The Imperial Japanese Army supported the idea of taking Port Moresby and in April 1942, with the Japanese Navy, developed a plan for the attack that was titled "Operation Mo". The plan also included the seizure of Tulagi, a small island in the southern Solomon Islands, where a seaplane base would be set up for potential air operations against Allied territories and forces in the South Pacific. Although Japanese Admiral Isoroku Yamamoto—commander of the Combined Fleet—was concurrently planning an operation that he hoped would lure the U.S. Pacific Fleet into a decisive showdown in the central Pacific, he detached some of his large warships to support the "Mo" operation and placed Inoue in charge of the naval portion of the operation.