July 1, 1944: Setting the Sun
Admiral Nimitz sighed as he leaned back in his desk at the 5th Fleet's Naval Headquarters at Guam. It was done. It had taken every flight deck the USN had at sea to destroy the last great assault by the Japanese Navy, but it was done.
The IJN had sortied in strength, pitting four CVs against Allied supply lines near Pearl Harbor. It was an audacious move and had nearly succeeded. It was blind luck that the Enterprise and Essex had left Pearl Harbor to escort the troop convoy to the South Pacific. Many had said it was unnecessary, that the IJN had retreated to Tokyo Bay, but Nimitz had overruled them. But still, it had been costly. Enterprise was severely damaged and the Essex would also require a moderate stay in the sprawling shipyard at Pearl. But they had repulsed the IJN, damaging two of the CVs, and setting the stage for one of the greatest chases in naval history.
Six fleet carriers had been detached from the Phillipines Convoy Staging Area and set to intercept the marauders before they could reach safe harbor. And intercept they had. The enemy had broken off into two TFs, apparently in an attempt to ensure that at least 2 CVs would return to Tokyo. TF 78.1, led by the battle veteran Yorktown, caught the Hiryu and Echiago near the Marshalls and devastated them with no losses of their own. TF 78.2 caught the Akagi and Kaga near Wake Island and sunk both of the CVs, again with no loss of their own.
Nimitz sighed again and turned his eyes to battle reports. Four IJN CVs destroyed at a cost of two damaged on the Allied side. Yes, he would take that victory any day. The IJN had just taken a fearful loss. Operation Grand Slam
After careful consideration, it was determined that the most effective method of cutting Japan off from their industrial lifeline in the DEI would be the neutralization of the Philippines. Invading the Japanese home islands would require the invasion of Iwo Jima as well as the surrounding islands, which offered little in the way of airbases and naval facilities. Attempting a reduction of the Japanese home islands from these bases was discarded as ineffective.
Thus, the invasion of the Philippines was initiated in the first 6 months of 1944.
The initial landings were made at the southern point of Luzon at Naga. The campaign progressed rapidly with Manila and Clark Field secured by June. Japanese losses were incredibly heavy in both men and materiel, with over 700 aircraft lost as well as at least 4 divisions of IJA troops.
In addition, with the Philippine Sea secured IJN losses in cargo and tanker vessels skyrocketed. IJN convoys are now taking the long route through the Sulu Sea, costing them time and fuel. With Luzon secured, the noose will tighten and supply transport out of Honshu should slow to nothing.