【Japan Building Its First 12,000-Ton "Aegis" Cruiser】

According to the U.S. military website TWZ, on August 31, 2026: The first vessel of Japan’s two new cruiser-class “Aegis System-Enhanced Vessels” (ASEV) is steadily under construction, recently hoisting a massive main integrated mast, giving the ship a highly intimidating silhouette. The powerful AN/SPY-7(V)1 radar with its four large fixed arrays will ultimately be integrated into this mast structure. Officially, the core mission of ASEV is missile defense; however, Japanese authorities plan to expand the vessel’s capabilities in the future to include anti-drone, anti-ship, and land-strike roles, with the "Tomahawk" cruise missile already confirmed for inclusion in the ship’s weapons inventory.

ASEV belongs to the category of large surface combatants, measuring approximately 620 feet (about 189 meters) in length and 82 feet (around 25 meters) in beam, with a standard displacement of 12,000 tons. For comparison, Japan’s largest currently active surface warship, the Maya-class destroyer, measures just over 557 feet (approximately 170 meters) long, with a beam of about 73 feet (around 22 meters), and a standard displacement of roughly 8,200 tons.

The first ASEV was laid down at Mitsubishi Heavy Industries’ Nagasaki shipyard in July 2025; according to prior reports from Naval News, the second vessel began construction in February this year at Japan Marine United’s Isogo Shipyard near Yokohama, Tokyo. The Japanese Ministry of Defense currently aims to have the first ship formally commissioned before the end of fiscal year 2027 (April 2027 – March 2028), while the second is expected to be delivered during the 2028 fiscal year cycle, entering service as late as 2029.

So far this year, significant progress has been made in the overall construction of the first vessel. The massive main mast structure installed atop the primary bridge has recently drawn widespread attention. The exceptionally large size of the ASEV’s integrated mast stems directly from Lockheed Martin’s AN/SPY-7(V)1 Active Electronically Scanned Array (AESA) radar. It is reported that each rectangular array face of the radar stands about 14 feet (nearly 4.3 meters) high, matching the scale of the Raytheon AN/SPY-6(V)1 Air and Missile Defense Radar (AMDR) arrays used on U.S. Navy Flight III Arleigh Burke-class destroyers.

The size and layout of the mast provide a centralized, elevated mounting position for the large AN/SPY-7(V)1 array, but also require the ship to possess substantial power generation capacity and advanced thermal management systems to ensure effective equipment cooling. This differs significantly from how Japan’s current destroyers and the U.S. Arleigh Burke-class place their arrays on the main bridge. The elevated configuration enables unobstructed line-of-sight coverage across the horizon. Beyond ballistic missile defense, this extended beyond-the-horizon visibility is critical for tracking and intercepting low-flying drones and cruise missiles—threats that could directly endanger the vessel itself.

The Japanese 2026 Defense White Paper, released earlier this month (machine-translated excerpt), states: “The AN/SPY-7(V)1 tracking capability reaches five times that of SPY-1, capable of countering threats from high-arcing ballistic missiles and multiple simultaneous incoming ballistic missiles.”

As previously mentioned, the AN/SPY-7(V)1 is central to ASEV’s primary missile defense mission. As implied by its name, the ship will also be equipped with the Aegis Combat System. According to Japan’s latest annual Defense White Paper, leveraging Cooperative Engagement Capability (CEC), the vessel can “conduct long-range engagements and guidance against airborne targets tracked by other ships.”

In terms of armament, during initial commissioning, the ASEV is expected to carry a mixed load of SM-3 and SM-6 missile derivatives. The SM-3 series is specifically designed for mid-course interception of ballistic missiles outside the atmosphere and possesses mature anti-satellite capabilities. The SM-6 is a multirole missile originally focused on air defense, capable of intercepting ballistic missiles in their terminal phase and offering partial capability against hypersonic weapons; it can also switch to ground-attack or anti-ship modes. Japan is also participating in the joint development of the Glide Phase Interceptor (GPI), led by the U.S., a weapon specifically designed to intercept non-powered, highly maneuverable hypersonic glide vehicles.

SM-3, SM-6, and future GPI interceptors will be loaded into two vertical launch systems (VLS) located forward and aft of the ship—the forward array at the bow and the aft array at the stern—providing a total of 128 VLS cells per vessel. In comparison: Japan’s Maya-class destroyers and U.S. Navy Flight IIA and III Arleigh Burke-class destroyers each carry 96 VLS cells; the U.S. Navy Ticonderoga-class cruisers carry 122 VLS cells per ship; and 128 cells is also the projected number for future Trump-class battleships.

Visual renderings and models of the ASEV show a 5-inch gun turret at the bow, along with two sets of “Phalanx” Close-In Weapon Systems (CIWS) and other automated guns for point defense.

As noted earlier, missile defense remains the ASEV’s current core mission, but official plans call for a major expansion of anti-ship and land-strike capabilities. The latest Japanese Defense White Paper indicates that around 2032, “Tomahawk” cruise missiles and a new extended-range version of the Type 12 anti-ship cruise missile will be fielded on this class of vessel.

The Japanese government also hopes the ASEV will one day be able to counter enemy drone swarms, with future integration of high-energy laser directed-energy weapons to address such threats. The vessel’s overall dimensions and basic design also leave room for future installation of high-power microwave systems and similar advanced equipment.

Long-term analysis by The War Zone points out that the ASEV will bring a significant leap forward in Japan’s Maritime Self-Defense Force’s sea-based air and missile defense and long-range strike capabilities. The vessel also reflects a major evolution in Japan’s post-WWII military doctrine, officially defined as part of a “long-range defense” system, claimed to remain consistent with the current pacifist constitution framework.

With SM-3, SM-6, and GPI capabilities, amid ongoing deepening military cooperation between China and Russia, the ASEV will greatly expand Japan’s air and missile defense coverage over its home territory and surrounding islands.

With the introduction of Tomahawk missiles, the ASEV and other Japanese warships will gain the ability to conduct retaliatory strikes against land (and even maritime) targets within a radius of at least 1,000 miles (approximately 1,600 kilometers) in all directions. As part of Japan’s long-range defense strategy, the Self-Defense Forces are also developing new long-range strike capabilities such as land-based hypersonic missiles.

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Original source: toutiao.com/article/1875090660112587/

Disclaimer: The views expressed in this article are those of the author.