World War II Pacific theater battle fought by units of the U.S. Pacific Fleet and Japanese carrier forces as the United States attempted to prevent a Japanese landing at Port Moresby on New Guinea. The Battle of the Coral Sea was the first naval engagement in history in which two fleets fought without opposing surface ships making visual contact.
Following their successful December 7, 1941, attack on Pearl Harbor and early military triumphs, Japanese leaders were reluctant to continue with their original strategy of shifting to a defensive posture. They feared the adverse impact this might exert on their forces’ fighting spirit and believed that it would work to Japan's disadvantage by allowing the Western powers time to regain their strength.
Japanese naval leaders in particular were anxious to occupy the Hawaiian Islands and Australia, the two chief points from which U.S. forces might mount offensive operations. U.S. carriers were operating out of Pearl Harbor, still the headquarters of the U.S. Pacific Fleet. If Japanese forces could take the Hawaiian Islands, it would be virtually impossible for the U.S. Navy to conduct long-range Pacific naval operations. Also, securing the islands to the north and east of Australia—the Solomons, New Caledonia, and Samoa—would enable the Japanese to establish bases to cut the Allied lifeline from the United States to Australia. Japanese long-range bombers would then be able to strike targets in Australia itself, preparatory to an invasion and occupation of that continent.
The Japanese army was not enthusiastic about either proposal. Most of its assets were tied down in China fighting the Guomindang (Kuomintang, Nationalist) Army and garrisoning Manchuria. Invading Australia and occupying even the populated areas would require significant military resources that the army could not spare. The Army Ministry and General Staff in Tokyo therefore advocated holding the gains already achieved in the southern advance and shifting resources to China. The army formally vetoed the navy plan in early April 1942, but, in effect, it was dead by the end of January. Japanese navy leaders hoped, however, that a success either eastward toward Pearl Harbor or southwest toward Australia might overcome army opposition.
Admiral Yamamoto Isoroku, commander-in-chief of the Japanese Combined Fleet, and his staff favored taking Midway Island, 1,100 miles west of Pearl Harbor, as a preliminary step before invading Hawaii. Yamamoto expected this move would provoke a strong U.S. naval reaction, enabling him to set a trap for and destroy the U.S. aircraft carriers. The Japanese naval staff, however, preferred the southeasterly drive to isolate Australia. By the end of March, the Japanese had already advanced from Rabaul into the Solomon Islands and along the northern coast of New Guinea. The Japanese Imperial General Staff searched for a strategy to follow up their successes. Initially, the Naval General Staff favored assaulting Australia, fearing an Allied buildup there could lead to a counteroffensive against the Japanese defensive perimeter. The army rejected an Australian operation because of long distances, insufficient troops, and inadequate transportation. In January 1942, both agreed on a less demanding joint invasion of Lae and Salamaua in New Guinea; the seizure of Tulagi in the Solomons; and the capture of the Australian base of Port Moresby in Papua, New Guinea.
On March 8, 1942, U.S. carriers, sent to beleaguer the Japanese base at Rabaul northeast of New Guinea, interdicted Japanese landing operations at Lae and Salamaua on the Papuan peninsula of eastern New Guinea. Two carrier task forces, one built around the carrier Lexington under Vice Admiral Wilson E. Brown and Rear Admiral Frank Jack Fletcher's task force centered on the carrier Yorktown, sailed into the Gulf of Papua on the opposite side of the peninsula. Together, on the morning of March 10, they sent 104 aircraft across the high Owen Stanley Mountains and surprised Japanese ships discharging troops and supplies at both Lae and Salamaua. The attacking U.S. aircraft sank three Japanese ships, including the armed merchant cruiser Kongo Maru at a cost of only one plane and one aviator lost.
The action caught the Japanese operational commander, Vice Admiral Inouye Shigeyoshi, by surprise and convinced him that conquest of New Guinea would have to be postponed until he could secure fleet carriers for protection. That opportunity came only after the return of the carriers from the Japanese raids into the Indian Ocean.
In early April 1942, the attention of the Imperial Naval General Staff was on southeast operations (seizure of strategic points in New Guinea, New Caledonia, the Fiji Islands, and Samoa) to isolate Australia. However, the April 1942 (Doolittle) raid on Tokyo refocused their attention on the destruction of the U.S. carriers and forced an earlier date for the Tulagi and Port Moresby operations, with the New Caledonia, Fiji, and Samoa operations to follow after Midway.
Admiral Inouye, commanding the Fourth Fleet and Operation MO, as it was designated, broke his forces into five groups: two invasion groups to land army and naval forces at Tulagi and Port Moresby; a support group to establish a seaplane base in the Louisiade Archipelago off New Guinea; a small covering group with the light carrier Shoho; and the main striking force of two fleet carriers, Shōkaku and Zuikaku, plus escorts. This strike force, commanded by Vice Admiral Takagi Takeo, was to support both landings and to protect the entire force from U.S. carriers.
At Pearl Harbor, Admiral Chester W. Nimitz, commander of the U.S. Pacific Fleet, determined from intercepts that the Japanese would probably attack Port Moresby on May 3. On April 29, he ordered Rear Admiral Frank Jack Fletcher, commanding the Yorktown group, to operate in the vicinity of the Coral Sea beginning on May 1. Rear Admiral Aubrey Fitch's Lexington group and the U.S. Southwest Pacific Command's combined naval force of two Australian cruisers, the U.S. heavy cruiser Chicago, and two U.S. destroyers under Rear Admiral John Crace, of the Royal Navy, were also placed under Fletcher's tactical command. The two carrier groups and Crace's force formed Task Force 17 when they rendezvoused on May 1 some 250 miles off the New Hebrides. While the Lexington’s group refueled, Fletcher sailed the Yorktown’s group north on May 2 to reconnoiter, having received reports of approaching Japanese naval forces.
On May 3, the Japanese Tulagi invasion group began landing forces without opposition. Learning of the landings, Fletcher decided to strike Tulagi the next morning without waiting for the Lexington to join him. He sent his fleet oiler and its escorts to inform Fitch and Crace of his change of plans and to order them to join him 300 miles south of Guadalcanal on May 5. The Yorktown then closed on Tulagi undetected on May 4 and launched three air strikes that met little resistance. Admiral Takagi's carrier striking force had been delayed and was nowhere near Tulagi. Inexperienced as they were, the U.S. attackers were ineffective, only damaging a destroyer to the point that it had to beached and sinking three small minesweepers and four landing barges. The planes also shot up some grounded aircraft. However, even this small success was enough to send the remainder of the Tulagi invasion force steaming back to Rabaul.
Withdrawing southward, Fletcher rejoined Fitch and Crace as scheduled on May 5. Task Force 17 then moved northwest, expecting to catch Japanese forces as they emerged from the Jomard Passage into the Coral Sea. Although sightings were made by both sides on May 6, essentially ineffective reconnaissance led to little significant action by either.
Before dawn on May 7, the opposing fleet carriers passed within 70 miles of each other. At dawn, both sides sent out search planes over the Coral Sea. The Japanese sighting of what they thought were a U.S. carrier and cruiser led to the sinking of the destroyer Sims and the inflicting of fatal damage on the oiler Neosho. At about the same time, a U.S. scout aircraft reported two Japanese carriers north of the Louisiades. After the Lexington and Yorktown launched their aircraft, Fletcher discovered that his ships had been sighted by a Japanese scout plane. The action prompted by the U.S. sighting turned out to be a wild goose chase, but the Lexington and Yorktown pilots stumbled on the light carrier Shoho and sank it.
Early the next morning, the two carrier forces found each other. The U.S. planes concentrated their attack on the fleet carrier Shōkaku but hit it with just three bombs, causing only modest damage. The fleet carrier Zuikaku escaped attack by hiding in a rainsquall. The Shōkaku’s damage was sufficient to prevent launch-and-recovery operations, however; and when the Americans withdrew, it turned north toward Japan.
Meanwhile, planes from the Shōkaku and Zuikaku found the Lexington and Yorktown. Diving out of the sun, torpedo planes hit the Lexington twice on the port side, and dive-bombers scored two minor hits. The Yorktown was hit by only one bomb, which did no major damage. Confident they had sunk the Saratoga, the Lexington’s sister ship, and the Yorktown, the Japanese pilots withdrew. Neither ship sank, however, until gasoline vapors aboard the Lexington reignited fires that eventually became uncontrollable; as a result, it was abandoned, with Fletcher forced to order it scuttled by torpedoes from a nearby destroyer.
Both sides hailed their achievements in the Coral Sea and scored themselves a win. Tactically, the Japanese came out ahead. The United States was hurt most by the loss of the Lexington, one of its largest carriers, whereas Japan lost only the light carrier Shoho and suffered moderate damage to the large carrier Shōkaku. Although Japan scored a tactical victory, the United States had finally blunted a Japanese offensive thrust, preventing the occupation of Port Moresby and thus winning the strategic victory. In addition, significant losses in aircraft, aircrew, and repairs to the Shōkaku prevented both Japanese carriers from taking part in the critical Battle of Midway a month later.
See also Aircraft Carriers; Fletcher, Frank Jack; Halsey, William Frederick Jr.; Inouye (Inoue) Shigeyoshi; King, Ernest Joseph; Midway, Battle of; Nimitz, Chester William; Takagi Takeo; Yamamoto Isoroku.
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