Japanese commerce raiders Aikoku Maru and Hōkoku Maru
The Japanese raiders in the Indian Ocean were vessels of the Imperial Japanese Navy (IJN) during the Second World War for commerce raiding against Allied ships. Possessing a powerful fleet of warships, prior to the start of the war, the IJN had planned to fight a war of fleet actions and delegated few resources to raiding merchant vessels.
Source: Wikipedia — Japanese commerce raiders Aikoku Maru and Hōkoku Maru (CC BY-SA 4.0)