In the summer of 1944, the U.S. military won successive victories in the southwest and central part of the Pacific theater, which also forced the war away from the Japanese mainland step by step, and the U.S. bombers at that time could already bomb Japan directly. At this time, the Joint Chiefs of Staff of the US military proposed two different plans to attack Japan: First, General MacArthur proposed to reoccupy the Philippines first and then Okinawa and use it as a springboard for attacking the Japanese mainland; Admiral Nimitz believed that Okinawa and Taiwan should be bypassed the Philippines and directly captured and used as a meeting point, and at the same time could serve as a springboard for later entry into Chinese mainland and attacks on Japan's southern islands. In the end, the two sides quarreled with Marshall, who stated his views to Marshall, pointing out that it was not advisable to bypass the Philippines and attack Taiwan directly, because Taiwan, unlike the Philippines, had been under Japanese rule for nearly half a century, and the local people might not support the US military as much as the Filipinos, and the United States had a moral obligation to liberate the 17 million pro-Western Filipino people and the tens of thousands of US prisoners held on the Bataan Peninsula. He stressed: If we bypass the Philippines, we will be tantamount to acknowledging the rumors spread by the revolutionary army that the United States has abandoned the Philippines and is unwilling to sacrifice the lives of American soldiers to save the Philippine people, which will be extremely detrimental to the prestige and influence of the United States in the Far East.

Marshall believed that an important reason MacArthur was so strongly in calling for an attack on the Philippines was to fulfill the vow he had made when he evacuated the Philippines in 1942 to retake the Philippines, and he reminded him not to let personal feelings override the strategic goal of ending the war at an early date, and said that bypassing the Philippines was not abandoning the Philippines.

Although the routes are different, the name of Peleliu Island appears in both schemes. The 1st Marine Division of the U.S. Army has been designated as an offensive force. In order to settle the differences, US President Franklin D. Roosevelt personally flew to Pearl Harbor to meet with the two commanders to discuss the plan of the march. The real purpose of Roosevelt's trip was to win the election by winning points for MacArthur, who is considered a hero by many Americans, on the eve of the approaching election. After consultations with Admiral MacArthur and Admiral Nimitz, it was finally decided to occupy the whole of the Philippines before attacking Taiwan. Roosevelt made a brief speech upon his return to the United States, declaring that he was in complete agreement with General MacArthur. The signal could not be clearer that the Philippine campaign is not far off. But just before MacArthur was preparing to reoccupy the Philippines, in order to ensure the security of the right flank, the U.S. military decided to make the Palau Islands, especially Peleliu and Angor, strategic points that must be conquered. This idea was questioned by many before the Battle of Peleliu was launched, and some later even considered the capture of Peleliu to be completely unnecessary.

When the news of the German army's defeat in the Battle of Kursk came, the Japanese base camp was full of anxiety, and the Japanese naval and army generals in the staff headquarters were even more confused with each other's accusations, and after the sea and land blamed each other, they finally sat down again and began to study the next step of the operational arrangements, and unanimously agreed that the task of stabilizing the Pacific front under the circumstances of 1944 was the focus of Japan's operations, and that Japan's operations could no longer be counted on by others at all, and they could only rely on their own strength to complete them. Therefore, the army should immediately end the special exercise in Guam, allocate troops to strengthen the combat forces in the home and Pacific regions, and prevent the US army's all-out counterattack in the Nanyang region and an attack on the mainland; the Japanese army decided to withdraw enough ammunition from the Manchurian Kwantung Army for 22 battles to strengthen the local defense, and to draw some elite troops back to strengthen the local army's ability to form new troops; With regard to the Pacific Theater, the Japanese Army decided to increase the number of troops to the Pacific Theater by 1 million troops from the end of 1943 to the end of 1944, and to provide sufficient ammunition, weapons, and other combat materials for the Pacific Theater.

Because the strength of the Japanese Army was not enough to draw out so many elite troops to go to the Pacific Theater, and the Japanese Navy did not have enough escort force to escort so many transport ships loaded with troops and ammunition to the south, the Japanese Army had no choice but to send troops to the Pacific Theater by means of transportation in batches and key areas, and the Japanese Army divided the Pacific Theater Theater Theater into three defense circles, and the outer ring defense circle was the key defense circle, especially the key points in Truk Island, Rabaul, and the eastern part of the Dutch East Indies. The troops sent to the area are fully equipped with elite units carrying heavy weapons, and as for the Central Defensive Circle, light troops are sent to strengthen them, and the heavy weapons and strength of the troops are reduced. As for the inner ring area, it is mainly reinforced by a frame of troops composed of only symbolic heavy weapons, consisting of new recruits and a few veteran cadres. In this way, most of the Japanese troops in the Pacific were dispatched, and because they did not require heavy equipment and a large amount of war materials, the need for ships was greatly saved, and the pressure on the navy's escort and shipping capacity was reduced. For example, for the elite troops transported by the Japanese army to the outer ring, one division and regiment together with equipment and materials need at least 45 transport ships to transport, while one lightly armed division and regiment transported to the central ring only needs 12-16 transport ships, and as for one shelf division and regiment to the inner ring, only 6 transport ships are needed to transport the equipment.

The Japanese army's wishful thinking was to inflict heavy damage on the US military with elite troops in the outer ring, and to plunge the US troops into a long-term war in Indonesia and Rabaul, so that the navy and the army in the rear would have a chance to fully recuperate. The Japanese army was convinced that before 1944, the U.S. military would not be able to completely capture the key areas in the outer ring, so that the Japanese army would have sufficient time to strengthen the central ring, and after a period of time, it would be possible for the central ring to send strong troops to reinforce the outer ring to fight, or the outer ring troops could shrink to the central ring to build a stronger defensive line of the army, and the troops in the inner ring had become veterans after these years, and the untrained recruits had also become veterans, and the frame troops had also become a full force, which could be used as a reserve decisive battle force to deal a fatal blow to the U.S. troops who had gone through the outer ring with major attrition. Naturally, on the mainland, the Japanese army will be able to arm groups of new elite divisions after a certain period of time by using the elite troops remaining on the mainland and a large number of heavy weapons as the backbone, and the navy's fleet will be able to win a decisive battle again after a full rest, so that Japan will be in a position where it will be difficult to be defeated, and the United States will waver in its determination to continue the war, so that Japan can get a favorable outcome of the war.

At the beginning of 1944, the deployment of the Japanese army to Indonesia and Rabaul to send strong troops has been completed, and began to send troops to the inner ring of Central, at this time, the Japanese army felt that the reserve of elite troops was insufficient, and thought that the US army would first attack the eastern part of Indonesia, relying on Australia as a base, and gradually occupy the oil fields controlled there by advancing from the east, while there were enough strong troops in eastern Indonesia, and the outer ring defense was already solid, so it was not urgent to strengthen the central ring, and most of the troops sent to the central ring had become shelf troops. Rather than the more elite lightly armed troops originally planned, the troops sent to Malaysia and the western islands of Indonesia were basically composed of untrained recruits, no different from those sent to the Philippines, and there was no heavy equipment.

However, there are two important islands between the Central and Inner Rings, one is the Palau Islands and the other is the Mariana Islands, and it is necessary to send relatively strong troops to defend, but the Japanese army is going to launch a mainland opening operation, so it cannot draw two elite troops for a while, and only the 14th Division can be drawn out of the elite troops, so where the 14th Division is stationed has become a problem. Because the Japanese army is building a large airfield in the Palau Islands, in addition to the combined fleet has shrunk to the Philippines, the base in Saipan has been empty, so it was finally decided to transfer the 14th Division to the Palau Islands, the Palau Islands were obtained by the Japanese army after World War I, there is a good deep-water port, can dock a large fleet, in addition to the islands The Japanese army is also building a Pacific largest airfield, the geographical location is very important is an important hub connecting Saipan and the Philippines, Therefore, it is not surprising that the Japanese army decided to send the 14th Division to Palau.

The 14th Division of the Japanese Army is a permanent division, received an order to move to Palau in Manchuria, and made light preparations, transferred a large amount of heavy equipment back to the mainland, and reorganized according to the establishment of the Marine Mobile Division, unlike the 29th Division, which was also converted into a marine division, and the so-called permanent divisions sent to the Philippines, the sequence of the 14th Division's attack on the Pacific Ocean was not composed of a small number of backbone soldiers plus a large number of newly mobilized soldiers, all of them were still composed of the original soldiers and officers, and the infantry units remained unchanged. It is a veritable elite unit, not an empty shelf division that has been drawn out of the real main force and can only scare people, of course, after being transferred to a marine division, the firepower of the 14th division has been withdrawn back to the mainland a lot, which has a certain impact on combat effectiveness.

In April 1944, more than 13,000 officers and soldiers of the 14th Division turned into a marine division took 16 transport ships and arrived safely in the Palau Islands under the strict protection of destroyers, 2 air teams, 1 base guard special marine team, and an engineering team of more than 10,000 Korean migrant workers were used to construct the fortifications.

After the 14th Division took over the defense of the Palau Islands, the main force of the division and the 1st Marine Mobile Brigade were deployed on the main island, the 2nd Infantry Wing of the 14th Division and the 45th Base Garrison Special Marine Corps of the Navy were deployed on Berry Iwo Island, which was more than 50 kilometers away from the main island, and 1 infantry brigade was deployed on Unger Island, and the Japanese army only deployed 3 islands, and the other islands were too small to be of any value. The real focus of the Japanese defense of the Palau Islands was the main island of Barber Tuap Island and the island of Berry Iwo, because these two islands had airfields, and as for Unger Island, there were also conditions for building airfields, so the Japanese army also deployed one brigade.

After the elite 14th Division deployed to defend Palau, it began to actively carry out training for war, carried out comprehensive surveying and offensive and defensive exercises on various islands day and night, familiarized itself with the terrain and environment, and used the engineering team composed of Korean migrant workers to build a large number of fortifications, and stationed more than 700 Korean migrant workers to build fortifications on Ungel Island, more than 3,000 Korean migrant workers to build fortifications on Peleliu Island, and more than 8,000 Korean migrant workers to build fortifications on Baber Tuap Island. Although the Japanese army was actively preparing for war in Palau, it did not really have the idea of fighting the US military in the Palau Islands, and it was generally believed that the war was very far away, and it was just training and familiarizing themselves with the operating environment in the Pacific theater. The officers and men of the 14th Division of the Japanese Army believed that it was likely that they would reinforce the Japanese troops in the outer ring and engage in fierce battles against the American troops in the outer ring.

However, in June 1944, the U.S. Army jumped over the outer ring of the Japanese army and went straight to Saipan, due to the lack of preparation of the Japanese army in Saipan, the lack of ammunition and troops, and the blind underestimation of the enemy in the early stage of the battle, and finally failed, and then the Japanese army on Guam was also defeated, although the U.S. landing force also suffered serious losses, but because of the defeat of the Mariana Islands in a short period of time, it obtained an important base for directly attacking the Japanese mainland and destroying the Japanese inner defense circle, and severely damaged the Japanese Navy Combined Fleet, which was in a hurry to attack due to the danger of Saipan, and its morale was greatly boosted. However, the Japanese army's plan to resist from the outside to the inside layer by layer and consume the US army completely failed, and the situation in the Pacific War deteriorated sharply, and the Palau Islands were already under the US army