Taigei-class

The development of this attack submarine class originated from a series of research initiatives launched in 2004 to identify requirements for a successor to the Sōryū class. Initial studies utilized simulation technologies to optimize design efficiency for platforms intended to operate from the 2020s onward. Subsequent technical evaluations conducted through 2018 focused on enhancing dive speed, stealth, and underwater sustainability. The first vessel was laid down in 2018 and entered service in 2022.

This class is a diesel-electric attack platform characterized by the integration of large-scale lithium-ion battery arrays, which facilitate greater underwater endurance and higher speeds than traditional configurations. The internal architecture employs a floating floor structure, utilizing a buffering mechanism to prevent internal vibrations from being transmitted into the water while providing shock resistance. The hull design is specifically engineered to reduce fluid noise and low-frequency interference generated by the interaction between the hull and the propeller. Operational sensors include a surface and low-level air search radar and a specialized sonar suite designed for improved detection and tracking in complex marine environments. The primary armament consists of torpedo tubes configured for heavyweight torpedoes and anti-ship missiles.

These submarines are deployed by the Japan Maritime Self-Defense Force to conduct attack and monitoring operations. The lead vessel of the class functions as a dedicated test platform, a role intended to accelerate research and development while ensuring that commissioned units remain available for active service. Operational vessels are currently based out of Yokosuka and Kure.