the freedom of navigation operation in the open seas.

“The (Sept. 13) drill was one more step forward than before (to contain China’s moves in the South China Sea),” said a high-ranking MSDF official.

According to the sources, the Kuroshio left the MSDF Kure base in Hiroshima Prefecture on Aug. 27. After navigating through the East China Sea and the Bashi Channel, located between Taiwan and the Philippines, it entered the South China Sea.

The MSDF destroyers the Kaga, Inazuma and Suzutsuki left the Kure base in Hiroshima Prefecture or the Sasebo base in Nagasaki Prefecture on Aug. 26. After sailing through the Bashi Channel, they entered the South China Sea.

The three destroyers continued to navigate in the South China Sea and the Indian Ocean while holding joint exercises with the U.S. Navy aircraft carrier Ronald Reagan and the Philippine navy’s vessels around the Philippines.

The Kaga, the MSDF’s largest destroyer with a standard displacement of 19,950 tons, is the same class as the destroyer Izumo, which the ministry is considering retrofitting as an aircraft carrier.

The Kuroshio and the three destroyers linked up in an open sea area in the South China Sea on Sept. 13.

The destroyers and the helicopters they carry aboard trained to detect a submarine. The submarine also sharpened its capabilities to approach vessels without being detected.

The drill was held within the nine-dash line, the boundary of an area in which China claims jurisdiction.

“A drill in the open sea is a justified act based on the freedom of navigation stipulated in international law,” a Japanese government official said.

On Sept. 17, the Kuroshio was expected to enter Cam Ranh in Vietnam, the most important stronghold for the country to defend the South China Sea. It marks the first time an MSDF submarine has entered the port in the city.

The visit was apparently intended to show China that Japan and Vietnam are strengthening cooperation in the field of defense.

China constructed a runway on an artificial island in the Spratly Islands and deployed surface-to-air missiles on the Paracel Islands. It is also deploying vessels in the Scarborough Shoal off the Philippines.

China is also believed to have constructed a base for nuclear-powered submarines, which can launch ballistic missiles, in Hainan Island in the southernmost part of the country and have deployed those submarines there.

The South China Sea has apparently become a stronghold for the nuclear-powered submarines.

“Unless we contain the movements of those submarines there, the submarines will be able to freely advance into the Pacific Ocean through the Bashi Channel. The advances will greatly affect the security of the Pacific Ocean, which is important for both Japan and the United States,” said a high-ranking SDF official.