Battle of Guam (1944)

Not to be confused with the Battle of Guam (1941).

Battle of Guam
Part of the Mariana and Palau Islands campaign of the Pacific Front (World War II)
U.S. Army officers planting the American flag
Date 21 July – 10 August 1944 (1944-07-21 – 1944-08-10) (2 weeks and 6 days) Location Guam, Mariana Islands 13°24′10″N 144°39′47″E Result American victory
Belligerents
United States	Japan
Commanders and leaders
Richard L. Conolly Roy Geiger Allen H. Turnage Andrew D. Bruce Lemuel C. Shepherd Jr.	Takeshi Takashina † Hideyoshi Obata †
Units involved
III Amphibious Corps 3rd Marine Division 77th Infantry Division 1st Provisional Marine Brigade	Thirty-First Army 29th Division 48th Independent Mixed Brigade 10th Independent Mixed Regiment
Strength
Assault: 56,537 Garrison: 9,250 Total: 65,787 274 ships	Army: 11,500 Navy: 5,000 Air: 2,000 Total: 18,500 –22,554, 40 tanks, 700 obstacles
Casualties and losses
Marines: (15 Aug.) 1,568 battle deaths 5,365 wounded Army: (10 Aug.) 177–179 killed 29 missing 662–704 wounded Navy/Ships Personnel: Organic to Marine units (15 Aug.) 51 battle deaths 206 wounded Ships: 13+ battle deaths 27+ wounded Total deaths: ~3,000 killed [1]	14,067 dead (buried 15 Aug.) 86 POWs (12 Aug.) Eventually 18,337 dead, 1,250 captured
600+ civilians killed

Map of the battle

The Battle of Guam (21 July – 10 August 1944) was the American recapture of the Japanese-held island of Guam, a U.S. territory in the Mariana Islands captured by the Japanese from the United States in the First Battle of Guam in 1941 during the Pacific campaign of World War II. The battle was a critical component of Operation Forager. The recapture of Guam and the broader Mariana and Palau Islands campaign resulted in the destruction of much of Japan's naval air power and allowed the United States to establish large airbases from which it could bomb the Japanese home islands with its new strategic bomber, the Boeing B-29 Superfortress.

The invasion of Saipan was scheduled for 15 June 1944, with landings on Guam tentatively set for just three days later, but the Battle of the Philippine Sea and stubborn resistance by the unexpectedly large Japanese garrison on Saipan led to the invasion of Guam being postponed for over a month. On 21 July, American forces landed on both sides of the Orote Peninsula on the western side of Guam, planning to secure Apra Harbor. The 3rd Marine Division landed at Asan near Agana to the north of Orote, and the 1st Provisional Marine Brigade landed near Agat to the south. The men stationed in the two beachheads were pinned down by heavy Japanese fire, making initial progress inland quite slow. Supply was very difficult; landing ships could not come closer than the reef, several hundred yards from the beach, and amphibious vehicles were scarce.

The 1st Provisional Brigade blocked off the Orote Peninsula on 25 July, and that night the Japanesecounterattacked, in coordination with an attack against the 3rd Marine Division to the north. The effort was a failure. On 28 July the two beachheads were linked, and by 29 July the Americans had secured the Orote peninsula. The Japanese counterattacks against the American beachheads and the fierce fighting beforehand had exhausted them. By the start of August, they were running out of food and ammunition, and they had only a handful of tanks left. They withdrew from southern Guam, planning to make a stand in the mountainous central and northern part of the island, and to engage in a delaying action.

Rain and thick jungle made conditions difficult for the Americans, but after an engagement with the main Japanese line of defense around Mount Barrigada from 2 to 4 August, the Japanese line collapsed. On 10 August organized Japanese resistance ended, and Guam was declared secure, but 7,500 Japanese soldiers were estimated to be at large.

Background

Geography

Main article: Geography of Guam

Guam, at 225 square miles (580 km²), is the largest of the Mariana Islands, larger than the other fourteen major islands combined. It is 32 miles (51 km) long from north to south, with a width ranging from 4 to 10 miles (6.4 to 16.1 km) at different points of the island. Along with the other Mariana Islands, Guam was claimed for Spain by Miguel López de Legazpi on 26 January 1565. It became a United States possession after its capture from Spain in June 1898, during the Spanish-American War. Two months later, Spain ceded Guam and the Philippines to the United States for $20 million (equivalent to about $800 million in 2024), and the island became an unincorporated territory. The island was captured by the Japanese on 10 December 1941, following the attack on Pearl Harbor that brought the United States into World War II.

The island is surrounded by coral reefs varying from 20 to 700 yards (18 to 640 m) wide. The northern coastline is fringed with 100-to-600-foot (30 to 183 m) cliffs. Beyond is a limestone plateau, broken up by three hills, Mounts Barrigada, Santa Rosa and Machanao. The southern part of the island is also fringed with reefs and cliffs, but there are breaks in the reefs and the cliffs are lower. The highest peak was Mount Lamlam near the south west coast. Running north of it are Mount Alifan, Tenjo, Chachao and Aluyom. The best beaches lie in between, around Apra Harbor and Agat Bay. Before the war, the harbor was used by United States Navy and PanAm seaplanes; there were no airfields before the Japanese occupation. The Japanese built a 4,500-foot (1,400 m) airfield on the Orote Peninsula, and a 5,000-foot (1,500 m) east of the capital, Agana, was nearing completion in July 1944. Work on a third airfield, at Dededo, had not progressed any further than the area being cleared and staked out. The average temperature was about 87 °F (31 °C) and humidity was 90 percent, with daily rainfall between July and December. In these months, the unpaved roads became all but impassable.

The population of Guam in 1941 was about 23,400, of whom 21,500 were Chamorro people, the indigenous people of the Mariana Islands, who were United States nationals, but not citizens. The garrison consisted of 400 United States Marine Corps and Navy personnel. Most of the population, about 12,500 people, lived in Agana. The Chamorro population suffered considerably during the Japanese occupation of Guam. When it became clear that the island would soon be invaded, Japanese soldiers committed numerous atrocities. The Japanese forcibly relocated most of the island's population to concentration camps in eastern and southern Guam, most notably Manenggon. The camps were without food, shelter or sanitation. It saved them from the American bombardment of the island, although that was not the intent. The catholic priest and local leader Jesus Baza Dueñas was tortured by Japanese interrogators seeking information on George Tweed, and American who had evaded captured when the island was occupied. Dueñas, his nephew Eduardo, and two other men were beheaded on 12 July. They died without knowing that Tweed had been rescued by the destroyer USS McCall two days before.

Strategy

After World War I, the United States had developed a series of contingency plans for the event of a war with Japan known as the Orange plans. These envisaged an advance through the Marshall and Caroline Islands to the Philippines, from whence Japan could be blockaded. The Mariana Islands figured only incidentally in the plans, as they lay north of the direct route between Hawaii and the Philippines. During World War II, the islands attracted the attention of naval and air strategists. At the Casablanca Conference in January 1943, the US and British Combined Chiefs of Staff endorsed a Central Pacific offensive along the lines envisaged in the Orange plans. In his formulation of a Pacific strategy, the Commander in Chief, United States Fleet, Admiral Ernest J. King, specifically mentioned the Mariana Islands as "the key to the situation because of their location on the Japanese line of communication."

King envisaged the Marianas primarily as a naval base, especially for submarines, but another rationale for their capture emerged with the development of the long-range Boeing B-29 Superfortress bomber. From the Mariana Islands, B-29s could reach the most significant industrial targets in Japan, and the air staff planners began incorporating the islands into their long-range plans in September 1943. The Commander in Chief, Pacific Ocean Areas (CINCPOA), Admiral Chester W. Nimitz, produced a campaign plan called Operation Granite, which tentatively scheduled the capture of Mariana Islands of Saipan, Tinian and Guam for 15 November 1944.

By February 1944, there was consideration of advancing the timetable by bypassing Truk and heading directly for Palau or the Marianas after the capture of the Marshall Islands. On 7 March, Nimitz and his Deputy Chief of Staff, Rear Admiral Forrest P. Sherman met with the Joint Chiefs of Staff in Washington, D.C., where they were questioned by the Chief of Staff of the United States Army, General George C. Marshall, and the Chief of Staff to the Commander in Chief, Admiral William D. Leahy. Sherman argued that the neutralization of Truk required the occupation of the Mariana Islands to cut the air route to Truk from Japan. On 12 March, the Joint Chiefs directed Nimitz to neutralize Truk and occupy the Mariana Islands, with a target date of 15 June 1944.

Although Saipan and Tinian were more suitable as long-range bomber bases, since they were closer to Japan, Guam was the most desirable of the Mariana Islands for a naval base, because it had a more adequate water supply and the best anchorage in Apra Harbor. It was decided to invade Saipan first, though, because aircraft based their could then protect Tinian and Guam from air attacks from Japan staging through the Nanpō Islands. The operation to capture the Marianas was codenamed Operation Forager; Guam was codenamed "Stevedore".

Opposing forces

Main article: Battle of Guam (1944) order of battle

United States

Overall command of the operation would be exercised by Nimitz through the commander of the Fifth Fleet, Admiral Raymond A. Spruance. Under Spruance was the commander of the Joint Expeditionary Force (Task Force 51), Vice Admiral Richmond K. Turner and the commander of the Expeditionary Troops (Task Force 56), Lieutenant General Holland M. Smith. Task Force 51 was divided into the Northern Attack Force (Task Force 52), under Turner, which would land and support the troops on Saipan and Tinian, and the Southern Attack Force (Task Force 53), under Rear Admiral Richard L. Conolly, the commander of Amphibious Group 3, which would land and support the troops on Guam. In addition to the two defense battalions, Brigadier General Pedro Augusto del Valle's III Amphibious Corps Artillery had the 1st and 2nd 155 mm Howitzer Battalions and the 7th 155 mm Gun Battalion. A Marine Corps observation squadron, VMO-1, was also assigned.

Senior Navy and Marine Corps commanders. Left to right: Admiral Raymond A. Spruance, Lieutenant General Holland M. Smith, Rear Admiral Richard L. Conolly, Major General Henry L. Larsen and Major General Roy S. Geiger

In Nimitz's preliminary order of 20 March 1944, the task was recapturing Guam was assigned to Major General Roy S. Geiger's I Marine Amphibious Corps, which was renamed the III Amphibious Corps on 15 April. For this operation, Geiger had the 3rd Marine Division, the 1st Provisional Marine Brigade and the 9th and 14th Defense Battalions. The 3rd Marine Division was commanded by Major General Allen H. Turnage. The 1st Provisional Marine Brigade was activated at Pearl Harbor on 22 March and Brigadier General Lemuel C. Shepherd Jr. assumed command on 16 April. The brigade was built around the 4th Marine Regiment on Emirau and the 22nd Marine Regiment, which was in the Marshall Islands; both were ordered to move to Guadalcanal. The 27th Infantry Division was designated the reserve for both the Northern and Southern Attack Forces. The Pacific Ocean Areas reserve was the 77th Infantry Division, which was still in the United States, but under orders to move to Hawaii.

Geiger's headquarters was on Guadalcanal in the Solomon Islands, so, on 29 March, he flew to Pearl Harbor with members of his staff to confer with Spruance, Turner, Smith and Conolly. The plan they drew up, Operation Plan (OpPlan) 1-44, was approved by Smith on 3 April and Turner and Spruance the following day. It called for simultaneous landings on either side of the Orote Peninsula, with a northern attack group under Conolly's command landing the 3rd Marine Division between Adelup Point and the Tatgua River, while a south attack group under Rear Admiral Lawrence F. Reifsnider landed the 1st Provisional Marine Brigade on the beaches between Agat and Bangi Point. The vital Orote Penisula and Apra Habor area would be seized by a double envelopment. That the area was likely to be heavily defended was not overlooked, but in the Battle of Munda Point the tactic of landing elsewhere and fighting through the jungle to the objective had proved to be both slow and costly. Geiger returned to Guadalcanal on 7 April, and Conolly joined him there eight days later, co-locating his headquarters with Geiger's until the command ship USS Appalachian arrived from Pearl Harbor on 27 April.

In addition to the main plan, two alternative plans were developed to cover the contingencies where one of the beaches was found to be too heavily defended or otherwise unsuitable. OpPlan 3-44 provided for landing the entire force in the south between Agat and Facpi Point, while OpPlan 4-44 provided for the 1st Provisional Marine Brigade to land further south, between Bangi and Facpi Points. The landing date, codenamed W-Day to avoid confusion with Saipan's D-Day, was tentatively set for 18 June, three days after the landing on Saipan.

Considering that Guam had been a US possession for over forty years, the quality of information vailable to the US forces about Guam was poor. The Office of Naval Intelligence compiled a 345-page study that was issued in February 1944. The 1:20,000 map issued to the troops contained many broken contour lines, indicating that the area had not been properly surveyed, and the location of roads and tracks, particularly in northern Guam, was frequently inaccurate. Areas marked as bare on the maps turned out to be densely forested, and many low hills were not marked. The Japanese defenders had better maps. Aerial photography was undertaken in April, May and June but persistent cloud cover left many gaps. Offshore, there was uncertainty about how sharply the reefs dropped off on the seaward side. In April, the submarine USS Greenling took a series of oblique images of the beaches. Plaster 1:5000 relief maps with a 2:1 vertical exaggeration of the beach areas were also prepared. When Conolly issued his operation plan for the assault on 17 May, US intelligence estimated that there were between 6,900 and 9,300 Japanese troops of Guam, of whom 2,000 to 2,600 were in airfield construction units.

Japanese

For most of the period of Japanese occupation, the garrison on Guam consisted was the 150 sailors of the 54th Keibitai. In September 1943, indications of an impending American assault on the Gilbert Islands led to a reconsideration of the defense of the island. The 13th Division, which had been serving in China since 1937, was ordered to Guam. An advance party of 300 men sailed for Guam in October 1943, but the main body of the division never followed, as it was diverted to participate in Operation Ichi-Go in southern China.

Japanese infantry and tank dispositions on Guam, 21 July 1944

In February 1944, the 29th Division in Manchuria, under the command of Lieutenant General Takeshi Takashina, was ordered to the Marianas. It embarked from Korea in three ships on 24 February. En route, the Sakito Maru, carrying 4,124 troops, including the division's 18th Infantry Regiment, was torpedoed and sunk by an American submarine, the USS Trout on 29 February. The destroyers escorting the convoy depth charged Trout, which went down with all hands, and took the 1,620 survivors to Saipan. The 1st Battalion remained there; the rest of the regiment, under the command of Colonel Hiko-Shiro Ohashi, continued on to Guam, eventually arriving there on 4 June. The division's 50th Infantry Regiment went to Tinian, while rest of the division, including Colonel Tsunetara Suenaga's 38th Infantry Regiment, reached Guam on 4 March.

The forces on Guam were further reinforced by the 6th Expeditionary force, which embarked from Pusan with 4,700 men from the Kwantung Army's 1st and 11th Divisions. It arrived on Guam on 20 March, where the three battalions of the 11th Division became four battalions (numbered 319th to 322nd) of the 48th Independent Mixed Brigade, under the command of Major General Kiyoshi Shigematsu, and those of 1st Division became the 10th Independent Mixed Regiment, under the command of Colonel Ichiro Kataoka. In June, the 1st Battalion, 10th Mixed Regiment, were sent to Rota. The 3rd Battalion, 38th Infantry Regiment, was also sent there, to make a counter-landing on Saipan, but sea conditions rendered this impossible, and it returned to Guam on 29 June.

The 54th Keibitai was steadily reinforced with coast defence and anti-aircraft units until it reached a strength of about 2,300 in July 1944. It was under Captain Yutaka Sugimoto, the former island commander. In addition, there were two naval construction battalions (Setsueitai), the 217th and 218th, totaling 1,080 men, that had been sent to work on the airfields, but were available for employment in combat. In total, there was about 5,000 naval ground troops and 2,000 men in naval air units. The total Japanese strength on Guam on 18 July was about 18,500 men. Takashina was in command, although his superior, Lieutenant General Hideyoshi Obata, the commander of the Thirty-First Army, who had overall responsibility for the defense of the Mariana Islands, was also on Guam, having been waylaid while returning from Palau to his headquarters on Saipan when the Americans invaded that island.

Takashina positioned most of his troops to protect the airfields and Apra Harbor. The 48th Independent Mixed Brigade was around Agana, with 320th Battalion manning the defenses between Adelup Point and Tumon Bay, the 321st around Agana Bay, and the 322nd around Tumon Bay. The 319th Battalion was held in reserve east of Agana. Takashina placed most of his artillery in this sector, at the disposal of the 48th Independent Mixed Brigade. Naval troops were located around Agana, and Takashina established his headquarters on the Fronte Plateau. The Agat sector was held by the 38th Infantry Regiment, the 54th Keibitai and the 755th Air Group, re-roled as a ground combat unit. Since Takashina could not be certain where the Americans intended to land, other units were disposed around the rest of the island. By early July, he was certain the landing would be on the west coast, so he moved these units there to build up the defenses.

Takashina kept his armor in reserve. The nine light tanks of the 24th Tank Company were inland at Ordot. The 2nd Company, 9th Tank Regiment, with between 12 and 14 tanks, mostly mediums, was in support of the 48th Independent Mixed Brigade. The 1st Company, 9th Tank Regiment, with between 12 and 15 light tanks, was in support of the 38th Infantry Regiment, behind the Agat beaches. In total, there were about 18,500 Japanese troops defending Guam.

Preliminary operations

The landing is postponed

Task Force 53 reached the staging area at Kwajalein on 8 June and after taking on food, fuel and water, set out for the assembly area east of Saipan, which it reached on 15 June. Carrier aircraft from Task Force 58 attacked Guam on 11 and 12 June, and Rear Admiral Walden L. Ainsworth commenced the preliminary bombardment of the Japanese defenses with the battleships USS Pennsylvania and Idaho, the cruiser USS Honolulu and destroyers. Meanwhile, the unexpectedly large Japanese garrison on Saipan and the stubborn resistance it was putting up forced the commitment of 27th Infantry Division to the Battle of Saipan. This deprived the III Amphibious Force of its reserve, it meant that it now became the reserve for the forces on Saipan. Furthermore, the Japanese 1st Mobile Fleet had been detected headed for the Marianas, so a full-scale naval engagement was in prospect. On 16 June, Spruance took the decision to postpone the landing on Guam, and ordered Conolly to take Task Force 53 east, out of harm's way.

The battleship USS New Mexico fires her guns in the pre-invasion bombardment of Guam.

On 25 June, with the Battle of the Philippine Sea won and the situation ashore greatly improved, the III Amphibious Corps was released from its role as reserve, and the ships carrying the 3rd Marine Division (Task Group 53.1) sailed for Eniwetok; those carrying the 1st Provisional Marine Brigade (Task Group 53.2) followed five days later. On 3 July, Spruance held a conference to decide on a new W-Day. The hard fighting on Saipan foretold more of the same on Guam and intelligence reports based on documents captured on Saipan now gave an accurate assessment of Japanese strength. It was decided that more troops were required.

One Regimental combat team, built around the 305th Infantry Regiment, was already on its way, but the conference agreed to postpone the landing until the entire 77th Infantry Division arrived. W-Day was therefore set for 25 July. Neither King nor Nimitz was happy with the delay. It meant that the marines had to spend weeks in cramped quarters on transports, with the inevitable loss of physical condition and combat efficiency. In the event, the main body of the 77th Infantry Division arrived at Eniwetok four days early, so W-Day was advanced to 21 July. With the addition of the 77th Infantry Division, there 37,292 Marines and 19,245 Army troops bound for Guam, so the American attackers outnumbered the Japanese defenders by roughly 3-to-1.

The revised plan called for the 305th Infantry to land on W-Day when ordered by the 1st Provisional Marine Brigade. The rest of the 77th Infantry Division would be a floating reserve until ordered to land on the same beaches by the III Amphibious Corps. The division commander, Major General Andrew D. Bruce, prepared two alternatives plans. One called for the 306th and 307th Infantry Regiments to land near Adelup Point and advance south to Mount Tenjo or southwest to Pago Bay. The other was for a landing on the north coast between Uruno and Ritidian Point. Bruce favored this tactic, and would later use it to great effect in the Battle of Leyte. While the north coast was backed by steep cliffs and dense jungle, the idea was that it would be very lightly defended, and the Japanese would have few reserves to respond. However, the Marines were reluctant to divert the corps reserve for fear that it would be needed on the main beachheads, and they believed that the Japanese did possess reserves. Geiger ultimately responded that it was too late to change the assault plan, but he did defend Bruce to Smith.

Bombardment

One consequence of the postponement of W-Day was that it permitted a prolonged air and sea preliminary bombardment, which turned out to be the longest of any island in the Pacific during the war. On 8 July, Rear Admiral C. Turner Joy re-commenced the bombardment with four heavy cruisers, twelve destroyers and the escort carriers USS Corregidor and USS Coral Sea, in coordination with carrier aircraft from Task Force 58. The main targets were coastal defense and anti-aircraft guns, followed by communications, command posts, warehouses and troop concentrations. Over the following days, the battleships USS New Mexico, Pennsylvania, Idaho, Colorado, California and Tennessee joined in.

Conolly, who had already earned himself the nickname "close-in Conolly" during the Marshall Islands campaign for his insistance on warship conducting shore bombardment from as close to the shoreline as possible, coordinated the effort from Appalachian. Each day, a board of six officers would assign targets based on aerial photographs taken that morning. Geiger was also on board Appalachian and took a close personal interest. In the thirteen days leading up to W-Day, 836 rounds of 16-inch, 5,422 rounds of 14-inch, 3,862 rounds of 8-inch, 2,430 rounds of 6-inch and 16,214 rounds of 5-inch shells pounded the island. In addition, aircraft from Task Forces 53 and 58 dropped 1,131 short tons (1,026 t) of bombs and rockets.

Obstacle clearance

An Underwater Demolition Team (UDT) explosive charge blows up an underwater obstacle off Agat Beach.

Underwater Demolition Team (UDT) 3 arrived off Guam on the high-speed transport USS Dickerson on 16 July and commenced three days and nights of reconnoitering the beaches. In addition to the landing beaches at Agat and Asan, it also conducted surveys of other beaches in order to conceal their intentions from the Japanese. During a daylight reconnaissance of Agat Beach on 15 July, one man was killed by small arms fire when his landing craft became stuck on a coral head. It was discovered that the Japanese beach obstacles consisted of palm log cribs filled with rocks. No land mines were detected, and there was very little barbed wire.

On 17 July, UDT 4 arrived from Guadalcanal on USS Kane and UDT 6 from Eniwetok on USS Clemson. The three teams then began the systematic demolition of the beach obstacles using tetrytol explosives. Some 300 obstacles were removed from the Agat beaches, along with some coral pinnacles blocking a natural channel through the reef to White Beach 1. Another 640 obstacles were blown up at the Asan beaches with 10 short tons (9.1 t) of tetrytol. A Landing Craft Infantry gunboat, LCI(G) 348, one of four providing covering fire and smoke for the UDTs, ran aground 400 to 500 yards (370 to 460 m) off Red Beach 1 and had to pulled off the reef the fleet tug USS Apache.

Battle

On W-Day, 21 July 1944, the fire support ships commenced firing at 05:30. That day, they expended 342 rounds of 16-inch, 1,152 rounds of 14-inch, 1,332 rounds of 8-inch and 13,130 rounds of 5-inch shells, and 9,000 4.5-inch rockets. At 06:15 twelve fighters, nine dive bombers and five torpedo bombers from the aircraft carrier USS Wasp attacked Cabras Island in the first of a series of air strikes by 312 aircraft from Task Force 58 that dropped 124 short tons (112 t) of bombs. The naval bombardment shifted to targets further inland when the troops were 300 yards (270 m) from the beaches, but forty-four fighters strafed the beaches until the first troops were nearly ashore.

The landings followed the same pattern on both the northern and southern beaches. First came nine LCI(G)s that fired 4.5-inch rockets and 20- and 40-mm guns. They were followed by the amphibian tanks (LVT(A)) of the 1st Armored Amphibian Battalion, Landing Vehicles, Tracked, (LVTs) armed with 37 mm gun M6 or 75 mm howitzer motor carriage M8 turrets. Next came the waves of marines in LVTs launched from Landing Ships, Tank, (LSTs) and tanks in Landing Craft, Mechanized, (LCMs). The LVTs were able to cross the reef and disembark their troops on the beach; the LCMs grounded on the reef and the tanks drove through the shallow water. Only the first waves of infantry were in LVTs; succeeding waves arrived in assault transports and were loaded onto Landing Craft, Vehicle, Personnel, (LCVPs) that carried them to the reef, where they transferred to LVTs from earlier waves that brought them to the beach.The first LVT(A)s reached the beaches at 08:28, two minutes ahead of schedule.

Northern beachhead

Beach sketch - northern sector

Scheme of maneuver, Asan beachhead

Despite the intense shore bombardment, Japanese mortars and artillery opened up, and nine of the 3rd Marine Division's LVTs were knocked out.

Despite the obstacles, on 21 July the American forces landed on both sides of the Orote Peninsula on the western side of Guam, planning to secure Apra Harbor. The 3rd Marine Division landed at Asan near Agana to the north of Orote at 08:29, and the 1st Provisional Marine Brigade landed near Agat to the south. Japanese artillery sank 30 U.S. LVTs and inflicted heavy casualties on the landing troops, especially of the 1st Provisional Marine Brigade, but by 09:00 Marines and tanks were ashore at both beaches.

Asan's Green and Blue Beaches stretch from Asan town (left center) to Asan Point (lower right)

Scene on Asan Beach an hour and a half after the first landings, 21 July 1944. A field dressing station is in operation in the foreground. Note LVTs and M-4 tanks.

Southern beachhead

By nightfall, the Marines and soldiers of the 77th Infantry Division had established beachheads about 6,600 feet (2,000 m) deep. The 77th Infantry Division had a more difficult landing on 23–24 July. Lacking amphibious vehicles, they had to wade ashore from the edge of the reef where the landing craft dropped them off. The men stationed in the two beachheads were pinned down by heavy Japanese fire, making initial progress inland quite slow. Supply was very difficult for the landing troops on Guam in the first days of the battle; landing ships could not come closer than the reef, several hundred yards from the beach, and amphibious vehicles were scarce.

The 1st Provisional Brigade blocked off the Orote Peninsula on 25 July, and that same night Takashina counterattacked, coordinated with a similar attack against the 3rd Division to the north. The next day, Obata reported, "our forces failed to achieve the desired objectives." Takashina was killed on 28 July, and Obata took over command. On 28 July the two beachheads were linked, and by 29 July the Americans had secured the peninsula.

Southern beach sketch

Scheme of maneuver, Agat beachhead

Agat Invasion Beach, 21 July 1944

Final operations

The Japanese counterattacks against the American beachheads, as well as the fierce fighting, had exhausted the Japanese. At the start of August, they were running out of food and ammunition, and they had only a handful of tanks left. Obata withdrew his troops from southern Guam, planning to make a stand in the mountainous central and northern part of the island, "to engage in delaying action in the jungle in northern Guam to hold the island as long as possible".

After ensuring that no significant Japanese forces operated in the southern portion of Guam, Marine Major General Roy S. Geiger started an offensive north with the 3rd Marine Division on the left flank and the 77th Infantry Division on the right, liberating Agana on the same day. The Tiyan Airfield was captured on 1 August.

Rain and thick jungle made conditions difficult for the Americans, but after an engagement with the main Japanese line of defense around Mount Barrigada from 2 to 4 August, the Japanese line collapsed. The 1st Provisional Brigade formed up on the left flank of the 3rd Marine Division on 7 August because of the widening front and continued casualties, in an effort to prevent the Japanese from slipping through gaps in the line. The Japanese had another stronghold at Mount Santa Rosa, which was secured by US forces on 8 August.

On 10 August organized Japanese resistance ended, and Guam was declared secure, but 7,500 Japanese soldiers were estimated to be at large. The next day, Obata committed ritual suicide at his headquarters on Mount Mataguac after he had sent a farewell message to Japan.

Aftermath

U.S. Marines show their appreciation to the U.S. Coast Guard.

Three Marine officers of an amphibian tractor battalion who took part in the invasion of Guam (left to right): Major Erwin F. Wann, Major W. W. Butler, and Lt. Colonel Sylvester Stephens

A few Japanese soldiers held out in the jungle for years after the fighting on Guam. On 8 December 1945, three U.S. Marines were ambushed and killed. Sergeant Masashi Itō surrendered on 23 May 1960, after the last of his companions was captured. On 24 January 1972, Sergeant Shoichi Yokoi was discovered by hunters on the island. He had lived alone in a cave for 28 years, near Talofofo Falls.

Guam was turned into a base for Allied operations after the battle. Five large airfields were built by the Navy Seabees and African American Aviation Engineering Battalions. Army Air Forces B-29 bombers flew from Northwest Field and North Field on Guam to attack targets in the Western Pacific and on mainland Japan.

Liberation Day continues to be celebrated on Guam on the anniversary of the US landing, every 21 July.

Unit awards

Navy Unit Commendation:

• 1st Provisional Marine Brigade, 21 July to 10 August 1944

Medal of Honor recipients

Four Medal of Honor recipients of the Battle of Guam:

• Captain Louis H. Wilson Jr., USMC
• Private First Class Leonard F. Mason, USMC (posthumous)
• Private First Class Luther Skaggs Jr., USMC
• Private First Class Frank P. Witek, USMC (posthumous)

See also

• Agana race riot – Violent confrontation between white U.S. Marines and black U.S. sailors
• Return to Guam, 1944 documentary and propaganda film about the battle
• The War in the Pacific National Historical Park

References

• Anderson, Charles R. (2021). Western Pacific (PDF). U.S. Army Campaigns of World War II. Washington, D.C.: United States Army Center of Military History. ISBN 978-0-16-045116-4. OCLC 31215025. CMH Pub 72-29. Retrieved 9 June 2025.
• Burns, James MacGregor (1990) [1946]. Guam: Operations of the 77th Division (PDF). American Forces in Action series. Washington, D.C.: United States Army Center of Military History. OCLC 1291353. CMH Pub 100-5. Retrieved 9 June 2025.
• Cate, James (1953). "The Twentieth Air Force and Matterhorn". In Craven, Wesley Frank; Cate, James (eds.). The Pacific: Matterhorn to Nagasaki, June 1944 to August 1945 (PDF). The Army Air Forces in World War II. Vol. V. Chicago: University of Chicago Press. pp. 3–178. Archived (PDF) from the original on 9 May 2021. Retrieved 26 June 2023.
• Crowl, Philip A. (1960). Campaign in the Marianas (PDF). United States Army in World War II, The War in the Pacific. Center of Military History, United States Army. OCLC 1049152860. CMH Pub 5-7. Archived from the original (PDF) on 9 December 2023. Retrieved 13 March 2024.
• Dyer, George Carroll (1969). The Amphibians Came to Conquer: The Story of Admiral Richmond Kelly Turner (PDF). Vol. II. Washington, D.C.: Department of the Navy. OCLC 1023102368. Archived (PDF) from the original on 10 April 2023. Retrieved 15 March 2024.
• Estes, Kenneth W. (2000). Marines Under Armor: The Marine Corps and the Armored Fighting Vehicle, 1916–2000. Annapolis, Maryland: Naval Institute Press. ISBN 1-55750-237-4. OCLC 43648651.
• Gruhl, Werner (2007). Imperial Japan's World War Two: 1931–1945. New Brunswick: Transaction Publishers. ISBN 978-0-7658-0352-8. OCLC 76871604.
• Hallas, James H. (2025). Guam: The Battle of an American Island in World War II. Essex, Connecticut: Stackpole Books. ISBN 978-0-8117-7689-9. OCLC 1440217490.
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• Isely, Jeter A.; Crowl, Philip A. (1951). U.S. Marines and Amphibious Warfare: Its Theory and Practice in the Pacific. Princeton, New Jersey: Princeton University Press. doi:10.1515/9781400879465.
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• Morison, Samuel Eliot (1953). New Guinea and the Marianas, March 1944 – August 1944. History of United States Naval Operations in World War II. Vol. VIII. Boston: Little Brown. OCLC 10926173.
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Further reading

• Gailey, Harry (1988). The Liberation of Guam 21 July – 10 August. Novato, California: Presidio Press. ISBN 978-0-89141-651-7.
• Hatashin, Omi (2009). Private Yokoi's War and Life on Guam, 1944–72: The Story of the Japanese Imperial Army's Longest WWII Survivor in the Field and Later Life. Honolulu: University of Hawaii Press. ISBN 978-1-905246-69-4.

External links

• Battle for the Mariana Islands on YouTube
• "The Marianas and the Great Turkey Shoot", World War II Database.
• Keene, R.R. "Wake up and die, Marine!". Leatherneck Magazine.
• Photos from the Liberation of Guam Archived 6 August 2017 at the Wayback Machine The Real Revo
• A film clip Allies' Study: Post-War Security, etc. (1944) is available for viewing at the Internet Archive
• Pacific War Museum National Park Service site