A battle group of the Japan Maritime Self-Defense Force (JMSDF) patrolling the disputed South China Sea has been strengthened with the addition of submarine built to sink warships, the first time the Japanese have combined both surface and undersea warships in a patrol.
Escort Flotilla Four consisting of the helicopter carrier JS Kaga (DDH-184) and two destroyers, JS Suzutsuki (DD-117) and JS Inazuma (DD-105) have been patrolling the South China Sea since August as part of Japan's own freedom of navigation operations (FONOPS).
JMSDF reveals this surface warfare force has been bolstered by the deployment of the JS Kuroshio (SS-596), an Oyashio-class diesel-electric attack submarine armed with American-made UGM-84 Harpoon over-the-horizon, anti-ship missiles, and huge Type 89 homing torpedoes that streak towards their warship targets as far as 50 km away at more than 100 km/h.
The addition of the Kuroshio, one of 11 Oyashio-class attack boats, greatly increases the offensive firepower of Escort Flotilla Four. JMSDF gave no reason for strengthening Escort Flotilla Four. It did acknowledge the flotilla conducted simulated warfare exercises in which the Kuroshio sought to evade detection by her sister warships.
This is also the first time a JMSDF submarine has taken part in a naval warfare drill with surface warships in the South China Sea. Escort Flotilla Four is on a two-month-long patrol. It previously visited the Philippines and will also visit other countries in the region that are members of the Association of Southeast Asian Nations or ASEAN.
Military analysts said the advent of the Kuroshio will anger China because anti-submarine warfare is one of the most serious weaknesses of the People's Liberation Army Navy (PLAN). Undetected, a single submarine can wreak havoc on any surface warship force.
Extensive refits have made the 11 Oyashio-class boats about as lethal as JMSDF's newest submarines belonging to the Sōryū-class.
Geng Shuang, a spokesman of China's Ministry of Foreign Affairs, said China urges Japan to respect the efforts made by regional countries to resolve the South China Sea issue through talks. He said Japan must act with caution and not take any acts that could damage peace and stability in the region.
Earlier this month, Escort Flotilla Four joined forces with the USS Ronald Regan (CVN-76) and her Carrier Strike Group Five in joint exercises in the South China Sea.
