Peterson, Oscar Vernon, CWT

The battle's strategic background was set by the Japanese plan formulated in early 1942 that saw the country's forces advance south and southeastward from the Bismarcks and Solomons, with the capture of Tulagi in the Solomons and Port Moresby, New Guinea, as immediate objectives. Secondary objectives were the central Pacific island of Nauru and Ocean (Banaba), in the Gilberts chain northeast of the Solomons, for their phosphate resources, essential for Japanese agriculture.

Over 29 April to 4 May, Japanese forces successfully attacked, invaded, and occupied Tulagi, although several of their warships were surprised and sunk or damaged by aircraft from USS Yorktown (CV-5). Alerted to the presence of U.S. carriers, the Japanese Carrier Strike Force advanced toward the Coral Sea with the intention of finding and destroying the Allied naval forces. Beginning on 7 May, the two sides exchanged air strikes over two consecutive days.The resulting maneuvers and clashes between two U.S. Navy task forces and a combined U.S.­Australian cruiser force with the Japanese Carrier Strike Force and supporting units resulted in a Japanese tactical victory. The Japanese Imperial Navy sank USS Lexington (CV-2), USS Sims (DD-409), and USS Neosho (AO-23), and damaged Yorktown. The Japanese only lost one small carrier (Shoho) and suffered damage to a fleet carrier (Shokaku). Allied forces were forced to withdraw from the operational area. However, with their air groups too battered to support a further advance, the Japanese were brought to a standstill. Although the Japanese had managed to capture Tulagi, Port Moresby remained in Allied control. Shokaku had been hit so severely that she could not join the Midway force. Due to losses of pilots and planes, another carrier (Zuikaku) also did not take part in that operation. Thus, Coral Sea reduced Japanese carriers available for Midway by a third. Eminent U.S. Navy historian Samuel Eliot Morison notes that "so many mistakes were made by both sides in this new mode of fighting that it might be called the Battle of Errors; but more were made by the enemy, and he failed to profit by them."