US-Japan 2JA 2026 Mine Warfare Exercise Highlights Real Combat Challenges in Mutsu Bay Over 15 Days

The mine warfare exercise 2JA 2026, which took place in Mutsu Bay from July 9 to 24, did not feature flashy missile launches or fleet battles. However, reading the announcement from the U.S. Pacific Fleet reveals details that remind us of what truly can stop maritime traffic: mines.

Small Participating Forces, Heavy Responsibilities

The U.S. side deployed the Avenger-class mine countermeasures ship USS Chief MCM-14, the Explosive Ordnance Disposal Mobile Unit 5, and personnel from Mine Warfare Group 7. The Japan Maritime Self-Defense Force (JMSDF) contributed the Mogami-class frigate "Niyodo" FFM-7, the Uraga-class mine warfare support ship "Bungo" MST-464, and the Awaji-class minesweeper "Awaji" MSO-304, along with a group of minesweepers from the Hatsushima and Sugashima classes, as well as YDT-02, P-1, P-3C, MCH-101, and EOD units. The significance lies not in a mere ceremonial training but in the continuous search, detection, sweeping, and disposal operations carried out over 15 days.

Focus on Mine Warfare Beyond the Southwest Islands

Recent discussions have tended to concentrate on the Taiwan Strait and the Southwest Islands. However, the location of Mutsu Bay presents a different issue. The Tsugaru Strait, the Sea of Japan, and the maritime routes around Hokkaido have been critical points for anti-submarine and mine warfare since the Cold War. Considering the expansion of the Chinese Navy's operational range and the presence of the Russian Pacific Fleet, the ability to protect ports and straits in northern Japan is not a secondary mission.

Participation of Mogami-class FFM Indicates Change

Noteworthy is the participation of the "Niyodo." The Mogami-class has a standard displacement of approximately 3,900 tons, equipped with a 127mm gun, anti-ship missiles, and VDS/TASS-type anti-submarine equipment, differing from traditional mine warfare vessels. There is a visible trend to expand mine warfare beyond the scope of just minesweeping units, integrating surface combatants, aircraft, and EOD into joint operations. This also serves as training to align U.S.-Japan command and communication procedures.

According to the U.S. Pacific Fleet, the participating forces removed simulated minefields and refined communication and tactical procedures in a joint environment.

Deterrence Against China Relies on Quiet Capabilities

The Ministry of Defense's June 2026 report outlines that China is expanding its activities in the East China Sea, the Pacific, and the Sea of Japan. While the intentions of the adversary are always changing, capabilities accumulate. If a mine threat arises around Japan's ports, supply lines, and narrow waterways in a crisis, ships cannot be deployed with just F-35s and long-range missiles. Mine countermeasure capabilities may seem outdated, but they actually influence the initial response speed of the alliance.

In the author's view, the value of this 2JA 2026 exercise lies not in fostering goodwill with the U.S. Navy, but in confirming how many days the JMSDF can continue "humble tasks." The unresolved risk lies more with personnel than with the number of assets. If personnel capable of simultaneously operating minesweeping, EOD, and patrol aviation over the long term cannot be secured, mine warfare capabilities will remain a mere reassurance on paper.