The JS Kaga, one of two Japanese helicopter destroyers, completed its first round of modifications to accommodate F-35B Lightning II stealth fighters on March 29, 2024.

The JS Kaga, one of two Japanese helicopter destroyers, completed its first round of modifications to accommodate F-35B Lightning II stealth fighters on March 29, 2024. (Japan Maritime Self-Defense Force)

TOKYO — Japan has finished phase one of a plan to turn another of its largest warships into a carrier of fifth-generation stealth fighters, according to the Japanese navy.

Upgrades designed to accommodate U.S.-made F-35B Lightning IIs aboard the helicopter destroyer JS Kaga were finished March 29, the Japan Maritime Self-Defense Force said Saturday in a post on X, formerly Twitter. Modifications began in 2022 and the Kaga underwent sea trials in November absent F-35Bs.

The B variant is capable of short takeoffs and vertical landings, ideal for Japan’s 814-foot helicopter destroyers. The U.S. Nimitz-class carriers, in comparison, are 1,092 feet long.

Changes to the Kaga included painting its flight deck with heat-resistant material that tolerates the F-35B’s vectored-thrust engines, installing lights for nighttime operations and reshaping the flight deck’s bow from a trapezoid to a rectangular shape, a Maritime Self-Defense spokesman told Stars and Stripes by phone Tuesday.

Some Japanese government spokespeople may speak to the media only on condition of anonymity.

The modifications follow a similar retrofit three years ago to the Kaga’s sister ship, JS Izumo, to accommodate the fighters.

In October 2021, a pair of U.S. Marine Corps F-35Bs took off from the Izumo to test its improvements and became the first fighters to fly from a Japanese carrier since World War II.

F-35B test flights are being considered for the Kaga this fiscal year, the spokesman told Stars and Stripes. Japan’s fiscal year begins in April.

The Izumo’s second and final round of modifications are scheduled to begin this fiscal year; the Kaga’s final round will begin after the Izumo’s are completed, the spokesman said. No completion date for the modifications has been set.

Japan has planned to upgrade the ships for years. The country’s Defense Ministry views the ability to launch and recover F-35Bs at sea as “necessary in order to be fully prepared to protect Japan’s seas and skies, including the vast Pacific Ocean, while ensuring safety of the self-defense forces personnel,” according to a 2022 white paper.

In 2020, the Defense Ministry asked for about $795 million to purchase six F-35Bs from the United States and about $29 million for upgrades to the Izumo. In 2021, the ministry sought another $474 million for four more F-35Bs and $61 million for upgrades for the carriers’ flight decks.

Japan has since purchased 42 F-35Bs. The first six are expected to be delivered and based at the Japan Air Self-Defense Force’s Nyutabaru base in Miyazaki prefecture by the end of this fiscal year, The Japan Times reported Tuesday.

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Hana Kusumoto is a reporter/translator who has been covering local authorities in Japan since 2002. She was born in Nagoya, Japan, and lived in Australia and Illinois growing up. She holds a journalism degree from Boston University and previously worked for the Christian Science Monitor’s Tokyo bureau.
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Alex Wilson covers the U.S. Navy and other services from Yokosuka Naval Base, Japan. Originally from Knoxville, Tenn., he holds a journalism degree from the University of North Florida. He previously covered crime and the military in Key West, Fla., and business in Jacksonville, Fla.

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