The Japan Maritime Self-Defense Force (JMSDF) has formally inducted its fifth Taigei-class diesel-electric attack submarine, JS Chōgei (SS-517), built by Mitsubishi Heavy Industries. The handover took place at the company’s Kobe shipyard in Hyogo Prefecture, marking the second submarine delivered from this facility under the program. Construction of the vessel began in 2022, followed by its launch in 2024.
The submarine will be stationed at the JMSDF Yokosuka Naval Base in Kanagawa, where it will support missions including anti-surface warfare, anti-submarine operations, and intelligence, surveillance, and reconnaissance. It is also expected to conduct patrols in key strategic areas such as the Miyako Strait, a vital maritime corridor between Japan, China, and Taiwan.
The Taigei-class program, initiated in 2004 as a successor to the Sōryū-class submarines introduced in 2009, incorporates enhanced structural design, advanced detection systems, and modernized power architecture. Each submarine measures 84 meters in length with a 9-meter beam and accommodates a crew of around 40 personnel.
Powered by two Kawasaki diesel engines paired with lithium-ion batteries instead of traditional lead-acid systems, the platform delivers approximately 6,000 horsepower for extended endurance. It is equipped with heavyweight torpedoes and anti-ship missiles, with potential capability to deploy advanced systems such as hypersonic gliding projectiles. With a displacement of 3,000 tonnes and a top speed of 20 knots, the Taigei-class represents a significant evolution in Japan’s undersea capabilities. Tokyo plans to induct a total of 10 submarines under this program by 2031.
