Battle of The Coral Sea

Before the Battle of the Coral Sea broke out on May 4th, 1942, Allied forces in the Pacific Theater of War had suffered a blistering string of losses as Japan pushed for control of the western Pacific basin.

British forces had suffered crushing defeats in Hong Kong, Malaya, Borneo and Singapore, while Australian forces had been defeated at the vital resupply port of Rabaul. During March of that same year, Dutch forces were overwhelmed at Sumatra and Java, handing critical oilfields to the Japanese, followed by the Allies’ humiliating rout in the Philippines in April, when MacArthur’s sudden retreat from the island nation forced 75,000 Filipino and American troops into brutal Japanese prison camps.

According to the Japanese commander of South Pacific naval operations, Admiral Inoue Shigeyoshi, Japan’s objective by early May was to capture the large airfield at Port Moresby on the southern peninsula of New Guinea—an important expansion aspiration to Japan’s existing defensive perimeter, which would prevent Allied bombers from attacking Japanese strongholds at Rabaul on New Britain or Truk in the Carolines.

A New Era in Naval Engagement

Unknown to Japanese military leaders, American codebreakers had just broken Japan’s main operational cipher, JN-25b, allowing Allied carriers Lexington and Yorktown to intercept the Japanese strike force on May the 4th, beginning a four-day battle which was completely fought from the air. Considered the first modern naval battle in military history, as well as the first carrier-on-carrier engagement, wherein neither carrier group fired directly upon enemy ships, on May the 7th, aircraft from the Lexington and Yorktown sank the Japanese carrier Shoho, before Japanese fighters severely damaged the Lexington, taking the lives of 216 crewmen and forcing the Allies to abandon and scuttle the ship.

A day later, Allied fighters sank the Japanese light carrier Shokaku, while inflicting heavy damage to Japan’s larger carrier Zuikaku, which forced Japan into a hasty retreat. While the battle lacked a decisive winner, the Allies successfully blocked Japan’s capture of Port Moresby, and while Japan would eventually occupy the Solomon Islands, their loss of carriers and some 70 warplanes and experienced fighter pilots shifted their strategy from offense to defense, making the Battle of the Coral Sea, a turning point moment in the war for the Pacific.