Lt. Col. Matsuda was an officer of the Imperial Japanese Army who was posted in Germany, mainly to learn aeronautics from the German Luftwaffe. In March of 1945, he returned home onboard U-1324, commanded by Capt. Wentzel Ahbe. One other passenger, SS Lt. Col. Spielberger, managed to board the U-Boat before leaving Kiel, Germany, carrying a painting, "The Twelve Knights Led by Brunhilda", believed to be painted by Adolph Hitler (over sixty years later, it was revealed that it was a meaningless painting).

Unlike Spielberger, who rarely left his quarters, Matsuda openly socialized with Ahbe and his crew. He even taught the German crew shogi (Japanese chess), which he played with them during his journey to the Japanese base in Batavia, located in the South China Sea.

For the most part, U-1324 was lucky, avoiding enemy patrols, and even torpedoing an enemy tanker in the Indian Ocean. However, the ship ran into a U.S. Navy patrol near Batavia, and was depth-charged into a dive bow-first into the floor of the ocean. With escape impossible and not wishing the disgrace of capture, Matsuda committed seppuku (ritual suicide).

(source: Absolute Anime)