Introduction. GORDON R. SULLIVAN General, United States Army Chief of Staff

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2 Introduction Word War II was the argest and most vioent armed confict in the history of mankind. However, the haf century that now separates us from that confict has exacted its to on our coective knowedge. Whie Word War II continues to absorb the interest of miitary schoars and historians, as we as its veterans, a generation of Americans has grown to maturity argey unaware of the poitica, socia, and miitary impications of a war that, more than any other, united us as a peope with a common purpose. Highy reevant today, Word War II has much to teach us, not ony about the profession of arms, but aso about miitary preparedness, goba strategy, and combined operations in the coaition war against fascism. During the next severa years, the U.S. Army wi participate in the nation s 50th anniversary commemoration of Word War II. The commemoration wi incude the pubication of various materias to hep educate Americans about that war. The works produced wi provide great opportunities to earn about and renew pride in an Army that fought so magnificenty in what has been caed the mighty endeavor. Word War II was waged on and, on sea, and in the air over severa diverse theaters of operation for approximatey six years. The foowing essay is one of a series of campaign studies highighting those strugges that, with their accompanying suggestions for further reading, are designed to introduce you to one of the Army s significant miitary feats from that war. This brochure was prepared in the U.S. Army Center of Miitary History by Chares R. Anderson. I hope this absorbing account of that period wi enhance your appreciation of American achievements during Word War II. GORDON R. SULLIVAN Genera, United States Army Chief of Staff

3 Western Pacific 15 June September 1945 By the summer of 1944 American forces in the Pacific had estabished two routes of attack in their drive toward Japan. In the Centra Pacific Navy and Marine Corps units, with Army assistance, were isand-hopping westward from Hawaii, taking the Gibert Isands in a costy campaign in November 1943 and the Marsha Isands in January February In the South and Southwest Pacific Areas, Army units, with Navy and Marine Corps support, had taken Guadacana and Bougainvie in and, operating with Austraian forces, had ceared northeast New Guinea and the Hoandia area of Netherands New Guinea by May These victories brought American forces to the inner defense ine of the Japanese Empire. In deciding where to breach that ine, the Aies ooked for a pace that woud not ony puncture Japanese confidence but provide anchorages for nava support of subsequent operations and air bases for strikes against enemy industria and miitary instaations. The best isands for these purposes ay in the Western Pacific: the Marianas and the Paaus. Strategic Setting When United States Army and Navy forces began pushing west into the Pacific after the disaster at Pear Harbor, they had their utimate objective, the Japanese home isands, ceary in mind. However, they acked any detaied ist of preiminary objectives that woud bring them to the enemy s shores. Each isand victory raised anew the question of the next intermediate goa. By the summer of 1944 the Aies faced a number of choices in the Pacific. They coud continue directy west from Hawaii on a Centra Pacific thrust that had just won them the Marsha Isands. They coud continue toward the Phiippines on a Southwest Pacific course that had recenty won New Guinea. Or they coud continue operations aong both of these axes simutaneousy. During 1943 infuentia personaities in the U.S. Army and Navy ined up behind different strategies for the Pacific. The Chief of Nava Operations, Admira Ernest J. King, favored focusing Aied efforts against Japan in a thrust westward from Hawaii. Seconded by Admira Chester W. Nimitz, Commander in Chief, Pacific Ocean Areas and Pacific Feet, King argued that his Centra Pacific strategy aso repre-

4 THE PACIFIC AND ADJACENT THEATERS Japanese Limit of Contro Mies at the Equator UNION OF SOVIET SOCIALIST REPUBLICS 80 USSR 100 MONGOLIA MANCHURIA 40 C H I N A KOREA TIBET NEPAL I N D I A 20 0 BHUTAN AUG 42 JUN 42 INDIAN OCEAN FORMOSA BURMA Hong Kong SOUTHWEST PACIFIC AREA LUZON SOUTH THAILAND PHILIPPINES FRENCH CHINA INDOCHINA SEA MINDANAO MALAYA SUMATRA SARAWAK Singapore BORNEO NETHERLANDS INDIES JAVA NORTH BORNEO CELEBES PALAU ISLANDS AUG CENTRAL P 42 J A Iw JU C JUN NEW G PA MAY 42 SOUTHEAST ASIA COMMAND 20 AUSTRALI

5 USSR AUG 42 MAY B ER Attu A L E U IN T I G A N SEA I S L A N D S P A N NORTH PACIFIC AREA CENTRAL PACIFIC AREA PACIFIC JUN o Jima MARIANA ISLANDS OCEAN Wake Batte of Midway MIDWAY ISLANDS Pear Harbor Strike HAWAIIAN ISLANDS 20 N 44 Guam Truk MARSHALL ISLANDS AUG 42 AROLINE ISLANDS ACIFIC AREA BISMARCK ARCHIPELAGO 42 INEA PUA Batte of Cora Sea SOLOMON ISLANDS Guadacana Makin Tarawa GILBERT ISLANDS MAY 42 ELLICE ISLANDS NEW HEBRIDES FIJI ISLANDS SOUTH PACIFIC AREA 0 CORAL SEA A NEW CALEDONIA TONGA ISLANDS

6 sented the most direct route to the Phiippines and woud, at the same time, pace American forces on the enemy ine of communications between Japan and the oi-rich East Indies. King repeated his Centra Pacific proposa at the Trident Conference in Washington in May, but it was neither approved nor rejected. King s major opponent was Genera Dougas MacArthur, the Aied Southwest Pacific theater commander. MacArthur agreed on the need to return to the Phiippines but not via the Marshas and Marianas. Instead, he proposed a Southwest Pacific strategy: an extension of his own command s operations in New Guinea, which woud push Aied forces westward through Morotai and then northward into the Phiippines. A series of Aied panning conferences in 1943 faied to resove the issue. The strong identification of each strategy with a different miitary service Centra Pacific with the U.S. Navy and Southwest Pacific with the U.S. Army tended to undermine an unbiased appraisa of either course of action and to encourage the potentiay dangerous pursuit of both with inadequate resources. Finay, toward the end of 1943, a technoogica deveopment began to infuence the issue. The Army Air Forces announced the imminent appearance of a new ong-range bomber, the B 29. The new weapon strengthened the Centra Pacific strategy, since the isand chain particuary desired by Admira King the Marianas ay 1,270 mies from Tokyo, comfortaby within the 1,500-mie radius of the new aircraft. At the second Cairo Conference in December 1943 the Aies thus approved seizure of the Marianas, tentativey schedued for October Subsequent operations aong this axis woud incude seizure of the Paaus to secure the fank for the turn northwest into the Phiippines. Athough these decisions gave priority to the Centra Pacific strategy, they did not amount to a rejection of MacArthur s Southwest Pacific proposas. In fact, the Joint Chiefs of Staff reaffirmed in March 1944 that the advance toward Japan woud continue on both the Centra and Southwest Pacific axes. At the same time, unexpectedy rapid success in the Marshas aowed panners to advance the assaut on the Marianas from October to June. Operations Located some 3,300 mies west of Hawaii and 1,400 mies east of the Phiippines, the Marianas archipeago consists of fifteen vocanic isands. The Marianas aready had a ong history of foreign domination before the Japanese arrived to incorporate the archipeago and its 6

7 Chamorro peope into a new imperia order. First hed by the Spanish since the ate seventeenth century, then, except for Guam, passed to the Germans in 1899, the isands were taken by the Japanese during Word War I, an occupation ratified by the Treaty of Versaies. Even before they eft the League of Nations in 1935, the Japanese had begun fortifying the Marianas. By the 1940s the isands stood as a keystone in the defensive ine around the Japanese Empire. The Imperia Japanese Navy exercised theater contro over the Marianas and surrounding seas through its Centra Pacific Area Feet, commanded by Vice Adm. Chuichi Nagumo, eader of the Pear Harbor strike force. The Imperia Japanese Army controed a ground forces in the Marianas through its 31st Army, commanded by Lt. Gen. Hideyoshi Obata. Major subordinate commands were the 43d Division on Saipan and the 29th Division on Guam. Athough both units were understrength, having ost severa troop transports to American submarines, both were aso augmented by a number of independent battaions and nava anding units. Japanese forces in the Marianas, both Imperia Army and Navy, totaed about 59,000 men. The Marianas campaign expanded United States Army operations in a theater commanded by the U.S. Navy. Admira Nimitz assigned overa campaign responsibiity to Vice Adm. Raymond A. Spruance s Fifth Feet. Vice Adm. Richmond Key Turner woud command the Joint Expeditionary Force charged with the amphibious assaut. Turner himsef woud aso command directy a Northern Attack Force against Saipan and Tinian, whie a Southern Attack Force under Rear Adm. Richard L. Conoy woud assaut Guam. Vice Adm. Marc A. Mitscher s Fast Carrier Task Force and Vice Adm. Chares A. Lockwood s Submarine Force, Pacific Feet, woud cover a andings. Lt. Gen. Hoand M. Smith, USMC, Commanding Genera, V Amphibious Corps, woud contro the Marianas amphibious forces as each eft U.S. Navy contro at the water s edge. Three Marine Corps genera officers woud command the anding forces on the targeted isands: Hoand Smith on Saipan, Harry Schmidt on Tinian, and Roy S. Geiger on Guam. Amphibious units assigned to the Marianas incuded the 2d, 3d, and 4th Marine Divisions and a separate Marine brigade. Three major Army units the 27th and 77th Infantry Divisions and XXIV Corps Artiery were assigned from U.S. Army Forces in the Centra Pacific Area, commanded by Lt. Gen. Robert C. Richardson, Jr. Army and Marine Corps units totaed 106,000 men. Nava support for this huge force incuded 110 transport vesses and auxiiaries and 88 fire support ships, from rocket gunboats to aircraft carriers. 7

8 SAIPAN I TINIAN I AGUIJAN I ROTA I SOUTHERN MARIANAS 1944 APPROXIMATE CONTOUR INTERVAL 300 FEET 0 30 GUAM Mies Saipan The Marianas archipeago spans 500 mies from north to south. American panners chose their objectives from among the more heaviy fortified isands at the southern end of the chain Saipan, Tinian, Rota, and Guam. First targeted was Saipan, arge enough at fifteen mies ong by seven mies wide to aow combined arms maneuver. Inand hi masses dominated sandy beaches, with two prominent 8

9 Aeria view of Saipan, Juy (Nationa Archives) ridgeines framing a centra vaey panted in sugar cane. For invasion forces the major terrain features derived from the vocanic origin of the isand. Unike the ow and generay fat surface of cora isands, the terrain of Saipan presented a confusion of heaviy junged and jagged but ow ciff faces, rock outcroppings, sinkhoes, and caves often as difficut to see as to wak over and around. The highest peaks were the vocanic cones whose eruptions formed the isand: Mount Nafutan, 407 feet, to the southeast; Mount Kagman, about the same height, on the east coast; Mount Marpi, 833 feet, at the northern tip; and Mount Tapotchau, rising 1,554 feet on the west side of the centra vaey. A sma popuation, most of which the Japanese had enisted in sugar cane farming, resided in three west coast viages: Charan Kanoa, near the south end of the isand; Garapan at mid-coast; and Tanapag, six mies from Marpi Point. A prime subject of War Ministry reinforcement for more than a decade, Saipan was we fortified by Preassaut American aeria photographs identified 231 artiery pieces and 270 machine gun positions. The Japanese had one airfied Asito Fied in use in the south and another under construction at Marpi Point. Defending forces incuded over 25,000 Japanese Army troops and over 6,000 nava per- 9

10 U.S. reinforcements wade ashore from LSTs off Saipan. (Nationa Archives) sonne. Besides ampe artiery and modest aircraft support, these forces coud ca on an armored regiment of forty-eight tanks. Lt. Gen. Yoshitsugu Saito commanded both the 43d Division and the entire Saipan defense force. The sma size of Saipan dictated a straightforward pan of assaut. The 2d and 4th Marine Divisions woud and on the southwest coast and stake out a beachhead. Joined by eements of the 27th Division, the corps woud advance to the east coast, spitting enemy defenders into the northern haf and southeast corners of the isand. Army troops woud cear the atter, then join the two Marine divisions for the drive north to Marpi Point. Admira Spruance set the invasion date at 15 June. In the weeks before American troops crossed its beaches, Saipan was subjected to intense nava gunfire and air softening up. Beginning in February Admira Mitscher s fast carriers turned their air squadrons oose on Saipan and nearby isands in dayight raids; on 13 June they were joined by batteships and other surface ships firing continuousy on Saipan and Tinian unti D-day. Just before dawn on D-day surface ships aternated with bombers and fighters in saturating the anding beaches as troop-carrying anding craft approached the shore- 10

11 ine. Under this rain of hot meta and terror the Japanese coud do itte but cower in their bunkers; ony two artiery crews scored hits on U.S. Navy ships. A few sipped beer and sake as they recorded in diaries their awe of American firepower. At 0700 on 15 June the order Land the anding force! boomed through the compartments of thirty-four Landing Ship, Tanks, anchored three mies offshore. Bow doors swung open, ramps owered, and hundreds of amphibian tractors began crawing into the water. During the haf-hour run to the beach the growing amphibians were preceded by carefuy orchestrated barrages of arge-caiber nava gunfire, boat-mounted rockets, and carrier air strikes, first on the beaches and then, as the troops came across the sand, in the his beyond. Between 0843 and 0908 eight thousand marines anded on the west side of Saipan north and south of Charan Kanoa in the face of moderate opposition. They were brought ashore in 196 vehices of the Army s 708th, 715th, and 773d Amphibian Tractor Battaions and their Marine Corps counterparts. The anding force was escorted by 138 armored amphibian tractors, or amtracs, armed with 37-mm. or 75-mm. cannons which, it was hoped, woud enabe them to act as tanks ashore. By nightfa the marines had estabished a beachhead 10,000 yards wide and 1,000 yards deep. Heping to organize the beach were the first Army units ashore: the 311th and 539th Port Companies. That night the Japanese counterattacked at six points but were repused everywhere. The next day the first Army combat units came ashore: the 165th Infantry and the 105th, 106th, and 249th Fied Artiery Battaions. The marines shifted eft to make room for the 165th Infantry, whose mission was to sweep the southern shore of the isand and take Asito Fied. As the drive across the isand began, the corps front incuded from eft (north) to right the 2d Marine Division, the 4th Marine Division, and the 165th Infantry. As the 165th and the marines approached the airfied, enemy opposition stiffened. That night the enemy counterattacked with 1,000 troops and 38 tanks but was again repused. On the 17th the 165th Infantry mounted three assauts to overcome enemy machine gun, mortar, and artiery fire, as we as another counterattack, and reached the edge of the airfied. Behind the fighting, the 105th Infantry and 27th Division headquarters came ashore. The next day the 2d Battaion of the 165th Infantry, with four tanks and artiery support, waked across Asito Fied unopposed at That same morning the 27th Division became an independent command under Army Maj. Gen. Raph C. Smith. Whie Smith set up his 11

12 SAIPAN ISLAND 15 June 9 Juy 1944 Landing Beach Front Line, Date APPROXIMATE ELEVATION IN FEET and Above 0 4 Mies AFLD Marpi Pt. Mt. Marpi GARAPAN Fores Pt. Tanapag 2d Mar 27th Div HARAKIRI GULCH xx 4th Mar Hashigoru 2d Mar Div 15 Jun 4th Mar Div 15 Jun Aginan Pt. 2d Mar xx Charan Kanoa 20 Jun 4th Mar xx Asito AFLD Mt. Tapotchau 27th xx xx 4th Mar xx 24 Jun 27th Div Mt. Nafutan DEATH VALLEY Lauau Mt. Kagman MAGICIENNE BAY Cape Obiam 12

13 headquarters, the Japanese attempted a nove departure from doctrine: a counteramphibious anding that began with a sortie of sma boats southward toward the American beachhead from Tanapag Harbor eight mies upcoast. Surprised at the gift of easy targets, Navy gunboats and Marine artiery destroyed most of the enemy boats and drove the rest back to Tanapag. Resuming the offensive at noon, the 165th Infantry and the 4th Marine Division competed the move across the isand against feebe resistance. On 19 June Hoand Smith reoriented his corps to attack in two directions. His two Marine divisions and one regiment of the 27th Division formed a front across the isand in preparation for the advance north. The other two regiments of the 27th Division, the 105th and the 165th, began the mop-up of Nafutan Peninsua. Whie this redepoyment proceeded, the American ground effort was greaty assisted by a nava action 600 mies to the west. On June Admira Mitscher s fast carriers intercepted a arge enemy carrier task force. In a one-sided batte that became known as the Great Marianas Turkey Shoot, American piots and shipboard gunners shot down 385 of a tota of 545 panes aunched by the enemy and sank 1 carrier and 2 oiers. American submarines ater sank 2 more carriers. Another 17 enemy panes were destroyed on Guam anding strips. The U.S. Navy ost 26 panes and 54 men. The Batte of the Phiippine Sea so severey cripped the Imperia Japanese Navy that Japanese ground units in the Marianas woud have to fight on with no hope of resuppy. On Nafutan Peninsua the two Army regiments encountered unexpected resistance. With jagged terrain and poor coordination creating gaps in the American advance, the Japanese easiy stopped the troops with ony machine gun and mortar fire. Sugar cane obstructed visibiity and had to be burned, forcing more hats. Too often, sma terrain gains were given up when battaion commanders thought themseves in awkward positions at nightfa. With itte to show for two days of fighting by the Army troops, Hoand Smith began to ose patience. Anxious to start the advance north, he transferred the 165th Infantry and one battaion of the 105th to the centra front. To compensate, he sent six ight tanks to Nafutan. As Hoand Smith reoriented for his push north, Genera Saito redepoyed to bock the Americans. He paced his battered units some of which had suffered over 50 percent casuaties in a new defense ine anchored on Mount Tapotchau. Aready in a hopeess situation there was no onger any chance the Japanese woud see a friendy pane or ship Saito s troops sti had two sources of strength: idea defensive terrain and a wiingness to fight to the death. 13

14 Hoand Smith aunched his corps attack at 0600 on 22 June. The two Marine divisions advanced a mie and a haf against ight resistance and hated for the night. The next morning the 4th Marine Division shifted right to give the 27th Division a two-mie front in the center of the isand. As the 106th and 165th Infantry regiments moved forward to assigned sectors, their coumns crossed and tanged. The time required to unscrambe the units deayed the corps attack neary an hour. Under way ate in the morning, the offensive soon bogged down when Army battaions ran into the same combination of machine gun and mortar fire that was stopping their comrades to the south. In an effort to restore momentum, the corps commander transferred another Army battaion to the centra front, eaving ony the 2d Battaion, 105th Infantry, for the Nafutan mop-up. Soon more bad news came from Nafutan. Hoand Smith earned that athough the entire 105th Infantry was under corps tactica contro, the 27th Division commander, Raph Smith, was sti giving orders to the 2d Battaion of that regiment. Throughout 23 June, the 27th Division made itte progress north. On the right, the 165th Infantry dug in for the night ony some 700 yards ahead of its jump-off point. On the eft, the 106th Infantry had advanced just 100 yards. The fighting was focused on three areas: a sma cove in the mountain on the eft, named He s Pocket ; a ine of his on the right abeed Purpe Heart Ridge ; and the open expanse to the front dubbed Death Vaey. In Purpe Heart Ridge and other areas, the Japanese were using caves as deaying rather than as fighting positions. Rather than simpy fighting from the cave mouths, some enemy troops were remaining deep in the passages during dayight, then coming out to make night raids on American rear areas. On the night of the 23d, severa enemy tanks added to the 27th Division s frustration. One managed to penetrate the division s front and score a ucky hit on an ammunition dump. Exposions and fires drew more enemy fire, and the 106th Infantry had to withdraw in the darkness, canceing its sma but hard-fought gains of the day. The performance of Army regiments in centra Saipan greaty troubed Hoand Smith. The 27th Division had faen more than a mie behind the two Marine divisions on the fanks, and the entire corps advance woud have to stop unti the deep bend in the midde of the ine coud be straightened. No onger confident of the 27th Division s eadership, the corps commander took the drastic step of reieving Raph Smith, the division commander, on 24 June. Army Maj. Gen. Sanderford Jarman took over the division on an interim basis. 14

15 Mt. Tapotchau x d Mar Div xx INTO DEATH VALLEY June th Div xx Front Line, 24 Jun Japanese Resistance APPROXIMATE ELEVATION IN FEET and Above Yards He's Pocket DEATH ;y VALLEY Hi Abe Purpe Heart Ridge Lauau 4th Mar Div 15 The reief of an Army genera by a Marine Corps genera touched off one of the most unfortunate incidents of the entire Pacific war. The Smith versus Smith controversy, as it came to be known, threatened Army- Navy cooperation even more than had the Japanese attack on Pear Harbor. Hoand Smith fet justified in reieving his Army subordinate primariy because of the poor battefied performance of the Army division. Battaions of the 27th Division had dispayed, he beieved, insufficient aggressiveness both on the centra front and at Nafutan Point. They were repeatedy ate in beginning attacks, easiy pinned down, and quick to withdraw, whie at the same time Marine units were gaining more ground athough at higher cost in casuaties. The corps commander saw no aternative to repacing the division commander, but the action soured interservice reations in a theater where smooth coordination was essentia. Resuming the two-front advance on 25 June, Generas Hoand Smith and Jarman tried new tactics to end the staemate. On the Nafutan front the 2d Battaion, 105th Infantry, was assisted by 40-mm. and 90-mm. antiaircraft guns pacing direct trajectory fire on Japanese positions, enabing famethrower crews to reach into caves. On the centra front Army battaions no onger tried to advance in a inear fashion, keeping contact with Marine units on their fanks, but instead moved diagonay across Death Vaey to attack He s Pocket and Purpe Heart Ridge from severa directions. If the enemy staed headon assauts, the Americans woud try singe and doube enveopments. Best of a for troops in the vaey, an effective method of cearing caves was evoved. Whie artiery barrages occupied enemy gunners, Hashigoru

16 27th Division troops advance behind tanks on Saipan. (Nationa Archives) tanks and 40-mm. gun mount crews dashed in front of enemy positions to fire point-bank into cave mouths, with famethrower teams competing the attack by firing jeied gasoine into openings. On the 27th good news came from both fronts. In the morning the 2d Battaion, 105th Infantry, overcame the ast enemy strongpoint on Nafutan Peninsua. In Death Vaey the 1st Battaion, 106th Infantry, ceared most of He s Pocket, whie the other two battaions of the 106th and the 2d Battaion, 165th Infantry, secured a but the ast rise on Purpe Heart Ridge, Hi Abe. The next day Maj. Gen. George W. Griner took command of the 27th Division and soon coud report a victory to Hoand Smith when the 1st Battaion, 106th Infantry, kied the ast enemy sodier in He s Pocket. Buiding momentum, Griner s men shrugged off an enemy attack on the 106th Infantry but had to hat when the 3d Battaion, 105th Infantry, was hit by friendy artiery. Finay, on the 30th, the 2d Battaion, 165th Infantry, topped Hi Abe, and the 27th Division earned praise from Hoand Smith for cearing He s Pocket, Death Vaey, and Purpe Heart Ridge. 16

17 Now ony a six-mie sweep to Marpi Point remained. Against feebe opposition the 3,000 or so remaining Japanese had no artiery or armor and itte water the Americans moved ahead rapidy. The narrowing of the isand reduced the corps front to two divisions, the 27th on the eft shore, the 4th Marine on the right. Army troops found the next Japanese ine in a ravine just beyond Tanapag viage. Repeated attacks by two battaions and severa tanks over two days finay wore down the enemy. After seeing wounded Japanese shoot comrades and expode grenades against themseves, American troops named the cut Suicide Guch. Moving beyond Tanapag, Griner s men found fortified ciffs and caves abutting the beach. But in the hard schoo of Death Vaey, Army troops had mastered tank-infantry coordination, and they ceaned out the ciffs in one day. His troops backed against the sea, Genera Saito ordered one more assaut by a sti abe to wak, then he iteray fe on his sword. In the predawn darkness of 7 Juy, severa thousand enemy sodiers unged into the 1st and 2d Battaions of the 105th Infantry. Here the Japanese earned the Americans coud be just as tenacious in the defense as they had been on Purpe Heart Ridge. At the approach of the enemy Lt. Co. Wiiam J. O Brien raied his men by running aong his perimeter firing pistos at the attackers. When his ammunition ran out, he continued with a machine gun unti he was kied. Esewhere on the ine, Sgt. Thomas A. Baker was severey wounded in the enemy onsaught. Refusing evacuation, he demanded ony a oaded pisto. When his comrades returned they found eight Japanese bodies around his own. For their extraordinary demonstrations of heroism, O Brien and Baker were posthumousy awarded the Meda of Honor. For his counterattack, Griner sent in the 106th Infantry with tanks. In another day-ong batte the Americans regained ost terrain and in the process neary annihiated the enemy. Two days of itte more than cave demoition brought the 165th Infantry and Marine Corps units to Marpi Point, ending the batte for Saipan. In the cosing scene of their futie defense, the Japanese gave another gruesome demonstration of fanaticism. Driven to the beaches, dozens of enemy survivors swam to reefs rather than accept food and medica care, then committed suicide before increduous Americans. The strugge for Saipan cost the Army 3,674 kied, wounded, and missing, whie Marine casuaties totaed 10,437. When Admira Turner decared the isand secure on 9 Juy, the Army had more experienced units, and the men of the 27th Division had earned how to overcome some of the toughest Japanese defenses in the Pacific. 17

18 2d Mar Div 4th Mar Div 24 Ju Ushi Pt. Afds Asiga Pt. 26 Ju MT. LASSO ASIGA BAY Gurguan Pt. Afd 2d Mar xx 4th Mar Masaog Pt. Tinian Town TINIAN ISLAND SUNHARON BAY 24 Juy 1 August 1944 Marpo Pt. Landing Site Front Line, Date APPROXIMATE ELEVATION IN FEET Lao Pt and Above Yards Tinian Ony 3.5 mies to the south and two-thirds the size of Saipan, Tinian presents a and surface markedy different from its neighboring isand. Despite its vocanic origin, Tinian is unusuay fat, with Mount Lasso the highest peak at 564 feet. Few natura obstaces exist. The Japanese had aready buit three airfieds and easiy controed the sma native popuation, which ived in sugar cane settements and Tinian Town. Ony the act of anding itsef woud be a probem, since about 90 percent of the coastine is ciff face. The pan for Tinian caed for a two-division amphibious assaut. The 2d and 4th Marine Divisions woud move by boat from Saipan to beaches on the northwest coast of Tinian, then sweep down the twevemie ength of the isand. Inteigence reports put the defending force at about 8,000 men with a dozen tanks and ony a few coasta batter- 18

19 ies. For this phase of the Western Pacific Campaign a cear distinction of missions by service prevaied. The marines were given a infantry missions, whie Army units were to provide artiery and engineer support. The marines woud bring ashore ony ight artiery 75-mm. pack howitzers. Brig. Gen. Arthur M. Harper s XXIV Corps Artiery woud contribute heavier support from thirteen battaions of 105-mm. and 155-mm. pieces, in a 156 guns initiay firing from Saipan. Anxious to continue the momentum of their victory on Saipan, Admira Turner and Lt. Gen. Hoand Smith quicky turned their attention to Tinian. Ony five days after the invasion of Saipan, Battery B, 531st Fied Artiery Battaion, had begun firing its 155-mm. guns at Tinian. On 8 Juy three more Army artiery battaions reoriented southward, and by the time fighting on Saipan ended XXIV Corps Artiery woud have fired 331 missions over 7,500 rounds at Tinian from Saipan. On the morning of 24 Juy the two Marine divisions anded under the command of Lt. Gen. Harry F. Schmidt, USMC. Of the 415 amphibious vehices used to bring the troops ashore, 225 came from the Army s 534th, 715th, and 773d Amphibian Tractor Battaions. The Army s 708th Amphibian Tank Battaion stood by offshore, ready to and and support the infantry. As the marines pushed beyond the shoreine, the Army s 1341st Engineer Battaion administered the beach, sending personne and suppies inand and transferring casuaties to ships. Overcoming ight opposition, the marines estabished a beachhead two mies wide and a mie deep by nightfa. As on Saipan, the Japanese tried to push the Americans back into the sea their first night ashore, but once again the enemy faied, osing 1,241 men in the attempt. Thereafter the roing terrain aowed a rapid infantry-armor advance, eaving the Japanese defenders itte time to reorganize their crumbing defenses. On the 26th the marines captured their first airfied and ceared Mount Lasso, but the gaoping advance was finay sowed by the weather. On 29 Juy the tai of a typhoon ashed across the isand, destroying two ponton causeways used to receive shipborne units and suppies from Saipan, preventing two batteries of the Army s 106th Fied Artiery Battaion from reaching Tinian. However, the third battery of the 106th and a of the 419th Fied Artiery Group had aready arrived. The night of 31 Juy, as the marines cosed on the southern tip of the isand, enemy survivors gathered for a ast-gasp counterattack. Led by a regimenta commander, the Japanese rushed the Marine ine three times in the darkness but faied to break through. Dayight reveaed 19

20 over one hundred enemy dead, and on the evening of 1 August Genera Schmidt decared the isand secure. Whie airfied improvement progressed, the troops carried out a difficut mop-up operation which by year s end had accounted for 542 more Japanese sodiers on the isand. The nine-day batte for Tinian cost the attackers 328 kied and 1,571 wounded. For this high price, Marine Corps infantry and Army artiery had gained one of the best isand air bases in a the Pacific. From Tinian ong-range American bombers woud soon bring the war to the enemy s home isands, ending a hopes of Japanese resurgence. Guam Thirty-four mies ong and between five and nine mies wide, Guam is the argest isand in the Marianas. It has a hiy surface with shoreine ciffs, many caves, and abrupt rises and draws. The isand s position 105 mies south of Tinian gives it a more tropica cimate, which for ground troops meant thicker vegetation to cut through. Unike the rest of the Marianas, Guam had been under American jurisdiction from 1898 unti the Japanese invasion of 10 December 1941, a history that ent to the isand s iberation the same mora imperative as that attached to the Phiippines. American eaders beieved that the civiian popuation was sti oya to the United States and was at heart not freey cooperating with the Japanese occupiers. The American invasion of Saipan froze the defensive deveopment of Guam in an eary stage. In mid-june 1944 the Japanese garrison was ony about haf the size of that on Saipan, with fewer artiery pieces and tanks to defend an isand more than twice as arge as the atter. Nevertheess, the 18,500 defending troops represented a considerabe force. Of primary interest to the Americans was an airfied on Orote Peninsua, a rocky finger off the west coast. Lt. Gen. Takeshi Takashima commanded the garrison through his 29th Division staff, under the genera supervision of the theater commander, Lt. Gen. Hideyoshi Obata. The American invasion of the Marianas had caught Obata on Guam, and there he woud stay throughout the campaign. Admira Spruance set the invasion date for 21 Juy Southern Troops and Landing Force panned to take Guam with a joint mutidivision force. After the 3d Marine Division and 1st Provisiona Marine Brigade staked out a beachhead, the 77th Infantry Division woud and and operate in its own sector. Once ashore, these units woud come under command of Lt. Gen. Roy S. Geiger, USMC. Their first objective was Orote Peninsua; combat units woud then push across the isand, cear the southern end, and reorient for a sweep to the north coast. 20

21 Japanese defenders on Guam received the heaviest softening-up gunfire and bombing the U.S. Navy had yet produced in the war. Beginning in March 1944, carrier task forces struck enemy bases on nearby isands, especiay Truk and Woeai in the Caroines. During the two weeks before the invasion the Navy orchestrated day and night concentrations of surface gunfire from six batteships, nine cruisers, a dozen destroyers, and many rocket-aunching gunboats as we as numerous strafing and bombing sorties from Army B 24s and Navy carrier-based squadrons. This preparation destroyed a nava gun positions visibe from the air and about haf the arge guns in caves. On the morning of 21 Juy Marine units came ashore on both sides of Orote Peninsua. The 3d Marine Division anded on the north beach near the town of Agana, whie the 1st Provisiona Marine Brigade assauted the south beach near Agat. Opposition was surprisingy heavy after weeks of preparatory fire, and twenty-two amtracs were sunk. But the marines kept coming and by nightfa had pushed about a mie inand at both points. Maj. Gen. Andrew D. Bruce s 77th Infantry Division began anding the afternoon of D-day. But even before Army troops hit the beach they had to contend with a probem the marines had not faced. Because the 77th was in corps reserve, the division had no amtracs aotted; when anding craft reached the reef ine, troops had to debark and wade severa hundred yards to the beach. Tanks and trucks had to be towed by budozers, and some were ost in the surf. Most of the 305th Infantry was ashore by 2130, in time to hep turn back the expected enemy counterattack. In its first combat on Guam, the 305th ost 7 dead and 10 wounded whie, with the marines, kiing 268 enemy. The next morning the regiment took a sector on the 1st Provisiona Marine Brigade eft and jumped off on its first mission: cearing a road inand of Agat. By the afternoon of 22 Juy the 77th Division had a of its fied artiery ashore: the 304th, 305th, and 902d Battaions. Over the next two days the 306th and 307th Infantry regiments and Genera Bruce s headquarters waded in from the reef ine, whie troops ashore continued expanding the beachhead. On 24 Juy the 77th Division took over the southern perimeter; two days ater the 1st Provisiona Brigade began cearing Orote Peninsua, an operation requiring five days. But before the attack on Orote coud begin in earnest, Genera Takashima aunched a major counterattack against Marine ines the night of Juy. His troops attacked one point on the ine seven times but were repeatedy repused. Esewhere they penetrated deepy enough that cooks and hospita patients had to take up rifes and bayo- 21

22 ISLAND O 21 Juy 10 A Ritidian Pt. 7 Aug 6 Aug Orote Peninsua 77th Div 21 Ju Afternoon 1st Prov Mar Bde 21 Ju Morning AFLD 25 Ju Sumay Agat 29 Ju Mar Bde xx 77th Mt. Lamam Piti 3d Mar Div 21 Ju 3d Mar xx 77th Maanot Pass 25 Ju 29 Ju AGANA 3d Mar xx 77th 3 Aug AFLD 31 Ju 3d Mar xx 77th 1 Aug Mt. Barrigada 3 Aug Yigo 6 Aug Meriza APPROXIMATE EL Mi

23 7 Aug 3d Mar xx 77th Mt. Santa Rosa F GUAM ugust 1944 Landing Site Front Line, Date EVATION IN FEET Pati Pt and Above 4 es nets. When it was over, the American beachhead remained intact, neary 3,500 enemy ay dead, and the Japanese situation on Guam was hopeess. With Orote airfied under his contro, Genera Geiger turned his attention farther inand. His troops now faced a mountainous expanse to the south and over two-thirds of the isand to the north. Not knowing where the enemy woud attempt a fina defense, Geiger accepted Bruce s proposa to aunch imited probes into the southern his. For six days the 77th Reconnaissance Troop conducted patros with Chamorro guides but found no enemy. His southern fank secure, Geiger reoriented to the north. Meanwhie, on Juy the Japanese had again tried to puncture the American beachhead perimeter, a faied endeavor in which they ost Genera Takashima to a machine gun burst. Genera Obata took over and franticay pued his depeted force north to buid a new defensive ine. His troops were short of ammunition and rations and had ony about a dozen tanks eft. A few ight artiery pieces remained, but the men were fast osing the strength to musce them up and down his. Obata tried to anchor his interna defenses on Mount Barrigada, five mies east of Agana, but American tanks punched through before his units dug in. However, as the Americans moved north, they now found the terrain and cimate more formidabe. Thickening rain forest opened gaps between units and ruined aignment, and heavy rains and accompanying mud added to the ensuing communications and ogistica confusion. These conditions brought the 77th Division to the awkward position of hoding ony the eastern haf of Mount Barrigada at nightfa on 3 August. Bruce s infantry took the rest of Mount Barrigada the next day, but a major breakdown in Army-Marine iaison marred the achievement. After basting through two Japanese roadbocks, tanks and troops of the 307th Infantry came upon what ooked ike a third enemy position. The tankers opened fire and saw, instead of Japanese taking cover, Americans franticay waving hemets. When the tanks ceased fire, seven marines ay wounded. During the next three days Japanese resistance decined to the nuisance eve, and ony the thick vegetation and mud prevented a high-speed dash to the northern beaches. Here 23

24 and there isoated enemy detachments threw themseves against Bruce s troops and the marines advancing up the isand, sti causing considerabe casuaties. On the night of 5 6 August, for exampe, an enemy patoon and two tanks hit the 305th Infantry, kiing fifteen and wounding forty-six. By nightfa on the 6th Obata s ast defensive ine had coapsed. The next day the Japanese put together their ast organized resistance, a roadbock with two tanks that kept the 307th Infantry out of the viage of Yigo ony a few hours. On the 8th the same regiment foowed a nava bombardment to take the northernmost height, Mount Santa Rosa. The fight for Guam ended with the worst kind of battefied accident: Americans firing on Americans. At noon on 8 August the 306th Infantry received and returned fire for two hours before discovering the source: a Marine unit on the division s eft fank. Six hours ater two 77th Division battaions exchanged fire but reaized their error within a few minutes. Investigations reveaed these firefights and the earier 4 August incident resuted from misunderstood signas and sector boundaries. These tragic mishaps added neary 20 casuaties to the campaign tota of 7,800, of whom 2,124 died in action or of wounds. The 77th Division ost 839 kied in action. On 10 August Genera Geiger decared resistance on Guam ended and the same day received Admiras Nimitz and Spruance for a tour of the batte-scarred isand. The Paaus Victory in the Marianas brought United States Army and Navy forces cose to their next major objectives in the Pacific: the Phiippines and the Japanese home isands. American forces were now in a position to interdict directy Japan s vita East Indies oi fieds as we as to strike targets in the Phiippines and Japan. Capture of the Paau Isands woud aow more effective prosecution of both goas. Nine hundred mies southwest of Guam, the Paaus were the ast enemy-hed isands between American forces and the Phiippines. Of the eighty-mie-ong chain, the argest isands and argest enemy garrisons were in the northern Paaus, but weaker defenses and the potentia for airfied construction drew the attention of Genera Geiger s III Amphibious Corps to the isands of Peeiu and Angaur in the south. Vocanic in origin, each isand presented a ow profie and rough surface of ciff faces, sinkhoes, cora outcroppings, caves, and thick vegetation. Ony seven mies ong, Peeiu had an airfied in the south; a swamp covered most of the eastern side. Tiny Angaur, ony three mies ong, ay just six mies away. A sma popuation farmed and fished on both isands and, on Angaur, worked a phosphate pant. The 24

25 Cape Pkuangeu ;; yy ;; yy ;; Lake Saome 20 Sep Lake Aztec 81st Div (-) 17 Sep Cape Ngatpoku Cape Ngariois Phosphate Pant SAIPAN Cape Ngaramude ;; 19 Sep 19 Sep 20 Sep ;; yy Rocky Pt. 81st Div (-) 17 Sep ASSAULT ON ANGAUR September 1944 Front Line, 18 Sep Axis of Advance, Date Japanese Resistance APPROXIMATE ELEVATION IN FEET and Above Yards Japanese hed the Paaus with 49,000 men under Paau Sector Group and 14th Division commander Lt. Gen. Sadao Inoue, who depoyed 10,500 troops on Peeiu but ony 1,400 on Angaur. To take the two isands, American panners seected the Army s 81st Infantry Division and the 1st Marine Division. On the morning of 15 September, after heavy Navy surface and air preparatory fires, the 1st Marine Division came ashore on the southwest beaches of Peeiu. The marines met strong opposition but by nightfa hed a beachhead neary two mies ong and a mie deep. As esewhere, however, the Japanese defenders showed no signs of giving up. Athough the marines advanced steadiy and took the airfied, casuaty rates after five days exceeded 50 percent in some units. By 20 September the marines were exhausted, and a staemate had resuted. 25

26 On Angaur Maj. Gen. Pau J. Mueer ed the 81st Division into combat for the first time on 17 September. After a six-day Navy preparation, the 321st Infantry assauted the southeast coast, the 322d Infantry attacked the northeast shore, and the 323d Infantry stood offshore in corps reserve. Initiay mines and congestion on the cratered, shrapne-ittered beaches sowed the anding, but the 52d, 154th, and 306th Engineers soon ceared and organized passabe avenues inand. Spearheaded by the 710th Tank Battaion and supported by the 316th, 317th, 318th, and 906th Fied Artiery Battaions, the two infantry regiments once ashore made rapid progress against sporadic opposition. By 20 September Mueer s men had spit the defenders and chased most of the remaining Japanese back toward the western beaches of the tiny isand. Meanwhie, on Peeiu the 1st Marine Division commander, Maj. Gen. Wiiam H. Rupertus, wrested with a diemma. Mindfu of the wrenching Saipan controversy, he preferred that Peeiu remain an a-marine operation. But when casuaties continued to mount, he had to accept reinforcement. On 22 September the 321st Infantry transferred to Peeiu with the mission of cearing a mie-ong stretch of beach and junge-covered his. The next day the U.S. Army unit moved inand, preceded by artiery and nava gunfire pounding the his, whie a Marine regiment eapfrogged upcoast to cear the northern tip of the isand. On the 24th, Army troops found a path into the his and named it 321st Infantry Trai. Mueer s men used the trai to spit the enemy, one pocket to the south around Umurbrogo Mountain, the other north. Both woud prove difficut to reduce, the former because of rough terrain, the atter because, to the shock of the Americans, Genera Inoue had managed to bring 500 fresh troops to Peeiu from the northern Paaus. On Angaur the 81st Division aso faced two pockets of resistance. A sma number of enemy were trapped on a strip of dry ground between the southeast beach and a swamp, effectivey out of the fight. But the argest number of remaining enemy defenders coaesced on the Bow, a hi mass around Lake Saome in the northwest. Even whie esewhere on the isand the 1884th and 1887th Engineer Aviation Battaions began airfied construction, the enemy made a ast stand. On 20 September the 322d Infantry and attached tanks moved against the Bow. Rai ines serving the phosphate pant offered easy avenues into the area, but Japanese mines and artiery made their use dangerous. Inside, some 750 enemy manned artiery and antitank weapons, mortars, and machine guns, determined to fight unti the end. 26

27 ASSAULT ON PELELIU 15 September 15 October 1944 Front Line, Date Axis of Advance, Date Japanese Resistance APPROXIMATE ELEVATION IN FEET and Above Yards Kongauru I Ngesebus I Afd ; 30 Sep Amianga Mt. Murphy I 1st Mar Div 15 Sep 323d Inf 15 Oct 321st Inf 23 Sep ; ; ; ;; ; y ;; yy 20 Sep Afd Umurbrogo Mt. 16 Sep 19 Sep 18 Sep Kamiianu Mt. 19 Sep 23 Sep 21 Sep 22 Sep 16 Sep Over the next five days the 322d repeatedy attacked the Bow. The 2d Battaion broke through the southern rim on the 23d but was quicky forced out. Three days ater the regiment tried an attack from the north with more success. After heavy artiery had ceared the way, tanks and troops punched through the rim and expanded a foothod, then turned away a weak enemy thrust that night. Attacks resumed the next morning on three sides of the Bow. More troops entered the gap in the north and began dispersing enemy weakened by hunger and thirst. Inside the Bow, Mueer s troops found a way to dea with the dreaded enemy cave positions so numerous on vocanic isands. Rather than spend days basting them with artiery, gun mounts, and 27

28 famethrowers, the troops used budozers to sea the entrances. By dusk on the 29th the foor of the Bow had been ceared, and ony a aborious mop-up of the northern rim remained. Meanwhie on Peeiu the marines had encountered unexpected opposition at the northern tip of the isand. On 27 September the 321st Infantry moved north with tanks and famethrowers to assist and then reieve the marines. After six days of ceaning out caves and draws, the 321st chased the Japanese off the ast rise, and on the 30th Geiger decared both Peeiu and Angaur captured. Athough American nava and air units had fu access to Peeiu, Japanese troops sti hed the Umurbrogo Pocket. Marine infantry, armor, and artiery units hammered the pocket unti 15 October, when Army units took over. The 321st Infantry moved against the northern and eastern sides of the pocket, whie Genera Geiger sent his sti fresh reserve regiment, the 323d Infantry, to the southern and western sides. Now 81st Division troops began a grueing yard-by-yard fight for the maze of jagged his and steep cuts. Wiing to try anything against the Umurbrogo Pocket, Mueer s men hit upon two effective innovations: air-deivered napam and famethrowers mounted on tracked anding vehices. As reduction of the pocket continued, 81st Division troops found themseves being fired upon from points just secured. In retaking such positions, the Americans discovered the Japanese had buit tunnes to connect severa caves. Attempting to counter these underground compexes, the troops poured oi into crevices and ignited it with phosphorus grenades. Above ground they took care to fortify with sandbags a terrain gains, no matter how sma. During the ast week of October the 323d Infantry took over reduction of the pocket. The fina American victory was deayed by a typhoon the first week in November, but the end was brought coser when 81st Division troops took the ast fresh water source of the Japanese. Finay, on 27 November, the 323d Infantry competed cearing the troubesome pocket and decared Peeiu secure. The strugge for Peeiu and Angaur had put Army units into some of the most difficut fighting of the entire war for territory of comparabe size. Two and one-haf months of fighting on the tiny isands cost the Army 542 kied and 2,736 wounded. Anaysis Victory in the Western Pacific Campaign made the continued American advance across the Pacific certain. Japan s southern fank 28

29 Genera Mueer wecomes Admira Hasey to Angaur after the occupation. (Nationa Archives) now ay wide open, and after the Batte of the Phiippine Sea the Japanese no onger had the nava air strength to counter American aircraft carrier task forces. United States Army Air Forces and Navy task forces had won the bases that woud aow them to sever Japan s ink to the East Indies oi fieds, interdict its suppy ines to China, and attack the Japanese home isands themseves. Furthermore, no enemyhed territory remained between American forces and the Phiippines. But these gains had not come easiy. In the Marianas and Paaus the Army ost 7,791 dead and wounded, the Marine Corps and Navy over 26,000 dead and wounded. Japanese casuaties totaed more than 72,000, a but a few hundred kied. The obvious advantage of the air bases and anchorages gained on Saipan, Tinian, and Guam justified the Marianas invasion, but the minor strategic vaue of the Paaus eft troubing questions about overa American decision making in the Pacific. Intended to support subsequent operations against the Phiippines, the airfieds and ports of Peeiu and Angaur utimatey proved ess than essentia. When construction on those isands fe behind schedue, Army air squadrons used aternate sites without adversey affecting operations to the north. Uithi Ato in the Caroines, occupied in an unopposed anding by the 323d Regiment of 29

30 the 81st Division in September 1944, proved of greater vaue than the Paaus for Pacific Feet operations in the Phiippines and Okinawa. Beyond debate, however, is the vaue of experience gained by Army and Navy staffs and the three Army divisions invoved in the Western Pacific Campaign. Marred by the Saipan controversy and tactica confusion over Army and Marine sector boundaries esewhere, the Western Pacific Campaign hardy seems an exampe of successfu interservice rea- 30

31 Tanapag Harbor, Saipan, Pacific, by Hans Mangesdorf. (Army Art Coection) tions. But those few incidents shoud not obscure the cooperative panning for dozens of amphibious operations and the hundreds of instances of successfu Army Navy Marine Corps coordination of nava gunfire, artiery, air support, and suppy that occurred routiney throughout these campaigns. Proof that Smith versus Smith did not mortay wound Army-Navy reations in the Pacific came on Peeiu, when the 81st Division regiments first assisted and then took over reduction of the Umurbrogo Pocket from the 1st Marine Division. 31

32 In some respects inteigence was a success, in others a faiure. Since American aircraft enjoyed amost unopposed access to the targeted isands, aeria photographs coud be examined eisurey and updated continuousy. But these photos, as we as Navy reconnaissance of beaches, often reveaed ony arger enemy positions and not the weter of tiny but in the end deadier infantry positions. As a resut, the Americans approached each isand with an unreaistic idea of how ong a campaign to pan. Predictions about three operations in the Western Pacific Campaign were spectacuary off the mark. On Saipan, Hoand Smith s staff beieved Nafutan Peninsua was hed by ony about 300 straggers, but the 105th Infantry had to ki 1,050 enemy there before the peninsua coud be secured. Genera Mueer decared Angaur secure on the fifth day of fighting, but the batte continued thirty-one days onger. And Genera Rupertus expected a four-day fight for Peeiu, but decisive contro of the isand took sixteen days to estabish, and the ast enemy troops hed out for two and one-haf months. Army units earned much about amphibious operations in the Marianas and Paaus, but a costy probem occurred whie bringing them ashore on Guam. Faiure to aot anding craft to the 77th Division resuted in much time wasted and equipment ost. Many bady needed vehices never reached the beach, having faen into cora gaps or craters basted by nava preparatory fires. This probem made cear the need for better scheduing of anding craft at joint panning sessions. Each of the three Army divisions invoved in the Marianas and Paaus operated with a components in the fied for the first time. One regiment and part of another from the 27th Division had seen brief combat before commitment to the Marianas. The 165th Infantry had taken Makin Ato in the Giberts in November 1943, and two battaions of the 106th Infantry had assisted in the capture of Eniwetok in the Marshas in February Command and staff experience at the division eve was initiay minima. As each division anded on its assigned isand, troops and officers had to earn by painfu experience the teamwork required to achieve their objectives. Each division showed obvious improvement in its own operations, but when the entire campaign was viewed from beginning to end, it appeared that some troops were making the same mistakes repeatedy. Often high casuaties had simpy prevented tactica essons from being absorbed by the eadership of smaer units. One obvious exampe was the response of new infantrymen to enemy fire. Companies and battaions were too easiy pinned down by ight opposition, sometimes ony rife fire. Ony experienced infantrymen coud rapidy distinguish between sporadic opposition and that 32

33 necessitating artiery and air strikes. Another exampe was defensive positioning. Too often battaion commanders withdrew their units from hard-won terrain at the onset of darkness if their position appeared awkward and difficut to defend. Refecting a rigid textbook approach to tactics, such procedures were ony graduay adjusted by better knowedge of the enemy and better use of weapons and equipment, incuding items as simpe as sandbags. Yet despite the continuing introduction of new units, rea progress occurred. By the time the 77th and 81st Divisions entered combat they had much more information about the enemy and more weapons to use against him than the 27th Division had had at the beginning of the campaign. Fire support avaiabe to Army divisions in the Western Pacific overcame Japanese batteries with itte difficuty, but probems with other targets, as we as with coordination, persisted. The three major sources of fire support artiery, nava gunfire, and aircraft were ony partiay effective against enemy personne, usuay because of thick vegetation and rocky terrain, and none coud touch caves and tunne compexes. The pan to use armed and armored amphibian vehices ashore as tanks had to be set aside, since the amtracs were needed more for the ship-to-shore ferrying of suppies. Methods for requesting and adjusting fire remained controversia. Ground commanders down to battaion eve wanted authority to ca directy for nava and air support, but the Navy answered requests from division commanders ony. As a resut, ground troops normay had to wait at east haf an hour for an air strike even if the panes were aready overhead and severa hours if on the ground. Within the Army divisions, infantry-armor coordination remained inadequate. Troops coud not tak to tank crews without opening a hatch. And too often map-or terrain-reading errors brought American fire within American ines. Encouraging for future operations, the three Army divisions showed the abiity to innovate in response to terrain and enemy. On Saipan the 27th Division eary demonstrated ski in infantry-armorartiery coordination. But when enemy defenses in Death Vaey proved resistant to prevaiing doctrine on combined arms assauts, officers and men on the scene made an adjustment in the form of firepower mobiity: 40-mm. gun mounts to reach into caves. Napam, first used on Tinian, rendered cave tactics more precarious. On Guam and the Paaus, the 77th and 81st Divisions further refined combined arms tactics by adding famethrowers and oi and by caing for Navy aircraft and anding vehices to deiver these weapons more effectivey. Innovation continued with the use of budozers to 33

34 sea caves and sandbags to hod terrain. Rifemen experimented further with sandbags, pushing them ahead as they crawed over difficut terrain on Peeiu. Innovation aso marked the combat support effort. In the Marianas, Army and Navy officers discovered that DUKW anding craft, unarmed amphibious trucks, were just as vauabe in ferrying suppies between ships and the front ine as in bringing assaut troops ashore because they coud drive through the usuay disorganized beach without unoading. Whie DUKW companies supported combat farther inand, other units addressed the cutter on the beach. Engineer units fied the many craters from nava gunfire preparation and then acted as shore party personne to manage suppy dumps. A few innovations proved hasty. The practice of seaing caves with budozers eft the possibiity that trapped enemy woud ater emerge from undiscovered openings to harass Americans from the rear. To ensure security, infantry or engineer units had to reopen and patro caves, a time-consuming process. A response to the unusuay thick vegetation on Guam and Peeiu regiments moving in coumn without fank security aso had to be reconsidered. When a ead unit overcame an enemy strongpoint and moved on, the foowing unit often discovered that enemy survivors had reoccupied the position, which had to be taken again. In the Western Pacific the United States Army won important victories, and in the process gained three batte-tested divisions. In the coming months veterans of the 27th, 77th, and 81st Infantry Divisions woud find their hard-earned experience invauabe in the Phiippines and on Okinawa. 34

35

36 Further Readings The officia history of the Western Pacific Campaign has been augmented in recent years by a number of popuar accounts. The Smith versus Smith eruption during operations on Saipan is treated in detai by Harry A. Gaiey in his Howin Mad vs. the Army: Confict in Command, Saipan 1944 (1986). The same author examines the most difficut operation in the Paaus in his Peeiu 1944 (1983), which considers Angaur ony briefy but incudes anecdotes from a ranks and both sides. Joint operations on both Peeiu and Angaur are covered by Staney Fak in Boodiest Victory: Paaus (1974). The most extensive treatment of operations in the Marianas and Paaus remains, on the former, Phiip A. Crow, Campaign in the Marianas (1960) and, on the atter, Robert Ross Smith, The Approach to the Phiippines (1953), chapters 19 and 21 24, both voumes in the series United States Army in Word War II. CMH Pub Cover: Troops of the 305th Infantry, 77th Division, on Guam. (Nationa Archives) PIN :