Mariana & palau
American naval forces attacked the Mariana and Palau Islands in 1944 and destroyed Japan’s defensive perimeter to gain proximity to Tokyo. The campaign for the Mariana and Palau Islands from June to November 1944 became a crucial turning point in the Pacific War which demonstrated the superior strength of American carriers, battleships, and amphibious units. Through the Battle of the Philippine Sea, known as the “Great Marianas Turkey Shoot,” to the intense battles for Saipan, Tinian, Guam, and Peleliu American forces established essential B-29 bomber bases and established their control over the Pacific. The Fleet of Freedom initiative presents Charles Jones' collection of WWII model warships that precisely reconstructs the prominent ships of the U.S. Fifth Fleet which advanced through Japan's core defenses by demonstrating naval strength along with air power and sophisticated logistical operations. Examine the significant military successes and costly sacrifices that led to the victory of 1945.
Introduction to mariana & palau: central pacific offensive
During 1944 the United States Pacific Fleet launched an unrelenting offensive in the Central Pacific against the Mariana and Palau Islands which destroyed Japan’s defensive perimeter and positioned American troops within reach of Japan's home territory. Between June and November 1944 during the Mariana and Palau Islands Campaign the United States Navy demonstrated its superior capabilities in carriers, battleships and amphibious operations which became a significant turning point in the Pacific War. Through the decisive Battle of the Philippine Sea and the difficult invasions of Saipan, Tinian, Guam and Peleliu the offensive captured vital airfields for B-29 bombers ensuring American dominance in the Pacific. The Pacific Fleet demonstrated its ability to project power over extensive distances and penetrate Japan’s inner defenses through a combination of naval strength, air domination and logistical mastery.
mariana & palau ships
The Mariana’s & Palau campaign centered on aircraft carriers where their support vessels and escorts played a decisive role in determining the battle's outcome. The following list summarizes the principal ships engaged in the battle as detailed by Chesneau, Whitley, and Bagnasco.
historical & strategic Context
By mid-1944 the US took control of the Pacific strategic direction. Japan's naval and air capabilities diminished after winning Midway in 1942 and Guadalcanal from 1942 to 1943 while American forces used the Gilbert and Marshall Islands campaign from 1943 to 1944 to position themselves for attacks on Japan's central defensive perimeter. Saipan, Tinian, and Guam formed the Mariana Islands which held strategic importance because they were located only 1,500 miles from Tokyo.
The conquest of these islands would establish launch points for B-29 Superfortress bombers to hit Japan’s industrial core and enable assaults on the Philippines and further territories. The Palau Islands, especially Peleliu, received targeting to protect the eastern boundary of the Philippine campaign plans.
During 1944 Admiral Chester W. Nimitz led the U.S. Pacific Fleet which functioned as an unstoppable juggernaut. A massive logistical network supported the U.S. Pacific Fleet's fast carrier task forces, battleship squadrons, and amphibious fleets in carrying out operations across the Pacific. Vice Admiral Marc Mitscher led Task Force 58 as the fleet’s main unit with 15 carriers and more than 900 aircraft together with powerful battleships, cruisers, and destroyers for defense. Admiral Soemu Toyoda commanded Japan’s diminished yet dangerous Combined Fleet which faced them. The moment had arrived for a decisive battle that would decide Japan's Pacific empire's future.
Operation Forager: Conquest of the Mariana Islands
The June 1944 Operation Forager focused on capturing Saipan, Guam, and Tinian to create bases from which Japan could be bombed. Saipan was invaded on June 15 marking the start of the campaign which included Guam on July 21 and Tinian on July 24. Vice Admiral Marc Mitscher commanded Task Force 58 while Admiral Raymond A. Spruance led the Fifth Fleet to deploy over 127,000 troops alongside 600 ships and 900 aircraft. Japan deployed around 71,000 troops to defend the islands and they fought vigorously in key areas such as Saipan’s Mount Tapotchau and Guam’s Fonte Plateau. During the Battle of the Philippine Sea on June 19-20 Japan suffered a major defeat which impaired their carrier and land-based air forces and prevented them from challenging U.S. naval power earning the battle the nickname “Great Marianas Turkey Shoot.” The Marianas were secured by August 1944 and allowed construction of airfields for B-29 bombers leading to strategic strikes against Japan including the nuclear bombings of Hiroshima and Nagasaki.
Operation Stalemate: Securing the Palau Islands
Operation Stalemate launched in September 1944 focused on taking Peleliu and Angaur in the Palau Islands to safeguard the American flank during the forthcoming Philippines operation. Approximately 11,000 Japanese defenders commanded by Lieutenant General Sadae Inoue confronted U.S. Marine and Army units including the 1st Marine Division and the 81st Infantry Division. The 60-day Battle of Peleliu witnessed intense fighting at the Umurbrogol pocket as Japanese defenders hidden in caves and bunkers caused severe U.S. troop casualties. The 322nd Regimental Combat Team faced tough resistance from interconnected cave fortifications located in “the Bowl” valley during the Battle of Angaur from September 17 to October 22. The Allies secured the Palaus by November 1944 after heavy losses of 8,125 American soldiers killed or missing and more than 67,000 Japanese casualties but the main Japanese garrison on Koror did not capitulate until August 1945. Admiral William F. Halsey Jr. later argued the campaign was unnecessary but recognized its value in providing combat experience to the 81st Infantry Division.
Strategic Impact and Legacy
The Allied war effort progressed substantially through the Mariana and Palau Islands Campaign. The Allied seizure of the Marianas islands broke through Japan’s defense lines, disrupted their supply routes, and allowed for the establishment of B-29 airfields that targeted Japan’s industrial regions. Although the Palau victories demanded high expenditure of resources they protected the U.S. flank for Philippines operations beginning in October 1944. The severe Japanese resistance became clear through the 322nd RCT's 80% casualty rate on Angaur and the extended battle at Peleliu which informed U.S. military planning thereafter. Granite II's success showed how well the U.S. island-hopping strategy worked to move the Allies nearer Japan and prepare for the last Pacific battles.
Tactical Challenges and Long-Term Impact
The Mariana and Palau Islands Campaign showcased intense tactical challenges. On Peleliu, the Umurbrogol pocket’s cave defenses forced U.S. Marines into prolonged combat, while Angaur’s “the Bowl”—a valley of interconnected caves—saw the 322nd RCT endure an 80% casualty rate. These battles informed U.S. planning for future Pacific invasions. The campaign’s airfields, particularly on Tinian, enabled B-29s to launch nuclear strikes on Hiroshima and Nagasaki in August 1945, hastening Japan’s surrender.
The Battle of the Philippine Sea: The Great Marianas Turkey Shoot
The initial phase of the Mariana and Palau Islands Campaign began with the Battle of the Philippine Sea occurring on June 19–20, 1944 and this massive carrier battle demonstrated the U.S. Navy’s superiority. The Japanese initiated Operation A-Go to destroy the U.S. fleet through carrier-based and land-based aviation as American troops prepared their invasion of Saipan. Vice Admiral Jisaburo Ozawa led the Japanese First Mobile Fleet as they deployed nine carriers with 450 aircraft while receiving support from land-based planes based in the Marianas.
The Japanese aircraft initiated their assault on Task Force 58 with wave attacks on June 19. American radar and fighter direction systems which had been refined through years of combat showed devastating effectiveness. American pilots flying F6F Hellcat fighters stopped Japanese attacks during the “Great Marianas Turkey Shoot” by destroying many planes while the Americans suffered few losses. Japanese pilots who entered battle unprepared and hastily replaced earlier losses proved unable to stand against well-trained American forces.
Mitscher’s carriers launched their counterattack on June 20 when they located Ozawa’s fleet late in the afternoon. American planes embarked on a "mission beyond darkness" to attack at extraordinary distances which resulted in sinking the carrier Hiyo and damaging additional ships. During earlier phases of the battle, Japanese carriers Shokaku and Taiho were sunk by submarine attacks. By the end, Japan suffered catastrophic losses: Japan endured the destruction of three aircraft carriers and more than 600 planes while the Americans lost only 123 planes. The Battle of the Philippine Sea damaged Japan’s naval air power beyond recovery which enabled U.S. air forces to maintain dominance for the rest of the campaign. The Pacific Fleet’s aircraft carriers showed their unparalleled ability to control the skies and oceans which prepared for future beachhead attacks.
The Saipan Operation broke through Japan's central defensive lines
The Marianas Campaign began with the invasion of Saipan which started on June 15, 1944, marked a critical turning point in the Pacific Theater of World War II. As the first major objective of Operation Forager, the U.S. campaign to capture the Mariana Islands, Saipan’s conquest brought American forces within striking distance of Japan’s home islands, enabling strategic bombing campaigns and weakening Japan’s defensive perimeter. Saipan hosted formidable defenses and 30,000 Japanese troops led by Lieutenant General Yoshitsugu Saito who were committed to defending the island. The U.S. Fifth Fleet commanded by Admiral Raymond Spruance delivered intense naval bombardments from battleships and cruisers against Japanese positions throughout the days before the planned landings. The 2nd and 4th Marine Divisions alongside the Army’s 27th Infantry Division assaulted the beaches during D-Day with the support of an extensive amphibious fleet consisting of transports, landing craft, and escort ships.
The Pacific Fleet’s role was critical. The battleships Tennessee and California used their naval guns to destroy coastal fortifications while carrier-based aircraft delivered close air support. Underwater demolition teams removed beach obstacles while logistical ships transported soldiers and equipment through enemy fire. American forces successfully captured Saipan on July 9 despite intense opposition that included nighttime attacks and banzai charges. The battle concluded with the complete destruction of the Japanese garrison force which resulted in over 29,000 fatalities including Japanese commander Saito who ended his own life. Thousands of Japanese civilians died tragically while many others committed mass suicides due to manipulative propaganda.
Strategic Importance
Saipan’s capture was a cornerstone of Admiral Ernest J. King’s Central Pacific offensive, designed to pierce Japan’s inner defenses. The island’s airfields, particularly Aslito Field (later renamed Isely Field), provided bases for B-29 Superfortress bombers, which could reach Tokyo and other key Japanese cities within their 1,600-mile combat radius. This capability shifted the war’s momentum, exposing Japan’s industrial and civilian centers to sustained aerial bombardment.
The battle also triggered the Battle of the Philippine Sea, a decisive naval engagement that crippled Japan’s carrier-based airpower, further tilting the balance in favor of the Allies. American forces established Saipan as a base for B-29 bombers that launched air raids on Japan starting in November 1944. The Japanese government faced a political crisis after the fall of Saipan which resulted in Prime Minister Hideki Tojo's resignation. The Pacific Fleet proved its logistical skill and amphibious capabilities by delivering and maintaining an invasion force operating 3,000 miles from its main bases.
The Invasion of saipan
The U.S. assault on Saipan began with an intensive two-day naval bombardment, followed by landings by the 2nd and 4th Marine Divisions and the Army’s 27th Infantry Division under Lieutenant General Holland Smith. Over 60,000 American troops, supported by more than 500 ships and 150 tanks, faced a formidable Japanese force of nearly 32,000, commanded by Lieutenant General Yoshitsugu Saitō. Despite fierce resistance, including night counterattacks and artillery barrages from well-concealed positions, the Americans established a beachhead and gradually pushed inland.
Tactical Innovations in the Saipan Invasion
During the Saipan invasion, U.S. forces employed advanced tactics to overcome Japanese defenses. Over 150 M4 Sherman tanks supported infantry, targeting fortified positions, while flamethrower-equipped M3 Stuart tanks, nicknamed “Satans,” proved vital in destroying pillboxes and cave defenses. These innovations, coordinated with naval bombardments and air support, enabled American troops to push through Saipan’s challenging terrain and secure the island by July 9, 1944.
Challenges and Terrain
Saipan’s diverse terrain, including volcanic ridges, Mount Tapotchau, and dense sugar cane fields, posed significant obstacles. The cane fields concealed Japanese defenders, complicating American advances, while urban areas and a substantial civilian population—approximately 26,000 to 28,000, mostly Japanese subjects—added complexity to the campaign. The island’s defenses, bolstered by coastal guns and over 500 land-based aircraft, were designed to repel invaders and support Japan’s plan for a decisive naval battle.
Turning Points and Costs
By late June, American forces had reduced Japanese resistance significantly, prompting Saitō to retreat to a final defensive line in central Saipan. The campaign culminated in a devastating Japanese gyokusai attack, where at least 3,000 soldiers perished, followed by the tragic suicide of around 1,000 civilians. The battle resulted in over 46,000 military casualties, including 6,000 American and 32,000 Japanese losses, and at least 8,000 civilian deaths. These heavy losses informed the “Saipan ratio,” shaping American planning for future invasions, including projections for the potential invasion of Japan.
saipan’s Legacy
Saipan’s fall had profound consequences. It led to the resignation of Japanese Prime Minister Hideki Tōjō and forced Japan’s leadership to acknowledge publicly that the war was turning against them. The island became a vital base for B-29 operations, with the first strategic bombing mission against Tokyo launched from Saipan on November 24, 1944. The victory underscored the effectiveness of the U.S. island-hopping strategy and set the stage for subsequent operations in the Marianas and beyond, bringing the Allies closer to victory in the Pacific.
Tinian and Guam: Consolidating the Marianas
After capturing Saipan the United States military moved its operations to Tinian which lay only three miles across the water. The 2nd and 4th Marine Divisions conducted landings on July 24, 1944 with naval forces that previously secured Saipan to provide support. Despite strong resistance from Tinian’s 9,000 Japanese defenders the island was successfully secured by August 1. The battleships executed accurate bombardments and Hellcats attacked Japanese positions while naval gunfire and carrier air support proved decisive once more. The flat terrain of Tinian allowed for efficient airfield construction which served as the critical launch site for B-29 bombers that delivered atomic payloads to Hiroshima and Nagasaki.
The U.S. territory of Guam fell to Japan in 1941 before becoming the next target for military operations. The 3rd Marine Division and 1st Provisional Marine Brigade along with the Army’s 77th Infantry Division completed their landing on July 21, 1944 after enduring heavy naval bombardment. Japanese defenses were destroyed by Pacific Fleet firepower but rugged terrain and determined resistance delayed progress.
Guam fell under American control on August 10 after a battle which resulted in 18,000 Japanese soldiers killed and 7,000 American soldiers dead or wounded. The capture of Guam transformed it into an essential staging point for further military operations and represented a symbolic triumph for the United States.
Peleliu: The Costly Victory
During the Palau Islands Campaign which overlapped with the Marianas operation Peleliu was targeted to safeguard the flank for future Philippine invasion operations. The 1st Marine Division arrived on Peleliu on September 15, 1944 with assistance from Vice Admiral Jesse Oldendorf's naval task force. The Pacific Fleet’s battleships and cruisers executed a fierce bombardment yet the 10,000 Japanese defenders who had fortified themselves in caves and bunkers remained ready for combat. The fight turned into a bloody marathon as Marines endured continuous counteroffensives while battling harsh environments within Peleliu’s coral ridges.
The destroyers and escort carriers were essential because they delivered gunfire support and protected the skies. The Japanese approach of dragging out battles while holding strong defensive positions led to severe losses in their forces. Military forces declared Peleliu secure on November 27, 1944 yet combat persisted until 1945. While the 1st Marine Division sustained 6,500 casualties during combat operations at Peleliu the Army's 81st Infantry Division lost 3,000 additional soldiers while bolstering Marine efforts. Japanese losses exceeded 10,000. The expensive operation at Peleliu led to discussions about its strategic importance because the island's airfield turned out to have minimal impact on subsequent military actions. The Pacific Fleet demonstrated its operational range by maintaining an amphibious assault capability in such a distant area.
The Pacific Fleet’s Dominance
During the Mariana and Palau Islands Campaign the U.S. Pacific Fleet demonstrated its unmatched strength. Task Force 58's carriers used their Hellcat aircraft and skillful pilots to control the aerial domain while battleships and cruisers provided powerful bombarding attacks. With extensive logistical support from transports, tankers, and supply ships, amphibious forces carried out intricate invasions with exacting precision. The fleet achieved extraordinary logistical feats through meticulous planning and execution by sustaining fuel, ammunition, and supplies over thousands of miles.
The campaign’s success came at a cost. The battle in the Marianas resulted in over 14,000 American casualties and the battle at Peleliu produced similarly devastating losses. The Japanese military suffered catastrophic losses as more than 60,000 soldiers and numerous planes were annihilated. The Pacific Fleet demonstrated superior capacity to sustain operations despite casualties while Japan faced severe depletion of its resources. The United States' acquisition of bases by November 1944 allowed B-29 bombers to reach Japan for subsequent firebombings & atomic attacks in 1945.
Decision Matrix: The Marianas & palau islands
| Decision Factor | Allied Decision | Outcome | Japanese Decision | Outcome |
|---|---|---|---|---|
| Objective Focus | Capture Mariana Islands (Saipan, Guam, Tinian) to establish B-29 bases for bombing Japan. | Successful landings and airfield construction enabled strategic bombing of Japan. | Defend Marianas to protect inner defense perimeter and engage U.S. fleet in decisive battle. | Failed to hold Marianas; loss of Saipan led to political crisis in Japan. |
| Use of Naval Forces | Deploy Task Force 58 with multiple carriers to support invasions and engage Japanese fleet. | Decisive victory at Battle of Philippine Sea ("Great Marianas Turkey Shoot") crippled Japanese carrier airpower. | Commit Mobile Fleet (carriers, battleships) to counter Allied invasion. | Heavy losses of aircraft and pilots; carriers retreated, leaving islands undefended. |
| Risk Tolerance | Invade Peleliu despite rugged terrain to secure eastern flank for Philippines campaign. | High casualties but neutralized Japanese airfields; strategic value debated post-war. | Defend Peleliu with entrenched positions and delay tactics to inflict maximum casualties. | Prolonged resistance caused high U.S. losses but failed to prevent Allied advance. |
| Coordination and Communication | Integrated naval, air, and ground forces for amphibious assaults; effective use of intelligence. | Coordinated attacks overwhelmed Japanese defenses across multiple islands. | Fragmented command structure; lack of naval support after Philippine Sea defeat. | Isolated garrisons unable to receive reinforcements or supplies, leading to defeat. |
| Flexibility in Tactics | Adapted amphibious tactics for varied terrains; shifted focus to Philippines after Marianas. | Secured key objectives and maintained momentum in Pacific advance. | Rigid defense strategies; continued reliance on banzai charges and fixed fortifications. | High casualties for minimal gains; failed to adapt to Allied technological superiority. |
Key Takeaways
Naval Supremacy: The Battle of the Philippine Sea showcased U.S. carrier warfare dominance while the "Great Marianas Turkey Shoot" destroyed Japan’s air power and ensured air control for the campaign.
Amphibious Prowess: Through coordination of naval bombardment air support and amphibious landings the Pacific Fleet succeeded in capturing the heavily defended islands of Saipan Tinian Guam and Peleliu.
Strategic Impact: The Marianas served as launch pads for B-29 bombers which allowed direct assaults on Japan’s mainland and hastened the conclusion of the war. Despite its heavy price, Peleliu operation protected the Philippines' eastern defenses.
Logistical Triumph: The fleet demonstrated logistical sophistication by maintaining operations across huge distances which played a crucial role in determining the Pacific War’s outcome.
Human Cost: The severe loss of life at Peleliu demonstrated the harsh realities of island combat in the Pacific while igniting discussions about strategic military planning.
| Battle | U.S. Casualties | Japanese Casualties | Civilian Deaths |
|---|---|---|---|
| Saipan | 6,000 | 32,000 | 8,000 |
| Guam | 7,000 | 18,000 | - |
| Tinian | 389 | 5,000+ | 4,000 |
| Peleliu | 9,500 (6,500 Marines + 3,000 Army) | 10,000+ | - |
| Angaur | Included in Palau | Included in Palau | - |
final thoughts
The 1944 Mariana and Palau Islands Campaign represented a crucial turning point in the Pacific War as the U.S. Pacific Fleet successfully penetrated Japan’s inner defenses. The campaign demonstrated how the fleet transformed into a powerful force that could effectively deploy military power through carrier groups and amphibious landings alongside traditional battleships. The sacrifices of American forces at Saipan, Tinian, Guam and Peleliu created conditions for Japan’s eventual defeat by enabling American forces to reach the islands near Japan. The men who served in the Pacific Fleet faced a grueling test of courage and endurance during the campaign. Their success transformed the direction of the Pacific War and prepared the way for victory that would come in 1945. The Central Pacific Offensive stands as an essential part of U.S. Navy history which continues to resonate today.