The Battle of Coral Sea
Just like the Axis forces in Europe, the Japanese were quite successful in the Far East. By the beginning of May 1942, they controlled Malaya, Burma, Philippines and the Dutch East Indies and suffered far lower casualties than expected. However, the Japanese officers were not sure what to do next. Some supported a continuation of territorial expansion in the Far East, while some wanted to strike the final blow to the American aircraft carriers in the region and eliminate the American threat. The commander of Japan's Combined Fleet, Isoroku Yamamoto who supported the latter group proposed an attack on the Midway atoll to force the US Navy into a decisive battle which he thought Japan would win. The Japanese high command, however, ordered an attack on Port Moresby in southeastern New Guinea and Tulagi in the Solomon Islands in order to isolate Australia and cut the supply lines between Australia and the United States as well as to be able to use New Guinea as a base to attack Samoa and Fiji. On May 5, Yamamoto was given a green light for the attack on the Midway Island in early June. Meanwhile, however, the Japanese fleet was already fighting with the American Navy in the Coral Sea.
The Americans knew about the Japanese plan to capture Port Moresby and Tulagi thanks to the intelligence information and decided that an eventual Japanese success would leave Australia too vulnerable. Chester Nimitz, the commander of Allied forces in the Pacific and Douglas MacArthur, the commander of the U.S. Army Forces Far East agreed that they must prevent the Japanese from capturing Port Moresby. From the information they received from the broken Japanese naval codes, they knew that the Japanese Navy will have to cross the Coral Sea. Since the USS Saratoga aircraft carrier (it was damaged in early 1942 by a deep-running torpedo) was still being repaired and the other two carriers Enterprise and Hornet would need at least five days to prepare for the battle, Nimitz ordered carriers Lexington and Yorktown to intercept the Japanese fleet. The command over the forces was entrusted to Frank J. Fletcher who was aboard the Yorktown. Nimitz also gave Fletcher free hands in developing the strategy to defeat the enemy fleet.
Fletcher reached the Coral Sea before the enemy fleet, however, it was too late to prevent the fall of Tulagi. On May 3, Fletcher was informed that the island was captured by the Japanese. Early in the morning on May 4, he ordered his pilots to attack the Japanese ships at Tulagi. By the end of the day, they severely damaged one destroyer, sank two minesweepers and four landing barges but failed to inflict any serious damage to the enemy fleet.
The next day, Fletcher rejoined Lexington and Australian cruisers which were commanded by Rear Admiral John Gregory Grace and prepared for an assault on the Japanese fleet which started to enter the Coral Sea. On May 6, Fletcher decided to attack the Japanese fleet that was expected to enter the Jomard Channel on May 7 or 8. However, the Japanese were by now aware that there are American aircraft carriers are in the area and early in May 7, the American positions were found by the Japanese spotter plains. The Japanese returned with bomber planes and sunk the destroyer Sims and severely damaged oil tanker Neosho. They failed, however, to hit the Fletcher's carrier Yorktown. Later in the same day, the Japanese bombers attacked the Australian cruisers but Fletcher moved his carrier away on time. The Australian fleet took another aerial attack that day when it was bombed by the American aircraft mistaking it for the Japanese fleet.
Early in the morning of May 7, three spotter planes from Yorktown reported that they have located the Japanese carriers. But what they have located were not carriers but the Support Group with two light cruisers. The planes from Lexington, however, did spot the Japanese carrier Shoho and sank it before noon. The Japanese Admiral Takeo Takagi answered with night attack which, however, failed. In addition, the Japanese admiral lost 21 of his best pilots who failed to return.
On May 8, the American bombers attacked the Japanese carrier Shokaku and put it out of action because the carrier could not launch any planes due to the damage on the flight deck. Shokaku was attacked for the second time later that day but it managed to stay on the surface although it lost over 100 men. The Japanese planes managed to locate and hit Lexington and Yorktown as well. Yorktown suffered only a minor damage, while Lexington was damaged beyond repair. Fletcher ordered withdrawal.
Despite the fact that Fletcher withdrew, the Japanese commander of the Operation Mo (codename for invasion of New Guinea), Shigeyoshi Inoue called off the invasion. He feared that there may be more American carriers in the area, while the heavy aircraft loses prevented him from proving the planned invasion operation a satisfactory aerial support. Tactically, the Japanese won the Battle of Coral Sea because the loss of the Shoho was less "painful" than the loss of the Lexington. However, the Battle of Coral Sea was a strategic victory for the Allies as their main goal was achieved – preventing the Japanese from capturing Port Moresby. The battle also lifted the Allied morale because after series of defeats against the Japanese, they forced them to abandon their operation for the first time since the opening of the Pacific theater.
Yamamoto ordered Inoue to turn around his ships and carry out the Operation Mo. The Japanese Admiral, however, refused to cancel the recall of the invasion of New Guinea and ordered Takagi and the commander of the Main Body Support, Aritomo Goto to pursue the Allied ships in the Coral Sea. Takagi and Goto obeyed and returned to the Coral Sea to find Fletcher's forces but they were already too far on the way out of the area. For failing to carry out the Operation Mo, Inoue was relieved from his position in October 1942.
Aftermath
The Battle of Coral Sea had a major influence on the Battle of Midway and Yamamoto's failure to establish Japanese naval supremacy in the Pacific. He erroneously thought that two carriers were sunk in Coral Sea. The carrier Yorktown was damaged in the battle but the ship was back in the Pacific fully operational before the Battle of Midway. The Japanese commander of the Combined Fleet also missed the carriers Enterprise and Hornet which could join the defense of Midway. Combined with the land-based aircraft at Midway, Yamamoto no longer enjoyed numerical superiority over the Americans as he thought he would.
The results of the Battle of Coral Sea, however, were not clear immediately because both sides underestimated their loses and exaggerated with the loses of the other side. Thus the Australian and US troops in Australia were initially disappointed with the outcome of the battle because they were convinced that the Japanese did not give up the plan to invade New Guinea but only postponed it. They were right and the Japanese indeed made another attempt to capture Port Moresbay in July 1942, however, due to the loses they suffered during the Battle of Midway they were unable to invade from the sea. Instead, they launched a land offensive along the Kokoda Track but the Allies who meanwhile reinforced their positions in New Guinea repulsed the Japanese attack.
