KOBE, Japan — Mitsubishi Heavy Industries (MHI) launched the JS Shogei (SS-519) at its Kobe shipyard on October 8, 2026. The vessel is the seventh Taigei-class diesel-electric attack submarine (SSK) constructed for the Japan Maritime Self-Defense Force (JMSDF).
Built at a contract cost of ¥80.5 billion (~$509 million), the 3,000-tonne submarine features advanced high-capacity lithium-ion (Li-ion) battery energy storage, floating machinery mounts, and an upgraded acoustic sonar suite. Following outfitting and sea trials, JS Shogei is scheduled for formal commissioning into JMSDF operational service in March 2028.
TECHNICAL SPECIFICATIONS: JAPAN MARITIME SELF-DEFENSE FORCE TAIGEI-CLASS SSK (JS SHOGEI / SS-519) 
* Shipbuilder & Yard: Mitsubishi Heavy Industries (MHI), Kobe Shipyard, Hyogo Prefecture
* Operating Arm: Japan Maritime Self-Defense Force (JMSDF)
* Program Status: 7th Taigei-class hull launched; scheduled commissioning in March 2028
* Unit Procurement Cost: ¥80.5 billion (~$509 million USD)
* Platform Dimensions & Displacement:
* Standard Displacement: 3,000 tonnes
* Length: 84.0 meters
* Beam: 9.1 meters
* Hull Depth: 10.4 meters
* Crew Complement: 70 officers and enlisted personnel
* Propulsion & Power Architecture:
* Diesel Generators: 2× Kawasaki 12V 25/31 high-output diesel engines (high-rate recharging during snorkeling)
* Energy Storage: Submerged Lithium-ion (Li-ion) battery bank (replaces legacy lead-acid and Stirling AIP)
* Output: Single shaft driving electric propulsion motor (4,413 kW / 6,000 hp)
* Submerged Performance: Reported maximum speed of 20 knots (~37 km/h)
* Acoustic Quietening & Structural Engineering:
* Floating Machinery Mounts: Sound-dampening shock mitigation mounts to decouple machinery vibrations from seawater
* Stealth Architecture: Sound-absorbing acoustic tile coatings and non-hull-penetrating optronic masts
* Sensor Suite & Combat Management:
* Integrated Sonar: ZQQ-8 suite (conformal bow array, flank arrays, and fiber-optic towed array)
* Information Processing: OYX-1 command and processing architecture
* Fire Control & Visual Display: ZQX-12 tactical display system
* Electronic Warfare & Navigation: NZLR-2 ESM suite and ZPS-6H navigation radar
* Armament & Firepower:
* Torpedo Tubes: 6× 533 mm bow tubes
* Ordnance Portfolio: Type 18 heavyweight torpedoes and UGM-84L Harpoon Block II anti-ship missiles
* Self-Defense: Advanced torpedo countermeasures (TCM) suite
