VERTREP Resupply Demonstrated by Japan and the U.S. in the Waters Near Japan during Pacific Atlas 26-1

A small resupply training exercise conducted off the coast of Yokosuka seemed to hold significant meaning for the author. According to a statement from the U.S. Pacific Command, from June 15 to 19, the Japan Maritime Self-Defense Force, the Japan Coast Guard, and the U.S. Coast Guard conducted Pacific Atlas 26-1 in the waters near Japan. Participating were one anti-submarine patrol helicopter from the JMSDF's 21st Air Squadron, the Japan Coast Guard's Shunkō-class patrol vessel "Yumihari" PLH 44, and the U.S. Coast Guard's Legend-class cutter "Midgett" WMSL 757.

The Core of the Training is Continuity, Not Combat

The most noteworthy term in the announcement is not firepower or deterrence, but logistics. In this training, "Yumihari" and "Midgett" conducted VERTREP, or vertical replenishment, using aircraft to transfer supplies at sea. The U.S. side described this as a demonstration of resupply capabilities supporting distributed maritime operations.

At first glance, this may seem like a mundane task. However, considering the SLOC (Sea Lines of Communication) extending from the Nansei Islands to the Japanese mainland and further to Guam, the question of where, by whom, and under what legal framework resupply can be sustained becomes as practical an issue as missile range. During the Cold War, the JMSDF emphasized anti-submarine and escort capabilities to support the U.S. Navy's rear. Now, in addition to that, the integration of the Japan Coast Guard and the U.S. Coast Guard in peacetime and during crises is being called into question.

The Significance of the Coast Guard's Involvement

A key feature of this exercise is that it is not solely a drill between the JMSDF and the U.S. military. The participation of a large patrol vessel from the Japan Coast Guard is a natural progression considering the potential gray zone situations anticipated in the East China Sea and around the Sakishima Islands. In situations where the intentions of the adversary are unclear, it is more likely that a patrol vessel, rather than an escort ship, will be the first to respond on the scene. The involvement of the U.S. Coast Guard, along with the JMSDF's air units providing support from the rear, can be seen as training that connects maritime order maintenance before armed conflict with military sustainability during crises.

However, this trilateral cooperation has not only advantages but also constraints. The Japan Coast Guard is not a military organization, and its missions and legal authorities differ from those of the JMSDF. Therefore, simply aligning communication and resupply procedures is not sufficient. Decisions must be made regarding who will command at what stage of a crisis, what information will be shared, and which vessels will receive which supplies. If these details are not determined, the supply lines at sea will remain merely on paper.

Small-Scale Training Indicates Significant Changes

Pacific Atlas 26-1 may not make headlines compared to large-scale exercises like Valiant Shield 26. However, its practical value is not insignificant. The fact that a U.S. Coast Guard cutter operated under the tactical command of the U.S. 7th Fleet's destroyer squadron indicates that the boundaries between military branches are becoming considerably blurred in operational contexts.

As the operations of the China Coast Guard and the People's Liberation Army Navy's blue-water deployments become the norm, what Japan needs is not merely an increase in escort ships. It is the ability to seamlessly connect resupply, maintenance, communication, law enforcement, and anti-submarine surveillance. This training can be seen as an examination of that connection.

In the author's view, the true challenge lies not in vertical resupply itself, but in how to connect peacetime law enforcement agencies to sustained military operations in times of crisis without friction.

If equipment is increased while leaving this point ambiguous, the defense of the Nansei Islands may appear strong, but in reality, it could falter at the junction of resupply and authority. What Pacific Atlas 26-1 demonstrated is the necessity of refining that junction from peacetime.