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News | Feb. 28, 2023

Submarine Group 7 Hosts Trilateral Theater Anti-Submarine Warfare Tabletop Exercise and Working Group in Yokosuka

By Lt.Cmdr. Robert Reinheimer, Commander, Submarine Group Seven Public Affairs

Commander, Submarine Group 7 hosted their counterparts from the Japan Maritime Self-Defense Force (JMSDF) and Royal Australian Armed Forces personnel from the Australian Headquarters Joint Operations Command (HQJOC) for a trilateral theater anti-submarine warfare (TASW) tabletop exercise and working group at Fleet Activities Yokosuka, Feb. 14-16.

The exercise ran for the first two days, with simulated anti-submarine warfare (ASW) assets from each country operating together to improve interchangeability and warfighting effectiveness.

After the exercise’s three scenarios were complete, the U.S. Navy, JMSDF, and HQJOC personnel collaborated on lessons-learned and briefed their findings to senior leadership during the Commander, Pacific Fleet Trilateral TASW Working Group, Feb. 16.

"Our teams interact on a daily basis, and identifying and resolving issues together as a combined force is key to our interchangeability in all domains of anti-submarine warfare," said Rear Adm. Rick Seif, commander, Submarine Group 7. "This tabletop exercise was a great opportunity to review lessons learned from our real-world trilateral operations and exercises, and to test new tactics, techniques, and procedures that improve our readiness."

Other senior participants from each country included: Rear Adm. Blake Converse, U.S. Pacific Fleet deputy commander; Rear Adm. Joaquin J. Martinez de Pinillos, vice commander, U.S. 7th Fleet; JMSDF Vice Adm. SAITO Akira, Commander-in-Chief of the Self-Defense Fleet; and JMSDF Vice Adm. TAWARA Tateki, commander, Fleet Submarine Force; Royal Australian Air Force Air Vice-Marshal Michael Kitcher, Deputy Chief Joint Operations; and Royal Australian Navy Commodore Michael Harris, Director of General Maritime Operations.

The exercise included multiple scenarios which tested the capabilities of the three countries’ anti-submarine forces. The goal of the exercises were to remove friction points between forces in order to enhance our combined information sharing, coordination, and communication.

“Holding this tabletop exercise and working group was a great step in identifying the common issues that our forces face when working together,” said Harris. “The Indo-Pacific region is a large area of operations, so our ability to work together to accomplish tasks and goals will only make us a stronger and more effective team.”

The lessons learned will assist commanders in improving real-world integration at sea including future plans for embarked liaison officers, logistics support, and smoother communication paths and processes between the three countries.

Submarine Group 7 directs forward-deployed, combat capable forces across the full spectrum of undersea warfare throughout the western Pacific, Indian Ocean, and Arabian Sea.

For more news from Commander, Submarine Group 7, visit