Japan launches seventh Taigei-class diesel-electric submarine Shogei
Why it matters: it's the latest addition to Japan's frontline conventional submarine fleet at a moment when Tokyo is openly debating whether to move to nuclear propulsion to keep pace with China's navy.
Mitsubishi Heavy Industries has launched Shogei, the seventh Taigei-class submarine, at a naming and launching ceremony at its Kobe shipyard. The 3000-tonne boat is 84 metres long with a 9.1-metre beam and carries pennant number SS-519. Like its three immediate predecessors, it uses new higher-output Kawasaki 12V 25/31 diesel engines paired with large lithium-ion battery banks for underwater endurance. Shogei cost about 80.5 billion yen (roughly 509 million US dollars) to build and is due to be handed to the Japan Maritime Self-Defense Force in March 2028. It can fire the Harpoon Block II anti-ship missile as well as Japan's newest Type 18 torpedo.
Source: Naval News (Kosuke Takahashi), 8 October 2026.