The Campaign Begins
The Plans and the Forces
American Plans of Attack
The Luzon Campaign had been under way less than a month when General MacArthur decided that the time had come to put into effect his plans for securing the bypassed islands of the Southern Philippines.1 For a variety of reasons the theater commander regarded speed essential for the move into the southern islands, although he knew operations there would divert forces from Luzon and delay its reconquest. However, obvious disadvantages and dangers faced the Filipinos on the bypassed islands, garrisoned as they were by Japanese troops who had no hope of succor and whose tempers and morals could hardly be expected to improve as they came to realize that Japan's defeat was inevitable. To leave the Filipinos of the southern islands unnecessarily exposed to evident dangers for an unduly protracted period could tend only toward undermining the prestige--seriously damaged by the loss of the Philippines in 1942--that the United States had regained in the Far East with the landings on Leyte, Samar, Mindoro, and Luzon.
Plans for the strategic conduct of the war also demanded an early move into the Southern Philippines. The Allied Air Forces was responsible, within the limits of its capabilities, for helping to sever the Japanese lines of communication through the South China Sea. This responsibility made it imperative to capture airfields as soon as possible from which the Allied Air Forces could project land-based air strength over the waters west of the Philippines more effectively than it could from the Clark Field center on Luzon or from southwestern Mindoro. The attention of Southwest Pacific planners was, accordingly, drawn toward Palawan, westernmost large island of the Philippine archipelago. Airfield sites on Palawan were 250 miles southwest of the Mindoro airstrips, 400 miles south-southwest
of Clark Field, and around 150 miles farther west than either.
MacArthur's plans furthermore called for the ultimate reoccupation of the East Indies in a campaign that would start with the seizure of Japanese-held oil resources in northern Borneo as soon as land-based air support became available. Except for the projected air base on Palawan, the Allies had no fields within medium bomber or fighter range of northern Borneo, and even Palawan was not satisfactory as a fighter base. Therefore, Southwest Pacific planners decided to secure airfields on the southern tip of the Zamboanga Peninsula of southwestern Mindanao, and along the Sulu Archipelago, which stretches southwest from Zamboanga almost to the coast of Borneo. (See map, p. 20.)
Weather also played a part in the decision to launch early attacks into the Southern Philippines. Planners knew how important it was to have the campaigns in the southern islands well under way before the summer rains began, and they recognized the importance of having airfield construction in hand before wet weather created engineering problems like those that so delayed air base developments on Leyte in late 1944.
Motivated not only by a sense of strategic urgency but also by his well-publicized personal desire to liberate all the Philippines quickly, General MacArthur waited only to be certain that Sixth Army could secure the vital objective area on Luzon--the Central Plains-Manila Bay Region--within a reasonable time before he directed the Allied Air Forces, the Allied Naval Forces, and the U.S. Eighth Army to launch the campaign in the southern islands. Accordingly, on 6 February 1945, after Sixth Army troops had been in Manila but three days, MacArthur ordered the seizure of Palawan. A week later he issued additional instructions for the occupation of the Zamboanga Peninsula and the Sulu Archipelago.2
The success of the Palawan, Zamboanga, and Sulu operations would not only assure a more effective blockade of the South China Sea and provide adequate air support for the invasion of Borneo but would also result in the creation of a virtually complete aerial blockade of the East Indies and southeast Asia, assuming the success of concurrent offensives by forces of the Southeast Asia Command.3 Moreover, these opening offensives would draw a ring around the Japanese in the rest of the Southern Philippines, leaving them isolated and without chance of reinforcement or escape.
MacArthur intended that operations to clear the other islands would begin as soon as possible after the landings on Palawan and the Zamboanga Peninsula. The remaining islands--including Mindanao east of the Zamboanga Peninsula--had no strategic importance in the campaign for the recapture of the Philippines and the East Indies, but pressing political considerations demanded their immediate recapture as well. These subsequent offensives would be directed toward the seizure of Philippine real estate as such. They were designed for the purpose of liberating Filipinos, re-establishing lawful government,
and destroying Japanese forces.
The Southern Philippines Campaign would entail a series of amphibious operations by forces ranging in size from reinforced regimental combat teams to a corps of two divisions. The amphibious assaults would differ little from previous operations in the Southwest Pacific Area except that Army amphibians and landing craft would execute much of the ship-to-shore movement and land-based planes would provide all air support. MacArthur had already returned to Admiral Nimitz all the CVE's and a large percentage of the amphibious lift that Nimitz had transferred to the Allied Naval Forces, SWPA, for the Leyte, Mindoro, and Luzon invasions, and these vessels Nimitz was employing for the Iwo Jima and Okinawa operations. The Allied Naval Forces, moreover, had to use much of the shipping remaining available to it on resupply runs to various Luzon beaches. Fire support ships left to the Allied Naval Forces consisted of only a few cruisers and destroyers. Nevertheless, the Allied Naval Forces, SWPA, had sufficient means at least to launch the campaign in the Southern Philippines. To find shipping for operations after the seizure of Palawan and Zamboanga, the Allied Naval Forces would judiciously stagger invasion target dates and transfer south vessels no longer needed to support Sixth Army on Luzon.
Major units available to General Eichelberger's Eighth Army for the reoccupation of the southern islands included X Corps headquarters, the Americal Division, the 24th, 31st, 40th, and 41st Infantry Divisions, and the separate 503d Parachute RCT. As of early February X Corps headquarters was on Leyte, while the Americal Division was split between that island and Samar.4 The bulk of the 24th Division was on Mindoro, where divisional units originally committed on Luzon were also to be concentrated, along with the 503d RCT. The 31st Division had one RCT at Sansapor in northwestern New Guinea; the rest of the unit was on Morotai Island, between Mindanao and New Guinea.5 The 40th Division, previously with Sixth Army, was relieved of its combat missions on Luzon in late February. Originally, the 41st Division had been scheduled to reinforce Sixth Army, but had stopped at Mindoro after General MacArthur decided to speed the reconquest of the Southern Philippines.6 Eighth Army was also to employ most of the 2d and 3d Engineer Special Brigades, the components of which were scattered among many New Guinea, Morotai, Leyte, Mindoro, and Luzon bases. Normal reinforcing units, such as artillery and tank battalions, amphibian tractor and truck companies, and service organizations of all types, would assemble at various New Guinea and Philippine ports for attachment to the infantry divisions operating in the southern islands.
Air support was, of course, the responsibility of the Allied Air Forces, Southwest Pacific Area.7 Allied Air Forces
delegated this responsibility to the Thirteenth Air Force, which, under the command of Brig. Gen. Paul B. Wurtsmith, was based principally on Morotai and Leyte. Mindoro-based aircraft of the Fifth Air Force would also support the Palawan and Zamboanga invasions, and the Fifth would reinforce the Thirteenth as necessary during subsequent attacks. After the first landings, much of the support for later invasions and almost all the close support of ground operations would be executed by Marine Air Groups 12 and 14, based on Leyte and Samar in February, and by Marine Air Groups 24 and 32, which would redeploy to Zamboanga from Luzon.
Eighth Army expected to employ guerrillas to the maximum, and on many of the southern islands well-developed guerrilla forces existed. On Mindanao, once the target for the initial invasion of the Philippines, guerrillas under Col. Wendell W. Fertig, a U.S. Army reservist, had been carefully nurtured, submarine and aircraft supplying them with arms, ammunition, and other necessities. Colonel Fertig had over 33,000 on his rolls in February 1945, some 16,500 of them armed. As commander of the 10th Military District, Fertig had grouped his forces into six divisions--organized more or less along the lines of a prewar Philippine Army division--and the Maranao Militia Force, a loosely organized "division" composed of Moros.
Similar to the 10th Military District guerrillas in effectiveness and degree of organization was the 6th Military District, a guerrilla force on Panay commanded by Col. Marcario L. Peralta of the Philippine Army. Activities of potentially strong guerrilla organizations on Negros and Cebu were somewhat inhibited by the size and aggressiveness of Japanese garrisons on those two islands. The Negros guerrillas were commanded by Lt. Col. Salvador Abcede, Philippine Army, and those on Cebu by Lt. Col. James M. Cushing, an American civilian who had been a mining engineer in the Philippines before the war. Bohol had a weak guerrilla organization under Maj. Ismael P. Ingeniero, Philippine Army, and small, relatively ineffective guerrilla units existed on Palawan and on the islands of the Sulu Archipelago.8
Until February 1945, military intelligence had been the principal contribution of guerrilla units in the Southern Philippines. Nonetheless, the organizations were enthusiastically willing, however limited their capabilities, to provide combat reinforcements to Eighth Army's divisions. The guerrilla units had some preassault missions such as cutting Japanese overland lines of communications, clearing prospective beachhead areas, and attempting to bottle Japanese forces into small areas.
The Japanese in the Southern Philippines
The Japanese forces on the southern islands were under the control of the 35th Army, which had conducted the defense
of Leyte.9 In February 1945 General Suzuki, commanding 35th Army, still had his headquarters on Leyte, but with the approval of General Yamashita had already begun an attempt to evacuate the best of the troops left on Leyte to Negros, Cebu, Panay, and Mindanao Islands. Yamashita, of course, had long since written off the Southern Philippines, having neither the intention nor the capability of sending reinforcements to the islands. His instructions to Suzuki mirrored the 14th Area Army's concept for the defense of Luzon--35th Army would pin down for as long as possible as many Allied divisions as it could.
Suzuki planned to make his stand in east-central Mindanao, where he hoped to set up a little self-sustaining empire that could hold out indefinitely. For this purpose he would use the 30th and 100th Divisions, already deployed in that portion of Mindanao lying east of the Zamboanga Peninsula, as well as a large body of naval troops stationed in the same area. He made no plans, apparently, to redeploy other forces in the southern islands to eastern Mindanao. The 54th Independent Mixed Brigade and attached naval units would continue to hold the Zamboanga Peninsula, and the 55th IMB would remain along the Sulu Archipelago, concentrated on Jolo Island. The 102d Division would continue to garrison Panay, Negros, Cebu, and Bohol. About half of the 102d Division had been sent to Leyte, but Suzuki anticipated that strong reinforcements would reach the unit from Leyte. His plans made no provision for sending Leyte evacuees to Zamboanga, Palawan, or the Sulu Archipelago, although he apparently hoped that elements of the 30th Division could return to Mindanao.10
Suzuki's attempts to evacuate Leyte ended in dismal failure. In the first formal effort, undertaken in mid-January, about 750 men of the 1st Division managed to get across the Camotes Sea from northwestern Leyte to northern Cebu. Thereafter, Allied aircraft and PT boats prevented the 20,000 Japanese still alive on Leyte from undertaking large-scale evacuation, although about 1,000 Japanese of various units, in every conceivable type of small craft, did make their way to Cebu during the next two or three months. Suzuki himself reached Cebu in mid-March, but lost his life a month later as he attempted to sail on to eastern Mindanao. His chief of staff, Maj. Gen. Yoshiharu Tomochika, reached Mindanao in late April after an epic trip from Cebu in a small sailing vessel.
By February 1945 the time was long past when the Japanese on the southern islands could hope for anything more than to die while conducting a static defense. There were over 102,000 Japanese
on the islands, including approximately 53,000 Army ground combat and service troops; 19,400 men of the Army air forces, almost all of the service category; 15,000 naval personnel, mostly of service units; and 14,800 noncombatant civilians. The total included few more than 30,000 trained ground combat effectives--infantry, artillery, armor, and combat engineer troops. The units were scattered over many islands, all were understrength, and most were relatively poorly equipped. Moreover, they were psychologically ill prepared for large-scale fighting. As a result of preoccupation with the Leyte operation, Suzuki, who was also plagued by communications difficulties, had been unable to exercise effective control over the units in the Southern Philippines for some months. It further appears that most of the unit commanders did not expect American forces to make a major attempt to retake the Southern Philippines in the near future. Rather, remembering how large Japanese concentrations had been bypassed previously during the Pacific war, they believed that the Southern Philippines might be forgotten as the Allies moved toward Japan or the Indies; that, at most, U.S. Army formations might seize the principal port cities; and that advances inland would probably be undertaken by guerrillas, with whom the Japanese felt they could cope almost indefinitely.
The Japanese in the Southern Philippines, therefore, apparently felt quite secure if not downright complacent. Such an outlook would be dangerous enough if shared by first-class troops; it was doubly so when held by the types of units comprising the bulk of the forces in the southern islands. The 54th and 55th IMB's, for example, had been formed in the Philippines in 1943 from a confusion of garrison units, replacements, and a miscellany with no combat experience. The 100th and 102d Divisions were not organized until mid-1944, having then been expanded from two independent mixed brigades formed about the same time and in much the same manner as had the 54th and 55th IMB's. Indeed, the progenitor of the 102d Division had been on garrison duty on Mindanao since early May 1942. Probably the best unit, at least on paper, was the 30th Division, which had formed in Korea during 1943 from elements of three "regular" divisions that had had considerable combat experience. The division, however, had lost about half its combat strength on Leyte, and the nature and extent of the unit's defensive preparations on Mindanao raise some doubts as to the quality of the leadership within the organization. The best defenses were those of the 54th IMB at Zamboanga and of the 102d Division at Cebu City, Cebu.
Most of the Japanese units in the Southern Philippines had enough military supplies to start a good fight, but far from enough to continue organized combat for any great length of time. The most glaring weakness, painfully evident to the Japanese commanders, was a shortage of artillery ammunition. Wheeled transport was also at a premium, the guerrillas and the Allied Air Forces having destroyed most of the trucks that had once been available to the Japanese on the southern islands. Certain classes of medical supplies, especially malaria preventives, were also short, and there were not enough arms to supply all the available service units,
let alone the able-bodied male Japanese civilians who could have been drafted into the armed services. Food was plentiful in the settled areas, but once forced into the mountainous interiors of the islands in the Southern Philippines, 35th Army would face food shortages similar to those that were so debilitating the 14th Area Army on Luzon. As was the case on Luzon, the Japanese in the Southern Philippines, given their determination not to surrender, faced only one end--death by combat, starvation, or disease.
Airfields on Palawan
Designated by Eighth Army as the unit responsible for executing the ground phases of the Palawan, Zamboanga, and Sulu Archipelago operations, the 41st Division, Maj. Gen. Jens A. Doe commanding, organized the Palawan Force for the seizure of Palawan Island.11 Palawan Force was commanded by Brig. Gen. Harold Haney, the assistant commander of the 41st Division; its principal combat component was the 186th RCT, under Col. Oliver P. Newman. Antiaircraft units, engineers assigned to airfield construction, and normal service force attachments made up the rest of the force, which numbered approximately 8,150 men. Palawan Force loaded at Mindoro aboard the ships of Admiral Fechteler's Task Group 78.2, and left Mindoro on the evening of 26 February in the company of the supporting cruisers and destroyers of Task Group 74.2 under Rear Adm. Ralph S. Riggs.
Following half an hour of naval gunfire, assault waves of the 186th Infantry landed unopposed along the northern shore of Puerto Princesa harbor, east-central Palawan, about 0850 on 28 February. (Map 27) The regiment occupied the town of Puerto Princesa, at the northwest corner of the harbor entrance, about 1030 against no resistance, secured two airstrips immediately east of the town before noon, and marched to the western and southern shores of the harbor late in the afternoon. The 186th did not sight a single Japanese during the day and found none on 1 March as its troops combed all the flat land in the Puerto Princesa area and established a defensive perimeter to assure the safety of the airfields, where engineers had already started work.
The Japanese garrison on Palawan numbered about 1,750 men and was built around two rifle companies from the 102d Division, to which some 900 Air Force and 250 Navy troops were attached. The only significant organized resistance conducted by the garrison was confined to hills ten miles north-northwest of Puerto Princesa. During the period 3-8 March, elements of the 186th Infantry reduced two or three fanatically defended strongpoints in those hills, and thereafter operations on Palawan devolved into a series of far-flung amphibious and overland patrols the 186th Infantry and guerrilla units conducted. The Japanese were interested primarily in avoiding contact and fought only when cornered. As a result, the task of clearing Palawan--270 miles long northeast to southwest and about 20 miles across--was impeded mainly by rough, trackless terrain and the distances involved.
Palawan Force also reconnoitered many offshore islets, finding no Japanese
Clearing Puerto Princesa Harbor
28 February-1 March 1945
on some and quickly clearing others. American infantry occupied Dumaran Island, off the northeast coast, on 9 March; secured Coron and Busuanga, between Palawan and Mindoro, against negligible resistance from 9 to 17 April; and cleared Balabac and Pandanan Islands, off Palawan's southwestern tip, during the period 12-21 April. By 21 April all elements of the 186th RCT except for the 2d Battalion, 186th Infantry, and the regimental Cannon Company had left for Mindanao. The remaining units, protecting the new air base, stayed on Palawan until 4 July, when elements of the 368th Infantry, 93d Division, relieved them. To that date U.S. Army forces on Palawan had lost about 10 men killed and 45 wounded. Japanese losses had been 890 killed or found dead and 20 taken prisoner.
Airfield construction on Palawan did not proceed as rapidly as planned.12 Originally, the Allied Air Forces had hoped to ready a 5,000-foot dry-weather strip by 5 March, in time to provide air support for the landing on the Zamboanga Peninsula. An all-weather field, 7,000 feet long, was also to be constructed in the Puerto Princesa area. However, after inspecting the airfield sites, Thirteenth Air Force engineers concluded that the soil in the area compacted so poorly that it would take an inordinately long time to prepare a dry-weather strip. Accordingly, the engineers repaired and extended a concrete-paved Japanese strip already some 4,500 feet long. So much work was necessary at this field that it was not operational until 20 March, too late for any Palawan-based aircraft to help support the Zamboanga landings. Later, however, planes from Palawan provided some support for operations in eastern Mindanao and on Borneo. Allied Air Forces bombers from Palawan, as planned, covered vast reaches of the South China Sea and struck at targets along the Indochina and southern China coasts. Water-based and land-based patrol bombers of the Allied Naval Forces, also stationed at Puerto Princesa, co-operated in the air effort to cut the Japanese lines of communication to the Indies by flying search and combat missions over the South China Sea. Although the war ended before the Palawan air base came to serve all the purposes for which it was intended, the strategic value of the air base seemed well worth the small price paid for its seizure.
Securing the Airfield Area
The fact that a fighter strip was not ready at Palawan as early as planned complicated preparations for air support at Zamboanga, since Eighth Army and the Allied Naval Forces considered it essential to have aircraft based closer to Zamboanga than Mindoro, Leyte, and Samar.13 The problem was solved in a somewhat novel manner. Troops of the guerrilla 105th Division, Col. Hipolito Garma commanding, had long held a good, prewar landing strip at Dipolog,
on the north coast of the Zamboanga Peninsula 145 miles from the peninsula's southern tip.14 Allied Air Forces planes taking supplies to Fertig's guerrillas had been using the field since late 1944; the field had also been the site of many emergency landings by American aircraft. The field was known to be capable of accommodating at least one squadron of fighters. The Thirteenth Air Force therefore decided to send a squadron from Marine Air Group 12 to Dipolog to supplement the air support that could be provided from other available bases.
To strengthen the guerrilla garrison at Dipolog during the critical support period, two reinforced companies of the 21st Infantry, 24th Division, flew in from Mindoro on 8 March aboard C-47's. On the same day sixteen Marine Corsairs arrived. The Marine planes flew cover for the naval bombardment and for mine sweeping groups that began operating off Zamboanga on 8 March, two days before the amphibious assault; augmented air cover for the attack convoy, which departed Mindoro and Leyte the same day; and helped provide close support for operations ashore at Zamboanga from 10 to 15 March. The planes then left Dipolog for Zamboanga. The 21st Infantry's two companies evacuated by C-47 before the end of the month.
Colonel Fertig had informed Eighth Army that unopposed landings could be made in the vicinity of Zamboanga City, and underwater demolition teams, engineers, and guerrillas had with impunity marked the landing beaches on 9 March. Nevertheless, the Allied Naval Forces executed preassault bombardments against landing beaches in the Zamboanga vicinity as scheduled on 8, 9, and 10 March.15 The bombardment vessels--and accompanying mine sweepers--received fire from a few Japanese 75-mm. artillery weapons emplaced on high ground two to three miles inland, but suffered no damage. The bombardment covered the landing beaches thoroughly and reached inland to knock out some of the Japanese
artillery. The mine sweepers had no trouble clearing Basilan Strait, between the Zamboanga Peninsula and Basilan Island, twelve miles south. Meanwhile, Rear Adm. Forrest B. Royal's Task Group 78.1, with the 41st Division less the 186th RCT aboard, sailed south and entered Basilan Strait from the west early on 10 March.
Troops of the 162d Infantry landed virtually unopposed about 0915 near barrio San Mateo, four and a half miles west-northwest of Zamboanga City. (Map 28) Light machine gun fire greeted the regiment's leading assault wave, and artillery and mortar fire from the inland high ground harassed later echelons, but no casualties resulted. By 1015 the regiment had secured Wolfe Field, an abandoned prewar strip located half a mile inland, and had begun spreading out to the west, north, and east. The 163d Infantry started ashore about 0935 and two hours later had reassembled to strike eastward toward Zamboanga City. Opposed by sporadic long-range rifle, machine gun, and mortar fire, the 163d halted for the night a mile northwest of the city. Meanwhile, the 162d Infantry drove inland a mile and a half and westward along the southern shore of the peninsula for a like distance.
As implied by Fertig's promise of unopposed landings, the 54th Independent Mixed Brigade had abandoned excellent defensive positions along the southern shore of the Zamboanga Peninsula and, leaving only a few outposts behind, had withdrawn to elaborate new positions in good defensive terrain in high ground two to three miles inland.16 From this rising ground Lt. Gen. Tokichi Hojo, commander of the 54th IMB and all other Japanese Army and Navy troops in the Zamboanga area--about 8,900 men in all--had complete observation of the airfield and beachhead area the 41st Division had taken.
Since the Japanese had withdrawn, the 162d and 163d Infantry Regiments had no trouble securing the remainder of the coastal plain by dusk on 11 March. That day troops of the 162d reached Caldera Bay, a former Japanese seaplane base eight miles west-northwest of Zamboanga City; other troops of the regiment pushed inland to Malisay, two miles north of the landing beaches, and to the vicinity of San Roque, a mile and a half southeast of Malisay. The 163d Infantry, meanwhile, secured Zamboanga City against negligible opposition, finding that preinvasion air and naval bombardment--which had probably been unnecessary--had practically leveled it. The 163d also overran Japanese-built San Roque Airfield, a mile and a half northwest of Zamboanga and about the same distance east of Wolfe Field. Since the San Roque strip was in better condition and could be more easily extended than Wolfe Field, the 873d Engineer Aviation Battalion immediately set to work to prepare a dry-weather runway at San Roque. The engineers completed the strip to a length of 5,000 feet late on 15 March.
Clearing the Peninsula
Having secured the Zamboanga coastal plain, the 41st Division faced the problem
The Seizure of Zamboanga
41st Infantry Division
10-31 March 1945
AMPHIBIOUS LANDING AREA, ZAMBOANGA PENINSULA
of driving the Japanese from the high ground overlooking the airfield area. To accomplish its share in this task, the 163d Infantry struck generally north from Zamboanga City astride the Tumaga River valley, its ultimate objective Mt. Pulungbata, five miles inland. The 162d Infantry advanced in two columns, the right flank striking north from the vicinity of San Roque and the left driving north from Malisay. The regimental objective was Mt. Capisan, a mile and a half north of Malisay.
Guerrillas had an important share in the plan of offense. Three years earlier, when the Japanese invaded the peninsula, the small Fil-American garrison at Zamboanga had withdrawn up the east coast of the peninsula to the vicinity of Belong, eighteen miles north-northeast of the city. Holding excellent defensive terrain in the Belong area, the garrison had assembled supplies in anticipation of conducting guerrilla warfare but had simultaneously kept open a line of retreat northward and northeastward to permit ultimate escape into eastern Mindanao. The general surrender in the southern Philippines came before the Fil-American force had much opportunity
to put either guerrilla warfare or escape plans into effect.17 To prevent the Japanese from repeating the projected Fil-American maneuver of 1942, Eighth Army directed Colonel Fertig's forces to block the east coast road in the Belong area, a task Fertig entrusted to Capt. Donald J. LeCouvre's 121st Infantry, 105th Division.18
The two regiments of the 41st Division faced arduous tasks. General Hojo's troops held excellent defenses in depth across a front five miles wide, some portions of the line being three miles deep. All installations were protected by barbed wire; abandoned ground was thoroughly booby-trapped; mine fields, some of them of the remote-control type, abounded; and at least initially the 54th IMB had an ample supply of automatic weapons and mortars. While Japanese morale on the Zamboanga Peninsula was not on a par with that of 14th Area Army troops on Luzon, most of the 54th IMB and attached units had sufficient spirit to put up a strong fight as long as they held prepared positions, and Hojo was able to find men to conduct harassing counterattacks night after night. Finally, the terrain through which the 41st Division had to attack was rough and overgrown, giving way on the north to the rain forests of the partially unexplored mountain range forming the backbone of the Zamboanga Peninsula. Only poor trails existed in most of the area held by the Japanese, and the 41st Division had to limit its advance to the pace of bulldozers, which laboriously constructed supply and evacuation roads. Once the American troops entered the peninsula's foothills, tanks could not operate off the bulldozed roads.
Behind continuous artillery fire and with exceptionally close support from Marine Corps planes, the 41st Division's two regiments pushed slowly but steadily northward after 11 March. On the 20th the 54th IMB's prepared defenses finally began to disintegrate, and on or about the 23d the 41st Division drove a wedge between the Japanese defensive units in the Mt. Pulungbata and Mt. Capisan sectors. On the 25th the 162d Infantry overran the last organized resistance in the vicinity of Mt. Capisan, forcing northward the remnants of the central of three defense units that Hojo had organized. The western unit, originally holding the hills north of Caldera Bay, had not yet been subjected to much pressure, but had been seriously weakened by transfers of troops to reinforce the center and eastern sectors. The eastern unit had, meanwhile, lost heavily in the face of steady progress on the part of the 163d Infantry.
On 26 March the 186th Infantry (less its 2d Battalion, on Palawan) began to relieve the 163d Infantry on the east. On 30 and 31 March the relatively fresh 186th extended the front to the east and drove rapidly northward against diminishing opposition. Realizing that it was no longer possible to continue effective resistance, General Hojo ordered a retreat late on the 31st, and before dark on 1 April all forces under his command had
begun withdrawing northward. Their logical route of withdrawal--up the east coast--blocked by the guerrilla 121st Infantry at Bolong, the Japanese had to strike into the wild interior of the peninsula. 41st Division and guerrilla patrols pursued. Physical contact between patrols of the 121st and 186th Infantry Regiments in a river valley two miles north-northeast of Mt. Pulungbata on 2 April marked the end of effective Japanese resistance in the Zamboanga area.
After 2 April 41st Division troops and guerrillas continued patrolling throughout the Zamboanga Peninsula, hunting down Japanese concentrations wherever and whenever reported. Organized remnants of the 54th IMB, facing incredible hardships, first made their way across the rough mountains to Sibuko Bay, on the west coast thirty miles north of Zamboanga City. Chased from this area in late April, some units struck northward another thirty miles to Siocon Bay, while others headed east across the peninsula and then turned north. By the end of the war almost all survivors had gathered in the north-central part of the peninsula about midway between Zamboanga and Dipolog, where elements of the guerrilla 105th Division contained them.
When the 54th IMB began its general retreat in early April, it had left nearly 5,000 of its original 8,900 troops. Approximately 1,385 men of the retreating force survived the war, joining about 1,100 more who were captured before 15 August. Thus, roughly 6,400 Japanese were killed or died of starvation and disease on the Zamboanga Peninsula. The casualties of the 41st Division were about 220 men killed and 665 wounded to early July, when the 368th Infantry, 93d Division, took over on the peninsula.
The Sulu Archipelago
Operations to clear the Sulu Archipelago, where additional airfields were to be constructed, began well before organized resistance ceased on the Zamboanga Peninsula.19 On 16 March a reinforced company of the 162d Infantry landed unopposed on Basilan Island and during the next two days combed Basilan and offshore islets, finding no signs of Japanese. Two guerrilla companies then took over garrison duties on Basilan to provide security for an Allied Naval Forces PT-boat base on the northwest shore. (Map 29)
The next invasion along the Sulu Archipelago coincided with the collapse of 54th IMB resistance on the Zamboanga Peninsula. On 2 April the reinforced 2d Battalion, 163d Infantry, landed on Sanga Sanga Island of the Tawitawi Group, 200 miles southwest of Zamboanga and less than 40 miles from the coast of Borneo. A little ineffective mortar and machine gun fire from a nearby islet, Bangao, was the only opposition, and by 6 April the battalion had cleared both Bangao and Sanga Sanga at the cost of 2 men killed and 4 wounded, the Japanese losing about 30 men killed. The Japanese had already withdrawn from Tawitawi Island,
The Sulu Archipelago
which guerrillas had controlled since mid-March.
In jumping from Zamboanga to the Tawitawi Group, the 41st Division had bypassed the only significant concentration of Japanese along the Sulu Archipelago. On Jolo Island, about midway between Zamboanga and Tawitawi, the garrison included approximately 2,400 men of the 55th IMB, 1,000 Army Air Force personnel, and 350 Japanese naval troops. As at Zamboanga, the Japanese on Jolo Island made no serious effort to defend the beaches, and about 0845 on 9 April the reinforced 163d RCT (less 2d Battalion, 163d Infantry) landed against no resistance near Jolo Town, on the island's northwestern shore. By evening on 11 April the 163d Infantry had driven Japanese forces off heights immediately south and southeast of the town and had secured a nearby airstrip.
Having retired to hill masses farther inland where defenses had been long in preparation, the Japanese began to resist stubbornly. One concentration was located at Mt. Daho, six miles southeast of Jolo, and another on Mt. Tumatangus, about the same distance southwest of the town. Attacks against the Mt. Daho defenses began on 15 April, local guerrillas under Col. Alejandro Suarez, Philippine Army, leading off. Since the guerrillas alone were unable to reduce the Japanese positions, the 1st Battalion of the 163d Infantry joined the fight. Artillery support and close air support by Zamboanga-based Marine Corps planes enabled the combined 163d Infantry and guerrilla force to overrun the Japanese defenses on 22 April. Some of the defenders escaped westward to Mt. Tumatangus, where guerrillas and the 3d Battalion, 163d Infantry, began an attack
on 25 April. These troops reduced most of the prepared defenses at Mt. Tumatangus by 2 May, and operations on Jolo Island passed to the mopping-up stage.
Some organized resistance continued in the Mt. Tumatangus area into July, when the remaining Japanese attempted to move to the eastern end of Jolo. Meanwhile, the bulk of the 163d RCT had pulled out of action and the last elements left Jolo for Mindanao on 19 June, to be replaced by troops of the 368th Infantry, 93d Division, and Colonel Suarez' guerrillas. The 163d RCT lost approximately 35 men killed and 125 wounded on Jolo to mid-June, by which time the Japanese had lost over 2,000 men killed. Less than 90 of the Japanese not killed or captured by mid-June survived to surrender after the end of the war.
Zamboanga-Sulu Airfield Development
While the landing on Jolo Island marked the end of the most significant action of the ground phase of the Zamboanga-Sulu Archipelago operation, the strategic purposes for which the operations had been designed were not satisfied until planned airfield construction had been completed.20 The first field at Zamboanga was a dry-weather strip 5,000 feet long, completed on 15 March and immediately put to use by Marine Corps planes. The field, named Calarian Drome, could not answer the need for an all-weather strip 6,000 feet long. Accordingly, engineers constructed a new strip, which the Marine aviators based there called Moret Field, about a mile to the east, and had it ready for all-weather operations by 16 May. Used primarily by Marine Air Groups 12, 24, and 32, Moret Field was also employed by a Thirteenth Air Force night-fighter squadron, an emergency rescue squadron, and Thirteenth Air Force B-24's and P-38's staging through for strikes against Borneo. Marine Corps planes on 16 March executed the first support mission flown from a field in the Zamboanga area, covering the landing on Basilan Island. Later, Marine Corps planes from Zamboanga flew support for the Tawitawi and Jolo operations and undertook preassault bombardment and cover for the invasion of eastern Mindanao. While Thirteenth Air Force planes executed most of the support for the invasion of Borneo, Marine Corps B-25's from Zamboanga also flew some missions.
At Sanga Sanga Island there was a Japanese coral-surfaced strip about 2,800 feet long. Engineers repaired and extended this strip to a length of 5,000 feet by 2 May, when fighters of the Thirteenth Air Force began moving to Sanga Sanga from Palawan to provide close support for the initial landings on Borneo. These U.S. Army planes were replaced in mid-May by units of the Royal Australian Air Force, which employed the all-weather Sanga Sanga field during later operations on Borneo. Finally, a Japanese field 3,800 feet long on Jolo Island was repaired and used for aerial supply and evacuation operations in support of ground troops throughout the Sulu Archipelago.
Planes based at both Zamboanga and Sanga Sanga were to have had a share in the air support of post-Borneo operations in the Indies, and preparations for these operations were well along when the war ended. As it was, the Zamboanga and Sanga Sanga fields had already assumed greater importance for operations in the Indies than originally contemplated. Engineering problems at the first Borneo landing areas were such that airstrips on that island were not ready in time to provide support for subsequent Borneo operations, so the Philippine fields had to serve instead. Strategically and tactically, the Zamboanga and Sanga Sanga fields had proved invaluable, and in the process of seizing the sites for these fields Eighth Army had liberated some 250,000 Filipinos.
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1. General background sources for this subsection are: GHQ, SWPA, Basic Outline Plan for MUSKETEER Opns (MUSKETEER I), 10 Jul 44; MUSKETEER II, 29 Aug 44; MUSKETEER III, 26 Sep 44; GHQ, SWPA, PRINCETON Basic Outline Plan for Reoccupation of the Visayas-Mindanao-Borneo-NEI Area (PRINCETON I), 31 Oct 44; PRINCETON II, 20 Nov 44; MONTCLAIR III (redesignation of PRINCETON), 25 Feb 45. Copies of these plans are to be found in various files of the Operations Division, War Department; they were employed by the present author in preparing an unpublished manuscript, The Philippine Campaign, 1944-45, while a member of the G-3 Historical Division of GHQ SWPA-GHQ AFPAC in 1944-46 (copy in OCMH files), portions of which are published in United States Strategic Bombing Survey, Military Analysis Division, Employment of Forces Under the Southwest Pacific Command (Washington, 1947). Further background information is in Chapters I and II, above. See also, Cannon, Leyte, ch. I.
2. GHQ SWPA OI's 89 and 91, 6 and 14 Feb 45, G-3 GHQ Jnl Files, 6 and 14 Feb 45.
3. See Romanus and Sunderland, Time Runs Out in CBI, Ch. X.
4. See above, ch. XXIII, and Cannon, Leyte, p. 365.
5. See Smith, Approach to the Philippines, pp. 480-93.
6. See above, ch. XX. The 41st Division staged at Biak, where the unit had been since late May 1944. See Smith, Approach to the Philippines, chs. XII-XVI.
7. Additional information on air support planning is from: Craven and Cate, AAF V, pp. 448-58; Boggs, Marine Aviation in the Philippines, pp. 108-14.
8. General information on guerrilla units throughout the chapters on the Southern Philippines operations is from: G-2 GHQ FEC, The Guerrilla Resistance Movement in the Philippines, passim. Additional information on Mindanao guerrillas is from Historical Record, Mindanao Guerrilla Resistance Movement, Tenth Military District, From 16 September 1942 to 30 June 1945 (hereinafter cited as Mindanao Guerrilla Record), pp. 39-60.
9. The main sources for this subsection are: Tomochika, True Facts of the Leyte Opn, pp. 33-39; 10th I&H, Staff Study of Operations of Japanese 102d Div on Leyte and Cebu, Background Notes, pp. 2-5; ibid., Org of the 102d Div, p. 5; ibid., Dispositions of the 102d Div, Jan-Apr 45, pp. 1-2; 10th I&H Staff Study of Operations of the Japanese 35th Army on Leyte, pt. I, Narrative of Maj Gen Yoshiharu Tomochika, pp. 11-12; 10th I&H, Staff Study of Japanese Operations on Mindanao, Narrative of Maj. Gen Gyosaku Morozumi (CG 30th Div), pp. 2-3, 6; ibid., Narrative of Lt Gen Jiro Harada (CG 100th Div), pp. 3, 7-8, 11; 10th I&H, Staff Study of Japanese Operations in Zamboanga, Narrative of Maj Yasura Hanada (CofS 54th IMB), p. 1; 14th Area Army Tr Org List. Copies of all foregoing documents are in OCMH files. See also, Cannon, Leyte, pp. 365-67.
10. See apps. F and G.
11. The principal source for this section is 10th Information and Historical Service, Operational Monograph on the Palawan Operation, pages 16-82.
12. Information about airfield construction and air operations from Palawan is from: 10th I&H Opnl Monograph Palawan, pp. 21, 65; Eighth Army Rpt Palawan and Zamboanga Opns, pp. 15, 115-16, 118; Craven and Cate, AAF V, pp. 453-54, 461, 465.
13. The story of providing air support for the Zamboanga assault is derived from: Craven and Cate, AAF V, pp. 454-55; Boggs, Marine Aviation in the Philippines, pp. 112-14; 10th I&H, Operational Monograph on the Zamboanga-Sulu Archipelago Operation, pp. 31-32; Mindanao Guerrilla Record, passim.
14. Garma was a former Philippine Constabulary officer. The Dipolog field was garrisoned by the 105th Division's 107th Infantry, commanded by Maj. Marcelo Bonilla, PA.
15. The remainder of the story of clearing the Zamboanga Peninsula is based mainly on: 10th I&H Opnl Monograph Zamboanga-Sulu Archipelago Opn, pp. 9-10, 27, 32-53, 61-65; Eighth Army Rpt Palawan and Zamboanga Opns, pp. 46-56; Boggs, Marine Aviation in the Philippines, pp. 112-16; Intervs, author with Col Fertig (CO 10th Mil Dist), Lt Comdr (Lt Col, 10th Mil Dist) Sam J. Wilson (CofS 10th Mil Dist), Maj Patrocenio B. Garcia (G-1 10th Mil Dist), and others, Chicago, III., ex-Mindanao Guerrilla Reunion, 26 Jul 56. A tape recording of these interviews, which are hereinafter cited as Fertig Interviews, is in OCMH files.
16. Additional information on Japanese operations on the Zamboanga Peninsula is from 10th Information & Historical Service, Staff Study, Japanese Operations in Zamboanga, passim, which was largely prepared by Major Hanada, chief of staff and later commander of the 54th IMB.
17. Col. A. T. Wilson, Pacific War 1942--The Defense of Zamboanga, in Hist Rpt, Visayan Mindanao Force, Defense of the Philippines, 1 Sep 41-10 May 42, pp. 567-91 (an. XI to Rpt of Opns of USAFFE and USFIP in the P.I., 1941-42), copy in OCMH files; Col. H. W. Tarkington, MS, There Were Others, pp. 230-39, copy in OCMH files.
18. LeCouvre, an unsurrendered Air Forces enlisted man, had joined Fertig's guerrillas in December 1942 and had been in command of the 121st Infantry since August 1944.
19. This section is based largely upon: Eighth Army Rpt Palawan and Zamboanga Opns, pp. 28-29, 41-42, 44, 56-60; 10th I&H, Opnl Monograph Zamboanga-Sulu Archipelago Opn, pp. 10-11, 45-46, 53-61, 63-64, 77; 10th I&H, Staff Study of Japanese Operations on Jolo Island, 9 Apr-16 Sep 45, passim (based mainly on materials supplied by Maj Tokichi Tenmyo, CO 365th IIB 55th IMB); 163d Inf Unit Jnl 6 Apr-20 Jun 45.
20. This subsection is based on: 10th I&H, Opnl Monograph Zamboanga-Sulu Archipelago Opn, pp. 41, 58; Eighth Army Rpt Palawan and Zamboanga Opns, pp. 97, 105, 116; Boggs, Marine Aviation in the Philippines, pp. 114-17, 121-22, 125; Craven and Cate, AAF V, pp. 456, 466; Office of the Chief Engineer, General Headquarters, Army Forces, Pacific, "Engineers of the Southwest Pacific, 1941-1945," VI, Airfield and Base Development (Washington, 1951), 373.