Japan is bolstering its submarine fleet strength, introducing some of the most advanced and undetectable vessels to its flotilla to stay ahead of China.

On Monday, Japan’s Ministry of Defense was presented with the Hakugei, the second vessel of the Taigei-class diesel-electric submarines, from Kawasaki Heavy Industries. This submarine is outfitted with lithium-ion batteries, allowing it to stay submerged for extended periods and run silently.

The history of Japan’s submarines is fascinating. During the Pacific War, Japanese submarines were responsible for sinking two US aircraft carriers and damaging several other ships. Japan started the war with 63 ocean-going submarines and grew its fleet to 111 during the war. According to the US Naval Institute, the Imperial Japanese Navy developed the submarine faster than any other country. By World War II’s beginning, Japan possessed one of the world’s most powerful submarine fleets. As part of the attack on Pearl Harbor on December 7, 1941, five Type A midget submarines were sent to surround Oahu and sink ships. After the war, Japan continued to step up its submarine development.