A rare announcement was made on Monday, September 17, 2018 as the Japanese defense ministry confirmed the submarine Kuroshio, as well as the helicopter carrier Kaga and two other destroyers, the Inazuma and Suzutsuki, took part in an anti-submarine warfare exercise in the South China Sea this Thursday, September 20, 2018.
This was the first time Japan's maritime self-defense force has confirmed a military drill by a Japanese submarine in the disputed waters.
Kuroshio, which left Japan on August 26, visited Cam Ranh in central Vietnam on Monday afternoon in the first port call by a Japanese submarine to a strategically important military base in Vietnam, the most provocative claimant against China's military build-up in the South China Sea.
Japan's defense ministry did not disclose a lot of information on where exactly the exercise was held, but Japan's Asahi newspaper cited sources as saying the Kuroshio joined the other three Japanese warships just southwest of the Beijing-controlled Scarborough Shoal, a territory claimed by the Philippines.
Meanwhile, Chinese foreign ministry spokesman Geng Shuang called on Tokyo to "respect the efforts made by regional countries to resolve the South China Sea issue through talks".
"Act with caution and don't take any acts that could damage peace and stability in the region," he stated.
Beijing claims more than 80 per cent of the South China Sea, through which about US$3.4 trillion worth of global trade travels each year.
The area is also claimed by Vietnam, Malaysia, Brunei, Indonesia, Taiwan and the Philippines. China's military build-up, which has included sending bombers and installing missile systems in the outposts of the disputed waters, has been criticized by the other claimants, as well as the United States.
Meanwhile, Beijing and Tokyo have been seeking reconciliation in the past few months after years of tensions over their growing territorial disputes in the East China Sea and historical grievances from the Second World War.
Japanese Prime Minister Shinzo Abe is expected to visit Beijing next month to mark the 40th anniversary of the signing of a friendship treaty between the two former foes.
A statement given by Zhou Yongsheng, a professor at China Foreign Affairs University in Beijing, said that while Thursday's exercise could cast a shadow over the recent reconciliation, both Beijing and Tokyo would refrain from escalations in the face of pressures from US President Donald Trump's tough-line trade polices.
However, following the launch of a trade war against China, Trump has also threatened to make its Asian ally the target of his next trade outburst.
"Japan wants to contain China in the South China Sea, and this exercise would be a negative influence on the atmosphere, but the general trend of improving bilateral ties is based on mutual interests of the two countries," Zhou said.
"China is looking for increased cooperation and even to gain support from Japan in the face of the trade tensions from the US, while Japan also sees China as a stable market which could also become a leverage in its foreign policy."
In addition, observers warned that the reconciliation between the two rivals remained fragile, given the deep distrust over security.
Last year, Japanese warships took part in naval drills in the South China Sea with the US navy in an apparent show of naval force to contain Beijing in the strategic waters.
