Japan Responds to Trump’s Overture... Naval Power in Focus [Yang Nakkyu’s Defence Club]

Japan Reviews Legal Grounds for Hormuz Warship Deployment Request

A Maritime Power with Izumo-class Ships Including Kaga and Izumo

U.S. President Donald Trump has requested that allied nations, including South Korea, dispatch warships to the Strait of Hormuz. Against this backdrop, Japanese Prime Minister Sanae Takaichi visited the White House. As a result, Prime Minister Takaichi is now in a position where she must state her stance on troop deployment directly in front of President Trump. Japan's decision is drawing attention, as it will inevitably affect South Korea's response as well.

Prime Minister Takaichi has so far stated that "the necessary response measures are currently under review." This indicates that Japan is even considering the legal grounds in preparation for a possible request from the U.S. for Self-Defense Forces deployment during the U.S.-Japan summit. In 2019, during the administration of Shinzo Abe, Japan received a request from the United States to join the coalition to protect the Strait of Hormuz. This highlights Japan's recognition as a naval powerhouse.

Japan Maritime Self-Defense Force destroyers Kaga (184) and Izumo. Photo by Japan Maritime Self-Defense Force

Japan has long required a strong naval force due to geopolitical factors. The country has five major ports: Kobe, Osaka, Nagoya, Yokohama, and Tokyo. Through these five ports, Japan aimed to dominate economic activity in the so-called "Mediterranean of Northeast Asia," solidifying its regional hegemony by building a massive naval force under the U.S. nuclear umbrella.

Even before World War I, Japan was equipping warships with fighter aircraft. On September 5, 1914, during the height of World War I, Japan launched two biplanes from its first aircraft carrier, Wakamiya-maru. The target was Qingdao, China—marking Japan's first combat air strike. Over two months, Japanese biplanes flew 49 sorties and dropped 190 bombs from the sky.

Japan's Use of Aircraft Carriers After World War I

After World War I, Japan leveraged its know-how in operating seaplane carriers to focus on constructing deck-based aircraft carriers. Currently, Japan possesses as many as four escort flotillas, each comprised of eight destroyers (in Japanese, called escort ships): one Myoko-class Aegis destroyer (7,500-ton class) and seven general-purpose destroyers (4,000 to 5,000-ton class).

Each escort flotilla essentially consists of one helicopter-carrying escort ship (DDH), which is virtually a light aircraft carrier, five general-purpose escort ships (DD), and two Aegis destroyers (DDG), totaling eight vessels. The combat strength of one escort flotilla is comparable to a U.S. 7th Fleet carrier strike group without its aircraft carrier. If Japan amends its constitution, it could effectively establish four carrier strike groups. This forms the core combat capability for Japan's "1,000-nautical-mile shield" strategy—defending Japan from waters 1,000 nautical miles (1,852 km) from the archipelago.

Reusing Names of Prestigious Aircraft Carriers

Among the escort flotillas, the most notable vessels are the Izumo-class ships, Kaga and Izumo, each weighing 24,000 tons. Japan Marine United (JMU) has converted them at the Isogo Shipyard in Yokohama to operate F-35B fighter jets, making them light aircraft carriers. Aircraft carriers are classified by size: light carriers (10,000 to 30,000 tons), medium carriers (40,000 to 70,000 tons), and large carriers (80,000 to 100,000 tons).

The Kaga has a maximum displacement of 27,000 tons, a length of 248 meters, and a width of 38 meters—making it the largest vessel in the Japan Maritime Self-Defense Force. The deck spans the entire length of the ship, with a separate hangar that can accommodate up to 14 helicopters. The Kaga serves as the maritime command for joint operations of the Ground, Maritime, and Air Self-Defense Forces. It can also transport Marines from the Amphibious Rapid Deployment Brigade using MV-22 Osprey vertical takeoff and landing transport aircraft.

The name Kaga is identical to that of an aircraft carrier from Japan's imperial era, which spearheaded invasions of China. The original Kaga first saw combat in the 1932 Shanghai Incident, a military clash between China and Japan. This was the first time in naval history that an aircraft carrier participated in combat. At the time, the Chinese called the Kaga the "Devil Ship." This is why Chinese state media have strongly criticized the Kaga's deployment as "the return of the Devil Ship." The Kaga also took part in Japan's 1941 attack on Pearl Harbor and was sunk by U.S. bombers during the 1942 Battle of Midway.

Izumo Has Already Conducted Joint Maritime Drills with the U.S.

The other light aircraft carrier is the Izumo. In 2017, it was deployed to the South China Sea for the first time. During that mission, the Izumo made port calls in Singapore, Indonesia, the Philippines, and Sri Lanka, and later conducted joint maritime exercises in the Indian Ocean with the U.S. and Indian navies. The name Izumo is the same as that of a cruiser built by Japan with indemnities received after its victory over China in the First Sino-Japanese War. The original Izumo was also the flagship of the Japanese fleet that attacked Shanghai in 1937. The Izumo has a displacement of 19,950 tons, a length of 248 meters, and a width of 38 meters.

The main reason neighboring countries fear these light aircraft carriers is their ability to carry the U.S. F-35B stealth fighter jet with vertical takeoff and landing capabilities. The F-35B is 15.6 meters long, has a wingspan of 10.7 meters, a height of 4.36 meters, a maximum speed of Mach 1.6, and can carry up to 6.8 tons of weapons. Its internal weapons bay can hold two air-to-air missiles and two 1,000-pound Joint Direct Attack Munitions (JDAMs). The combat radius is 833 km. In addition to its stealth capabilities, the F-35B can share information with Aegis destroyers during combat. Japan's Ministry of Defense plans to establish a "temporary F-35B squadron" at Nittawara Base.

Decks Modified to Accommodate U.S. F-35Bs

The Kaga and Izumo have already been constructed with consideration for F-35B operations, including hangars, elevators, and flight decks. Modifications are in their final stages to strengthen the flight deck to withstand the weight of the F-35B, install heat-resistant decks for the intense exhaust from vertical takeoff and landing, and add flight guidance systems.

A military official stated, "Currently, only eight countries—namely, the U.S., China, Russia, the UK, France, Italy, India, and Thailand—operate aircraft carriers. With the U.S. Navy's strength weakening, the U.S. may have no choice but to request assistance from these countries to secure the Strait of Hormuz."

This content was produced with the assistance of AI translation services.