U.S. to host Japanese Destroyer Chokai for Tomahawk one-year training and modernization.

The U.S. Navy will host Japan’s Aegis destroyer JS Chokai for a yearlong training and modernization program to integrate Tomahawk missiles. The move highlights closer U.S.-Japan military cooperation and Japan’s shift toward long-range strike capability.

Japan’s Ministry of Defense, on 29 September 2025, announced on its X account that the Aegis destroyer JS Chokai has completed a dummy Tomahawk loading drill at Yokosuka and is departing for a yearlong period of modifications and crew training in the United States. The deployment marks the first practical step in putting U.S.-made Tomahawk land-attack cruise missiles to sea with the Japan Maritime Self-Defense Force and sets the template for how the wider fleet will absorb a new long-range strike mission. For Tokyo, this is not a technology trial but an operational pivot. The ship will return in 2026 with a certified crew, an updated combat system, and magazines able to carry theater-range precision weapons that were previously absent from Japanese surface combatants.
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JS Chokai departs Japan for U.S. shipyard modifications and crew training to integrate Tomahawk cruise missiles, marking the first step in Japan’s new counterstrike capability (Picture source: Japanese Ministry of Defense).

Chokai is the fourth unit of the Kongō class, a heavy Aegis destroyer derived from early Arleigh Burke designs and built around air and missile defense. At roughly 9,000 to 9,500 tons full load, four LM2500 gas turbines drive the ship to around 30 knots, giving it the speed to screen carrier and amphibious groups. The sensor suite is anchored by the AN/SPY-1D phased-array radar tied to an Aegis Baseline 5 family combat system that has been progressively modernized for ballistic missile defense duties. The hull carries 90 strike-length Mk 41 vertical launch cells split between fore and aft modules. A typical defensive load has mixed SM-2 area defense missiles, SM-3 interceptors for exo-atmospheric shots, and RUM-139 VL-ASROC for anti-submarine engagements. The destroyer supplements that battery with a 127 mm main gun, two Phalanx close-in weapons, Harpoon anti-ship missiles, and triple torpedo tubes. A flight deck supports helicopter operations even though the class lacks a full hangar.

Those existing strike-length Mk 41 cells are the key to rapid integration. The launcher architecture already fits Tomahawk, which means the yard period focuses on software, safety cases, handling procedures, and mission-planning pathways rather than major structural work. The combat system will be updated to accept Tomahawk fire control, while deck crews complete certification in crane operations, canister handling, and safe strike-down into the launcher uptake. The training syllabus in the United States will also certify a Japanese strike team in targeting, route planning, and in-flight retasking using Tomahawk’s two-way datalink. Japan is acquiring the latest Block V variant, which retains the 1,000-mile-class range and GPS-INS guidance with terrain and scene matching, while opening a growth path to Maritime Strike Tomahawk that can engage moving warships.

Chokai’s primary role has been to serve as a high-end air and missile defense escort, protecting task groups and Japanese territory from cruise and ballistic threats. With Tomahawks embarked, the same hull becomes a distributed fires node that can hold airbases, logistics hubs, and missile batteries at risk from well outside most coastal anti-ship envelopes. The SPY-1D picture and Aegis command-and-decision enable coordinated salvos cued by national and allied intelligence, surveillance, and reconnaissance. Every Tomahawk canister occupies a vertical launch cell that might otherwise carry SM-2, SM-3, or ASROC. Japanese commanders will likely adopt mission-tailored loadouts, surging strike weapons for crisis patrols while preserving heavier defensive inventories during routine ballistic missile defense duty. The training period is designed to teach the crew how to swing between roles without losing tempo, including rapid rearmament and joint deconfliction procedures.

Chokai’s conversion is the first hardware manifestation of Japan’s counterstrike concept adopted in 2022 alongside a multiyear push toward 2 percent of GDP in defense spending. Fielding Tomahawk fills a near-term gap while indigenous long-range missiles are produced at scale and gives policymakers credible options short of escalation. In Northeast Asia, where North Korea’s missile testing is routine and China is expanding anti-access networks around Taiwan and the Ryukyus, putting theater-range conventional strike on a surface combatant raises deterrence by complicating adversary planning. It also deepens operational interdependence with the U.S. Navy on targeting, training, and sustainment. With Chokai acting as the pathfinder, follow-on work on other Kongō, Atago, and Maya destroyers would quickly turn Japan’s Aegis force from a primarily defensive shield into a fleet that can both protect and impose outcomes at range, a message carefully calibrated to be heard across the region.