China has lately been resorting to defiant and audacious acts like claiming its territorial rights over waters around artificial island it has built in the Spratly Islands in the South China Sea and unilaterally designating an air defense identification zone in the East China Sea.

While these acts are visible to all, the real front battle line lies deep in the sea where submarines are principal players. This article attempts to provide in-depth descriptions of the real picture of submarines of the Maritime Self-Defense Force and their roles, as little has so far been made known about them.

During the 1998 Rim of the Pacific Exercise off the coast of Hawaii, Adm. Archie Clemens, commander in chief of the U.S. Pacific Fleet, was dumbfounded as a monitor screen showed that eight vessels of his fleet were "attacked and sunk" one after another by a single MSDF submarine.