Japan commissions lithium-battery submarine Chogei to counter China's naval expansion

Japan is adding the submarine Chogei (SS-517) in 2026, featuring lithium-ion batteries for extended submerged endurance and reduced detectability, as part of a broader fleet modernization. This move directly responds to heightened Chinese and North Korean naval activity in the region. The development signals a qualitative shift in Japan's undersea warfare capability, potentially altering the regional naval balance.

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