Japanese raiders in the Indian Ocean

The Japanese raiders in the Indian Ocean were those vessels used by the Imperial Japanese Navy (IJN) during the Second World War to pursue its war on Allied commerce in that theatre. Possessing a powerful fleet of warships, prior to the start of World War II, the IJN had strategically planned to fight a war of fleet actions, and as a consequence delegated few resources to raiding merchant vessels. Nevertheless, in 1940, two passenger-cargo vessels – Aikoku Maru and Hōkoku Maru – of the Osaka Shipping Line were requisitioned for conversion to armed merchant cruisers (AMC)s, in anticipation of the likely thrust southward by the Japanese. These vessels were subsequently used as merchant raiders attacking Allied commercial shipping along vital sea lanes of communication between Australia and the Middle East. Using their comprehensive armament and speed to their advantage, the raiders experienced a brief period of success. Japanese raiding in the Indian Ocean largely ceased by the end of 1942 after an action with a Dutch vessel, the Ondina and a Royal Indian Navy corvette, HMIS Bengal in which the Hōkoku Maru was sunk.