Before the attack on Pearl Harbor, the ratio of naval forces in the Pacific was only slightly in favor of Japan:1 1 Japanese battleships against 1 0 allies, 1 1 aircraft carriers against 4, 34 cruisers against 35, 110 destroyers against 90. In the spring of 1944, this gap had widened considerably:the Imperial Navy fielded 11 battleships against 0, 10 aircraft carriers against 3, 25 cruisers against 8, 70 destroyers against 14. Masters of the seas, the Japanese the are also air (thanks to their on-board aviation and the excellent quality of their fighters) as well as land, since in addition to the continental countries and the large islands of Southeast Asia their "defensive perimeter" includes the Guam islets and Wake, the Marshall and Mariana Islands and the Bismarck Archipelago.
Reduced to the defensive, the Americans divided the remnants of their Pacific Fleet into 2 Task Forces (raiding forces). Command of the combined operations to recapture Southeast Asia was given to General MacArthur, with Admiral Chester Nimitz in charge of fleet and naval operations throughout the Pacific. In mid-April, a formation of B-25s from the aircraft carriers Hornet and Enterprise bombed Tokyo and 2 Japanese cities in broad daylight, then landed somehow in China. The destruction is insignificant, the operation is more of a "bluff" than a real attempt to go on the offensive, but it takes on symbolic value for both sides. On the American side, it boosts the morale of the fighters and the rear, hard hit after the defeats of Pearl Harbor and Bataan. On the Japanese side, it struck public opinion with amazement, persuaded by official propaganda that all of Japan's enemies had been crushed by its valiant armies, and dispelled the illusions of the Imperial General Staff, which finally understood, after its t be left intoxicated by your victories, that the real war has only just begun. Admiral Yamamoto, who inspired the raid on Pearl Harbor, understands better than anyone that the attack was a political and military failure. To fall back on the conquered territories, leaving the US Navy time to recover from the blow received would be a serious mistake. To defeat the United States before its formidable economic power has allowed it to turn the situation around, it is necessary to force its fleet to fight, oppose the main body of the Imperial Navy and crush it in a single battle.
Thus was born the idea of an attack against Midway:Lost in the center of the Pacific, the small island of Midway (whose name means halfway) would allow the Japanese, if they could master it, to directly threaten the Hawaiian Islands and the west coast of the United States. Logically - and this is what Yamamoto hopes - the Americans will therefore throw all their forces into the defense of Midway. A diversionary operation threatening the Aleutians, in the North Pacific, will then make it possible to divide them, by removing one or two aircraft carriers, and to complete in one day the work of destruction begun at Pearl Harbor. Yamamoto's plan is excellent, the opportunity could not be more favorable at the end of April, but the Imperial General Staff let it pass by deciding to launch Operation Mo beforehand, intended to settle the New Guinea problem. Japanese troops have in fact taken a foothold on the northern coast of New Britain, in New Ireland part of the Solomons.
The capture of Tugali (Solomon) and especially of Port Moresby on the south coast of New Guinea, would open the road to Australia for them and would force the Americans to abandon the entire southwest Pacific. At the end of April, Admiral Inoye's strike force headed for the Coral Sea. It includes 3 aircraft carriers carrying 180 aircraft, and 6 cruisers. The American fleet defending the Coral Sea consists of 2 aircraft carriers, carrying 121 aircraft, and 7 cruisers. The battle that is preparing will therefore oppose adversaries of roughly equal power, the slight inferiority of the American fleet being compensated for by the fact that the specialized services of the Navy are able to decipher all the messages of the Imperial Navy. On May 3, the Japanese took Tulagi, then bypassed the Solomon Islands to the west. On the 6th, when Corregidor had just capitulated, the 2 enemy squadrons were in the Coral Sea, each trying in vain to spot the other. On the 7th, the Japanese fighter bombarded an American tanker and its escort - which it took for an aircraft carrier and a cruiser, while the American fighter, believing it was dealing with the invasion force of Port Moresby, ran into the covering force of the Japanese squadron and sinks the light aircraft carrier Shoho.
The Battle of the Coral Sea begins on the morning of the 8th. Opposing fighters seek each other in the clouds, criss-cross the Coral Sea, locate and attack aircraft carriers. Hit by 3 bombs, the Shokaku loses some of its devices and has to give up the fight. The losses in aircraft are balanced (74 for the Americans, 80 for the Japanese), but 2 American aircraft carriers are affected:the Lexington is sunk; the Yorktown, which the Japanese believe to have destroyed, will be repaired 2 days later. On the evening of the 8th, the Japanese fleet withdrew. From a tactical point of view, it has won another victory, since the balance of forces present is more than ever in favor of Japan (this is also how the news will be announced in Tokyo). But from a strategic point of view, the Japanese failure is obvious:Inouye had to give up taking Port Moresby and beat a retreat before an American task force, thus destroying the myth - established three months ago - of the invincibility of the Imperial Navy. . If the Battle of the Coral Sea marks the end of Japanese victories, or at least the beginning of American recovery, it is also important, in the evolution of the war, because it is the first engagement "beyond the horizon":the two squadrons met without approaching each other, the ships involved remaining 30 to 150 km apart from each other.
Even if it is no longer presented under the best auspices - 2 Japanese aircraft carriers had to return to their bases, and the Americans had time to reinforce the defenses of the island - the attack against Midway can still reverse the situation. The Japanese fleet, fully mobilized for the occasion, brings together 200 buildings, carrying 600 planes, to which Admiral Nimitz can only oppose 76 ships and a little over 300 planes. Yamamoto, determined to deal a mortal blow to the American fleet, has divided his forces in such a way as to give them maximum efficiency:several squadrons, including a raiding force comprising 2 light aircraft carriers, are to attack the Aleutians - and in principle oblige the American aircraft carriers to go up to the north to try to intercept them;
the attack on Midway must be carried out jointly by an invasion fleet (5,000 men) coming from Saipan, and the raiding force (aircraft carrier, 4, kagi, Kaga, Hiryu, Soryu) of Admiral Nagumo, charged with neutralizing the American fleet and destroying the defenses of Reading; upon their arrival on the scene, the American relief (Pearl Harbor fleet) must be attacked simultaneously by Nagumo's fleet and by the main squadron - 7 battlecruisers and a light aircraft carrier - commanded by Admiral Yamamoto in nobody. The Japanese plan has several weak points. First, the Imperial General Staff is convinced that the Americans have only 2 aircraft carriers left (which is incorrect, since the Yorktown has been repaired), and that they will leave Pearl Harbor to go north as soon as the attack on the Aleutians has been launched. Therefore, unaware that their messages could be decoded, the Japanese had no alternative plan.
Second, Yamamoto has not learned the lessons of the battle "beyond the horizon" of the Coral Sea, intends to settle the fate of the American fleet by means of a classic engagement, in the purest style of traditional maritime warfare
Prisoner of this design, he disseminated his aircraft carriers leaving only 4 (out of 8) at Nagumo's disposal.
The Japanese fleet sets out on May 25. The assault on the Aleutians goes off without a hitch:Dutch Harbor is bombarded on June 3; on the 7th, without encountering any real resistance, the Japanese troops took Kiska and Attu islands. But the Americans, duly informed of the movements of the Japanese ships, did not fall into the trap.