The I-401 was a Japanese submarine during World War II, notable for its advanced design and capabilities. Launched in 1943, it was part of the I-400 class, which was the largest submarine class of its time. The I-401 was equipped to carry and launch Kō-hyōteki (special attack) aircraft, allowing it to conduct unique missions against enemy targets. The submarine was primarily used for reconnaissance and offensive operations in the Pacific Theater. After the war, the I-401 was captured by the United States and later scuttled in 1946. Its design influenced future submarine technology and tactics in naval warfare.