Japan Commissions New Submarine JS Chōgei

The Japan Maritime Self-Defense Force (JMSDF) has formally commissioned its fifth Taigei-class submarine, the JS Chōgei, on March 10th. The vessel, built by Mitsubishi Heavy Industries, represents a significant enhancement to Japan’s underwater capabilities.

Delivery and Deployment

Construction of the JS Chōgei began in 2022, with its launch taking place in 2024. The submarine was handed over to the JMSDF at Mitsubishi Heavy Industries’ Kobe shipyard this year. Following commissioning, the vessel was assigned to Submarine Division 2, under Submarine Flotilla 2.

The JS Chōgei will be homeported at Yokosuka Naval Base in Kanagawa Prefecture. Its primary missions will include anti-surface and anti-submarine warfare, as well as intelligence, surveillance, and reconnaissance operations. The submarine is also expected to patrol the strategically important Miyako Strait.

Design and Program Background

The Taigei-class program originated in 2004 as a successor to the Soryu-class submarines, which entered service in 2009. Construction of the new class commenced in 2012, prioritizing improved stealth and detection capabilities.

The JS Chōgei measures approximately 275 feet in length, with a beam of nearly 30 feet and a draft of around 34 feet. It displaces roughly 3,307 US tons and has a crew complement of around 70 personnel. A dedicated accommodation space for female personnel has been incorporated, reflecting ongoing modernization within the JMSDF.

The submarine’s name, “Chōgei,” meaning “long whale,” continues a naming convention for vessels in this class, symbolizing both size and stealth.

Advanced Technology and Systems

Taigei-class submarines utilize a diesel-electric propulsion system generating approximately 6,000 horsepower. They are equipped with lithium-ion batteries, offering extended underwater endurance and improved efficiency compared to traditional lead-acid batteries.

The JS Chōgei features advanced sonar technology, including the ZQQ-8 sonar suite, and a modern combat management system integrating sensors, command functions, and weapon control. A redesigned snorkel system and non-penetrating optronic masts further enhance stealth and situational awareness.

Weapons Capabilities

The Taigei-class submarines are armed with heavyweight torpedoes and anti-ship missiles, including the UGM-84L Harpoon Block II, which has a range of about 154 miles. Reports indicate potential future capability to deploy hypersonic weapons, such as a Hyper Velocity Gliding Projectile, though this is still under development.

Future Outlook

Japan plans to construct a total of 10 Taigei-class submarines by 2031, with additional units currently under construction. This growing fleet is expected to play a crucial role in monitoring increased naval activity in the region and serve as a key deterrent force in the Western Pacific.