In June 1944, the United States changed its strategy of "island-by-island attack" in the Pacific battlefield to the "leapfrog strategy", that is, it crossed some secondary islands defended by the Japanese army to seize the most critical and important islands in the Pacific. stronghold, cut off Japan's sea and air communication lines and establish a strategic naval and air force base for the United States. Therefore, the US military decided to bypass the Caroline Islands and go straight to the Mariana Islands. Its purpose was to conquer Saipan and Tinian Island, recapture Guam, and break through Japan's internal defense circle.
Admiral Nimitz, commander-in-chief of the U.S. Pacific Fleet, named the battle "Operation Surprise" and personally commanded it. To this end, more than 640 warships, including the U.S. 5th Fleet and the 58th Aircraft Carrier Task Force, were dispatched, more than 1,000 carrier-based aircraft, and 620 land-based aircraft. The landing force was 3 Marine Divisions, 2 Infantry Divisions, and 1 Marine Brigade*** 128,000 people. On June 11, 1944, the U.S. Task Force 58, commanded by General Mitchell, took off 225 carrier-based aircraft to conduct a raid on the airport on Saipan.
By August 3, 1944, most of the nearly 10,000 Japanese troops on Tinian Island were wiped out, and Lieutenant General Kakuharu Tsunoda, commander of the First Air Force, died in battle. On August 11, 1944, Lieutenant General Hideyoshi Obata, commander of the 31st Army, the supreme commander of the Japanese garrison on Guam, committed suicide. Most of the more than 18,000 Japanese troops on the island died in battle. "Operation Surprise" achieved a complete victory, and the U.S. military occupied the Mariana Islands and broke through Japan's inner defense circle. In response to this, the Japanese ruling group panicked and internal conflicts intensified. Tojo Hideki was forced to resign as prime minister and replaced him with Army General Kuniaki Oiso, the former governor of Korea, known as the "Tiger of Goryeo". Guam is the largest island in the Mariana Islands, 30 miles (48 kilometers) long and 9 miles (14 kilometers) wide. It was occupied by the United States from Spain in 1898 until the attack on Pearl Harbor on December 11, 1941. It was ruled by the United States until it was occupied by the Japanese. This was not the case with other highly fortified islands in the Mariana Islands such as Saipan, because Saipan was ruled by Japan after World War I. In 1944, a large number of garrison troops were stationed.
The Allies' plan to invade the Mariana Islands called for intense bombing, first from aircraft carriers and shore-based aircraft from the Marshall Islands to the east, and then, when air superiority was gained, inshore bombardment from battleships, Guam It was selected as the target because its large area can be used as a logistics base for the Allied forces to support the next military operations against the Philippine Islands, Taiwan and the Ryukyu Islands; the Apra deep-water port is suitable for large ships to berth; the two airports on the island can also be used For B-29 Superfortress bombers to lift and land.
The military invasion of Saipan was scheduled for June 15, 1944, and the landing operation on Guam was tentatively scheduled for June 18. The original timetable was very modest, but after The appearance of an unexpectedly large number of defenders on Saipan put up very tenacious resistance and a large-scale attack by Japanese aircraft carriers delayed the invasion of Guam for a month. Guam is surrounded by reefs, cliffs and large rocks, so it is a big challenge for offensive forces. On July 21, the US military landed on both sides of the Cape Oroland Peninsula in western Guam in an attempt to cut off the airport. The US Marine Corps The 3rd Division landed near Agana in the north of the peninsula at 8:28 a.m., and the 1st Marine Reserve Regiment landed in the south near Agat. Japanese artillery fire destroyed 20 tracked amphibious landing vehicles. But by 9 o'clock, all the tanks had landed on both beaches. The landing operation of the US 77th Infantry Division was even more difficult. Due to the lack of amphibious vehicles, the soldiers needed to wade through the water full of reefs after leaving the landing craft.
The U.S. military set up a bridgehead about 2,000 meters deep at night. The Japanese army continued to launch counterattacks in the first few days of the battle, mostly at night and using infiltration tactics. They infiltrated the U.S. defense lines several times, but Forced to retreat after losing a large number of personnel and equipment, senior Army Lieutenant General Kaneshiro was killed on July 28, 1944, and Lieutenant General Obata Hideyoshi took over the command.
The U.S. military's supplies encountered difficulties on the first day of the battle. The landing ships failed to approach the reef hundreds of feet away from the beach, and there was a lack of amphibious vehicles. However, the two beachheads were connected on July 28. , while Cape Oro Airport and Abra Port were captured by the US military on July 30, 1944.
The counterattack on the U.S. beachhead left the Japanese army exhausted. In early August 1944, they were short of food and ammunition, and had only a handful of tanks left. Obata therefore withdrew his troops to the south of Guam. , planned to use the mountainous area in the center of the island to carry out stubborn resistance, but the US military controlled the sea and air near Guam, so the Japanese army could not expect to receive supplies and reinforcements. Obata Hideyoshi only hoped to delay the complete defeat for a few days.
Heavy rain and dense jungle made the U.S. military face a difficult situation. However, after the breakthrough at Barrigada Mountain from August 2 to August 4, 1944, the Japanese defense line collapsed; The next battle was a pursuit to the north. As in other situations in the Pacific battlefield, the Japanese army refused to surrender and almost all soldiers were killed. The Japanese army has built three airports in Guam, of which the third airport has not yet been completed. At first, the Japanese army did not pay much attention to the defense of Guam. It was not until the fall of the Marshall Islands that the Japanese army began to strengthen the defense of Guam. The Japanese army's reinforcements to Guam were much more successful than those of Saipan, and a large number of reinforcements and supplies were shipped to Guam.
The defenders of Guam are the 29th Infantry Division of the Army, the 48th Independent Mixed Brigade, the 10th Independent Mixed Regiment, the 52nd Anti-aircraft Artillery Group and the 54th Navy The garrison has more than 20,000 troops, more than 20 artillery pieces, and more than 40 tanks, under the unified command of Lieutenant General Gao Pinbiao, commander of the 29th Division. The 29th Division was originally the Kwantung Army. It was well-trained, well-equipped, and had strong combat effectiveness.
Although Guam was a U.S. territory for more than 40 years before the war, the U.S. military only discovered that the relevant information was very sketchy when it began to plan an attack on Guam, and it knew nothing about the situation after the Japanese occupation. We know this, so we continue to use aircraft to conduct aerial photography reconnaissance.
The U.S. military originally planned to land on Guam on June 18, 1944. However, after the Saipan landing operation, it felt that the strength of the landing force needed to be strengthened, and it would take some time for the reinforcements to arrive on the battlefield. The Shanghai Navy Fleet also had to use all its strength to deal with the Japanese mobile fleet, so Spruance decided on July 8, 1944 to postpone the landing operation to July 21, 1944. The landing force included the original 3rd Marine Division and the temporary In addition to the First Brigade, the 77th Army Division was also added. The Seventy-seventh Division was originally the general reserve force and was on standby at Pearl Harbor. After receiving the order to join the war, it left Pearl Harbor in early July 1944 and arrived at Eniwetok Lagoon in the middle of July. The landing on Guam is still undertaken by the Southern Group commanded by Major General Connolly. This group consists of 6 battleships, 5 escort carriers, 10 cruisers, 53 destroyers, 2 frigates, 75 landing ships, and 21 transport ships. , plus minesweeping, logistics and other ships, the total number is 265. The ground combat troops include the Third Marine Division, the First Temporary Marine Brigade, and the 77th Infantry Division, totaling approximately 55,000 people.
The U.S. military’s artillery preparations for Guam began as early as June 11, 1944. All Japanese aircraft on the island were wiped out, and the Japanese airport was also severely damaged and unable to be used. From June 21, 1944 to July 7, 1944, the U.S. military conducted several naval and aircraft bombardments on Guam. In view of the fact that only two days of artillery preparations were carried out before the landing on Saipan, the effect was very unsatisfactory and the landing was The troops suffered huge casualties, so the US military vigorously strengthened its artillery preparations for Guam. Starting from July 8, 1944, it conducted a fierce artillery bombardment that lasted for thirteen days, firing 6,258 406 mm artillery shells and 356 mm artillery shells, and 3,862 203 mm artillery shells. 2,430 rounds of 152mm artillery shells and 16,214 rounds of 127mm artillery shells. Although the Japanese army took advantage of the delayed landing of the US military to set up a large number of obstacles and mines on the beaches where the US military might land, and rushed to repair some permanent firepower points and defenses on the island. This long-term bombardment by the US military severely damaged the Japanese defenses and destroyed almost all the exposed firepower points of the Japanese army. The effect was relatively significant.
Starting from July 16, 1944, the U.S. Navy’s 3rd, 4th and 6th Underwater Demolition Teams carried out underwater blasting on the beach where they were about to land for three consecutive nights, blowing up reefs and obstacles. , clearing the way for landing.
On July 19, 1944, and July 20, 1944, all US warships serving as naval gunfire support carried out extremely violent bombardments at the landing sites of Agat and Asan.
On July 20, 1944, Spruance personally arrived in Guam on the flagship heavy cruiser USS Indianapolis to supervise the war. On July 21, 1944, the sky was clear and the wind was calm. It was a good weather for fighting. Starting in the early morning, the US military provided direct fire support with 6 battleships, 3 escort aircraft carriers, 8 cruisers and 32 destroyers, and also used A new tactic in which warships and aircraft carry out coordinated attacks on the same target at the same time. It is stipulated that the ballistic trajectory of naval guns shall not be higher than 365 meters, and the bombing height of aircraft shall not be lower than 457 meters, so that the naval guns and aircraft can exert greater power.
At 8:30, with the support of fierce artillery fire, the U.S. military began to assault the land. The Third Marine Division landed on Asan Beach in the northern part of the Orot Peninsula. The First Marine Brigade and the Seventy-seventh Division landed on the Orot Peninsula. Landing at Agat Beach in the southern part of the Rote Peninsula. At Asan Beach, three regiments of the Third Marine Division launched at the same time and assaulted side by side on the 1,800-meter-wide beach. Because there were many coral reefs on the coast, only crawler landing vehicles could land, so they relied on crawler landing vehicles to transport the troops back and forth. The initial landing was very difficult. It went smoothly, and the Japanese resistance was negligible. Around noon, all the division's troops, vehicles, and artillery landed ashore. It was immediately discovered that the terrain of the landing beach was extremely unfavorable. There was high ground in the front, the sea in the back, and steep cliffs on both sides. The Japanese army was on the top of the mountain and on the reverse slope on three sides. The artillery deployed condescendingly covered the entire landing beach. More than 20,000 US troops were crowded on the small landing beach. Every artillery shell fired by the Japanese army would cause huge casualties to the US military. The terrain to be attacked by the Third Marine Regiment was the most dangerous, so the casualties were the largest and the progress was the smallest; The 21st Marine Regiment and the 9th Marine Regiment were in a relatively better situation. With the effective support of naval gunfire, they both occupied the hilltop in front of them and repelled the Japanese counterattack.
The Japanese resistance at Agat Beach in the south was more fierce than in the north. As soon as the U.S. tracked landing vehicles arrived at the coral reef, they were violently bombarded by Japanese artillery fire. In an instant, 24 tracked landing vehicles were destroyed, accounting for the total number of them. Due to the heavy losses of the tracked landing vehicles, many soldiers had to wade ashore and were suppressed in front of the Japanese firepower, unable to move forward. The supplies were not transported ashore as planned, and the landing encountered great difficulties. The 1st Marine Brigade fought hard and reached the first target at about 11 noon. The commander of the 1st Marine Brigade also came ashore, opened a command post, and led the troops to fight bravely. The tanks that accompanied the landing troops ashore were never able to enter the battle due to the complex terrain, obstacles, mines, and wrong guidance. Only one tank played a role in the fierce battle for the Ga'an stronghold. It went around to the rear of the Japanese position and used The artillery fire destroyed the strongholds and opened the way for the infantry to advance. Throughout the day, the fighting was fierce. After nightfall, the Japanese army launched a counterattack as usual. The US military was well prepared and continuously fired flares. As soon as it discovered the Japanese attack, it immediately summoned naval gunfire to fire. Although the Japanese offensive was fierce, it was no match for the US artillery fire.
On July 22, 1944, the U.S. military at Asan Beach in the north began to advance with the support of naval gunfire. The Ninth Marine Regiment captured the Piti Shipyard, and its leading troops had arrived at the Apra Port. ; The 21st Marine Regiment captured the high ground in front of them and drove the Japanese troops down the hill; the 3rd Marine Regiment was the most difficult, suffering heavy casualties and making slow progress. After many reinforcements, they captured the high ground overlooking the landing beach and advanced to Agra. to the Tengjue Highway, allowing US tanks to advance along this road. It was also a hard battle on the southern beach. After a bloody battle, the 4th Marine Regiment cleared the Japanese troops on Alifan Mountain. Although the 305th Regiment of the 77th Infantry Division made slow progress, it finally joined the 1st Marine Brigade at nightfall. , forming a unified and consolidated landing site.
On July 23, 1944, the southern U.S. military continued to develop its offensive and finally captured all the high ground overlooking the beachhead.
On July 24, 1944, after three days of fierce fighting, the U.S. military in the north cleared all the Japanese troops on the high ground overlooking the beach. The U.S. military in the south began to attack the enemies of Sumai. The Japanese army resisted desperately and stopped the U.S. offensive.
On the evening of July 25, 1944, the Japanese army launched a fierce counterattack against the U.S. military. This was carefully prepared for many days. It targeted the gap in the U.S. military's defense line. First, it concentrated artillery bombardment, and then A small group of troops penetrated and assaulted. The U.S. military responded with all its strength and repelled many Japanese charges. However, the Japanese army ignored the casualties and attacked wave after wave. Finally, it broke through the U.S. defense line from the gap between the 3rd and 9th U.S. Marine Regiments in the north. Some Japanese troops even rushed to the beach. The U.S. military rear quickly organized service personnel to intercept them. One group of Japanese troops even rushed to the field hospital of the U.S. Third Marine Division. The sick and wounded took up arms and went into battle. The wounded who could not move even lay on the bed. After firing, the US military quickly mobilized two engineering companies to eliminate this Japanese army. Fighting in other areas continued until noon on July 26, 1944, finally crushing the Japanese counterattack, leaving as many as 4,000 corpses behind.
On July 26, 1944, Major General Shigematsu, commander of the 48th Independent Mixed Brigade of the Japanese Army, died in battle.
On July 27, 1944, the 77th Division of the Southern US Army captured Mount Tengjue, the commanding heights of Guam. The 22nd Marine Regiment attacked a high ground overlooking the airport under fierce artillery fire. Unable to hold up under artillery fire, they gave up the high ground before the US military could launch an attack. On the same day, U.S. forces in the north occupied Fanti Mesa.
On July 28, 1944, the US military finally captured Sumai, and the troops from the north and the south met at Tengjue Mountain. That day, Lieutenant General Gao Pinbiao, the top commander of the Japanese Army in Guam and commander of the 29th Division, was killed in the battle. Obata, commander of the 31st Army who came to Guam to inspect and was stranded due to the start of the battle, took over the command. Obata was well aware that the U.S. military had a great advantage in terms of strength and firepower. In order to carry out protracted resistance, he left only two brigades to cover the narrowest waist of Guam, and personally led the main force to withdraw to Santa Rosa Mountain in preparation for the final battle.
On July 29, 1944, the 1st Marine Brigade captured the Orot Peninsula, so that the US military controlled half of Guam. Major General Geiger, commander of the Third Marine Corps, the highest commander of the US military in Guam operations, decided to adjust the deployment. The 3rd Marine Division was on the left and the 77th Infantry Division was on the right to attack north side by side. The 1st Marine Brigade was responsible for covering the rear and clearing out the already The remnants of the Japanese army in the occupied areas. After a brief rest on the battlefield, the U.S. military launched an attack on July 31, 1944. With the strong support of naval gunfire, the attack went smoothly. At about 11 o'clock, the third Marine Regiment occupied Agra, the capital of Guam.
On August 1, 1944, Geiger ordered the U.S. military to speed up its advance and strive to capture Santa Rosa Mountain before the Japanese army established a final line of defense.
On August 2, 1944, the US military captured Tiyan Airport.
On August 3, 1944, the Seventy-seventh Division captured the village of Barrigada. The well in the village solved the problem of lack of fresh water for the US military.
On August 4, 1944, the U.S. military captured a solid defensive position of the Japanese army and wiped out 346 enemies.
On August 6, 1944, the U.S. military advanced to the foot of Santa Rosa Mountain and was blocked by Japanese artillery fire. The U.S. military immediately called in naval gun support and quickly suppressed the Japanese artillery fire.
On August 7, 1944, the 1st Marine Brigade completed the task of clearing the rear and joined the attack on the left wing of the 3rd Marine Division.
On August 8, 1944, the Seventy-seventh Division captured Santa Rosa Mountain, and the 1st Marine Brigade advanced to Cape Litidian.
On August 9, 1944, the leading troops of the Seventy-seventh Division arrived at Patty Point.
On August 10, 1944, Obata sent his final farewell message to the Tokyo base camp. The U.S. military reached the northernmost tip of Guam, and Geiger announced that the organized Japanese resistance on Guam had been eliminated.
But the battle was not over. On August 12, 1944, the US military captured the last Japanese position. Obata and the command staff were either killed or committed suicide. At this point, the Japanese resistance was basically be pacified.
There were still about 9,000 Japanese troops hiding in the jungles and caves on the island. They came out from time to time to harass and mop up the remaining Japanese troops until the end of the war. In September 1945, the last batch of about 100 Japanese troops came out to surrender. Most of the 9,000 Japanese troops came out to surrender. The troops were cut off from supplies and died of cold and starvation in the jungles and caves. In the Battle of Guam, 1,435 U.S. troops were killed and 5,648 wounded. The Japanese army killed 18,560 people and captured 1,250 people. The U.S. military's casualties were almost half less than those on Saipan, mainly because the U.S. military delayed the landing by more than a month and made full use of this time to increase offensive forces and strengthen naval gun and aviation firepower preparations. This is because the US military has fully learned from the experience and lessons of Saipan, and at the same time proved the importance of artillery preparation in landing operations. From this, it seems that it is extremely wise for the US military to postpone the landing. A few Japanese soldiers still resisted in the jungle. On December 8, 1945, three U.S. Marines were ambushed and killed. On January 24, 1972, Army Sergeant Shoichi Yokoi was discovered by a hunter. He was already in the jungle. He lived alone in the cave for 27 years.
After the battle, Guam became a base for Allied operations. The U.S. Naval Engineer Battalion built five large airports on the island. B-29 Superfortress bombers took off from the island to bomb the Western Pacific and Japanese homeland targets.
Three members of the U.S. Marine Corps were awarded the Medal of Honor for their heroic performance in the Battle of Guam: Private First Class Frank Wei Ruowang (posthumously), Private First Class Leonard Mason (posthumously) and Captain Louis Wilson (later General).
Guam regards July 21, 1944 as Liberation Day.