Pacific War 7 – Invasion of Philippines

Pacific War 7 – Invasion of Philippines

Background and Forces

US forces

Philippines, rich islands which United States owned ever since the US-Spanish war, were important to Japanese for many reasons. They were a rich source of raw materials, but more important was their strategic location. Located between Japan and Southeast Asia, Philippines would allow the US Navy to interdict any traffic in the area. Even just military presence in the Philippines could be used to deter Japanese aggression – and military presence there was significant. Conquest of Philippines would also make conquest of Indonesia much easier, as land-based aircraft could be based close to their targets. Nevertheless, some in Washington believed that the Philippines did not represent an object of great strategic value.

US command knew that Philippines could not be defended. Philippines were close to Japan and far from the US mainland, which meant that the Japanese would have advantage in logistics. Moreover, proximity of Japan and its naval bases meant that the Japanese Navy could interdict any attempts to supply or reinforce the islands. Archipelago itself consisted of over 7 000 islands, and the main naval base located in Subic Bay was difficult to defend. Nevertheless, Douglas MacArthur had strong force of 80 000 soldiers, of which 19 000 Americans. Most of the USAFFE consisted of infantrymen, but there was also a large contingent of coastal artillery units used to guard fortifications that protected Manilla and Subic bays. Ground forces in general were predominantly infantry, with some artillery and armored cars, but no tanks. MacArthur also had 277 aircraft, of which 107 modern fighters and 35 flying fortresses – a total of 142 aircraft capable of serious combat. Majority of commanders were American, and they had taken over command and training of most Philippino Army throughout the fight.

While Philippine Army troops were numerous, they lacked modern weapons, training, equipment and experienced commissioned and non-commissioned officers. While MacArthur had envisioned Philippine Army as being based on the Swiss model of a small professional army filled out with disciplined reservists, threat of Japan had forced him to start mobilizing the troops. Lack of time he had to carry out his plans meant that Filipino units had to be mobilized despite lacking training, equipment, uniforms, rations and other necessities. Estimated total strength of PA was 120 000 troops, but soldiers and officers alike lacked training. Diversity of dialects also caused communications issues, and many soldiers lacked basic educations. Lack of trained officers meant that American officers had to assume command of battalion and higher level units as the war progressed.

MacArthur thus, in addition to hastily training the troops, placed much faith in airplane as an equalizer. He hoped that advanced B-17 bombers and fighter aircraft could compensate for his lack of trained and equipped ground forces. Far Eastern Air Force was a small but growing component of the USAFFE. MacArthur had hoped to use the air power to stem the Japanese, and by December 8 the FEAF had a sizable force. Fighters consisted of modern Curtiss P-40 and obsolete Seversky P-35A fighters. In total, there were 277 aircraft, of which 107 P-40B/E, 52 P-35A and 35 B-17C/D. MacArthur also wanted PA to have its own air force. AAF officers and enlisted personnel thus had to train Filipino Air Corps personnel in required tasks, but this was a slow process. By August 1941., PAAC had 500 personnel organized in six squadrons. As new B-17s and P-40s arrived, obsolete aircraft such as B-10 and P-26A were transferred from USAAF to PAAC.

US Navy’s Asiatic Fleet also maintained forward presence in the region. Commanded by Admiral Hart, it had numerous submarines. Available surface units were limited: heavy cruiser USS Houston, light cruiser USS Marblehead, as well as a number of World War I era destroyers gunboats and support ships. Also present was Motor Torpedo Squadron 3 consisting of six patrol torpedo (PT) boats. The Asiatic Fleet also had Patrol Wing 10, consisting of 24 PBY Catalina aircraft and four seaplane tenders. On December 8, most of the destroyers and the USS Marblehead had deployed to Borneo. However, the lack of Navy transportation and escorts limited the ability to reinforce the islands even before the war. Majority of the effort had to be directed to an undeclared, but hot, war in the Atlantic. Main base was at Manilla, but there was also a major base in Olongapo in the Subic bay.

As the war started looking inevitable, United States looked to defense of their positions in the Philippines, Hawaii and elsewhere. On 16th of August, MacArthur received word that Washington would start shipping reinforcements no later than 5th September. These included several tank battalions, 200th Coastal Artillery Regiment for AA support, an ordnance battalion, and more self-propelled, 75mm M1897A4 gun Motor Carriage M3 halftracks capable of providing direct fire support and armor-piercing capability.

75 mm M3 GMC

The 192nd and 194th Tank Battalions came from Army National Guard units and formed the Provisional Tank Group. Group was armed with M3 Stuart light tanks, whose 37 mm guns were highly effective against lightly armored Japanese tanks. MacArthur could count on getting 108 M-3 Stuarts and some M3 75mm M3 halftracks.

MacArthur had also received SCR-270, 272, and 371 air radar-warning units, but only one set was operational at Iba. While 60th and 200th Coastal Artillery Regiments were present, they did not have enough weapons to protect the airfields, the fortified islands at Manila Bay’s mouth, Subic Bay, Manila, and other bases. Anti-aircraft defenses were limited to 24 machine guns at Clark Field and Manilla. FEAF aircraft would have to be protected by a combination of combat air patrols and dispersal of aircraft to secondary airfields.

Japanese forces

Japanese forces in the area were also significant. The Japanese Southern Expeditionary Army, with headquarters in Saigon in French Indochina, consisted of four numbered armies of which 14th was designated for the Philippines operation. Japanese forces had been mobilized and many were already bloodied in China, giving them much needed experience. However, both IJA and IJN had to spread their forces across multiple concurrent operations.

14th Army, which was a designated spearhead of the attack, consisted of 16th and 48th Divisions as well as a garrison unit, the 65th Independent Mixed Brigade. Two divisions and brigade were infantry units, with each division numbering 20 000 troops. Homma also had two tank regiments, two regiments and a battalion of medium artillery, three engineer regiments, five AAA battalions and other support units. The 16th Division had served in Manchuria and fought in Northern China from 1937 to 1939, but had a mixed combat record. It consisted of 9th, 20th and 33rd Infantry Regiments. The 48th Division had a Formosan mixed brigade consisting of 1st and 2nd Formosa Infantry Regiments and the veteral 47th Infantry Regiment which had combat experience from China. Each division also had organic cavalry for reconnaissance, transport, artillery and engineer regiments.

Masaharu Homma

The Imperial Japanese Army Air Force contributed the 5th Army Air Force Division to the Philippines campaign, commanded by Lieutenant General Hideyoshi Obata. This division had 4th Army Air Force Division at its disposal, composed of four sentais (groups). The brigade had various types of bombers, as well as Nakajima Ki-27 Nate fighters which had fixed landing gear and were overall not very good. In fact, they struggled to defeat even the obsolete Allied aircraft they faced early in the war, and limited range meant they could not reach central Luzon from Formosa. Obata could also use the 10th Independent Hikotai. This unit contained Mitsubishi Ki-15 reconnaissance, Mitsubishi Ki-36 air cooperation, and transport aircraft. But much like Ki-27, all IJAAF aircraft had limited range.

The IJN dedicated the 3rd fleet under vice-admiral Ibo Takahashi to support the IJA’s invasion of the Philippines. The fleet was to take the Philippines and later Borneo and the Celebes. Takahashi’s force was to destroy the US naval forces, cover and support the IJA landings, and after the conquest, protect IJA supply lines and reinforcements. Takahashi had light carrier Ryujo available to conduct operations beyond the range of Japanese land-based aircraft. Majority of the fleet consisted of surface combatants: 5 heavy cruisers, 5 light cruisers, 29 destroyers, two seaplane tenders and some torpedo boats and minesweepers. Most cruisers, destroyers and minesweepers were assigned to Surprise Attack Forces consisting of transports. Five attack forces were aimed, respectively, at Aparri, Vigan, Batan Island and Legaspi.

Japanese aircraft carrier Ryujo

IJNAF proved itself very valuable early in the campaign. IGHQ planners assigned the 11th Air Fleet to the campaign consisting of the 21st and 23rd Air Flotillas based in Formosa. The 21st Air Flotilla provided Mitsubishi G4M1 (Betty) and G3M2 (Nell) twin-engine long-range bombers, but more valuable was the 23rd Air Flotilla. This flotilla consisted of fighter forces, whose naval fighters had longer range than the IJAAF ones. IJNAF pilots did fly Mitsubishi A5M4 fixed landing gear fighters, but its most important contribution was the longer range, Mitsubishi A6M2 Zero fighter, which outclassed any FEAF fighter in the Philippines. Out of 304-aircraft strong IJNAF force, 108 were Zero fighters. These could reach targets in central Luzon, including the main FEAF base at Clark Field and Manila.

Opposing Plans

Japan required Philippines as a part of its larger strategy to gain resources required to maintain their empire – which involved a possible war against United States and United Kingdom. As a result, United States and Britain had to be knocked out of the war fairly quickly.

Japanese plan

Japanese overall war plan required them to simultaneously strike against multiple opponents on widely separated fronts so as to avoid being dragged into an unwinnable war of attrition. This meant capturing Philippines and Malaya while simultaneously neutralizing Allied naval forces at Pearl Harbor and Singapore. This will have eliminated any US major bases close enough to conduct a counterstrike, while Britain, focused on Europe, would only resist a potential attack on India.

The plan for the Japanese attack into the Philippines included a combination of air attacks, amphibious landings, and occupation to conquer the islands. Once Philippines had been neutralized, the IJA and IJN could focus onto expanding into Malaya and Dutch East Indies. Attack on the Philippines would begin by neutralizing the FEAF in the Philippines, whose bases had been located through the pre-war reconnaissance. By catching American aircraft on the ground, the Japanese would eliminate a possibility of air attack against Japanese naval units or transport ships.

IJAAF also had problems with short range of its fighters, which meant that Japanese plans prioritized seizure of the airfields in order to make most of what range they did have. In order to do so, Batan Island, as well as Aparri, Vigan and Legaspi had been selected as targets. Once the IJAAF and IJNAF attained air superiority, IJA units would then conduct major amphibious operations in Luzon and Mindanao.

Next phase would then consist of clearing the islands of enemy ground forces. Homma’s focus was on central Luzon, which contained both the greatest concentration of US military forces as well as the capital city, Manilla. In Luzon, IJA ground units would land in the Lingayen Gulf and Lamon Bay. This would allow them to act as pincers, to surround and overcome the American-Filipino forces based there. After defeating them in a decisive battle, IJA would occupy Manila and other vital strategic locations which, in IJA’s eyes, would force American and Philippine capitulation. This would then allow a portion of forces to be redeployed to Malaya and Dutch East Indies. During all of this, IJN would blockade the islands and isolate them from the world.

US defenses

Washington had many concerns regarding the defense of the Philippines. The islands were set to become independent in 1946., and many Army commanders believed islands to be indefensible. Naval commanders valued the Philippines as a naval base, but even they had serious doubts about defensibility of the islands. Due to war against Germany being a priority, any defense of Philippines had to be based on existing forces with no prospect of reinforcement. Naval officers on the Joint Board believed the Japanese could land up to 60,000 men on the Philippines within a week, with another 100,000 a week later. Total Japanese forces could amount to around 300,000 within a month. Such a force could not be stopped by forces that were available on the islands.

Under WPO-3 plan, after limited resistence on Luzon, the American and Filipino forces were to retreat to the Bataan Peninsula with the aim of defending Manila Bay. Harbor defenses in Manila Bay and Bataan would protect the bay’s entrance, allowing the Pacific Fleet to fight its way to the Philippines and reinforce the defenders within six months.

Manila bay

MacArthur believed WPO-3 to be “defeatist”, and insisted on defending on the point of landing instead of immediately withdrawing to Bataan. In order to prevent the enemy from establishing a foothold on Luzon, he placed faith in the untested PA reserve divisions, long-range B-17 bombers, growing fighter force and reinforcements from the mainland. AAF officers also thought a sufficient B-17 force might deter a Japanese invasion since they believed that they could destroy an invasion fleet or hit Japanese bases in Formosa. All of this led Marshall to believe that MacArthur could hold out, if only for a time. MacArthur assumed that any invasion would not take place until April 1942 due to weather conditions. Given this extra time, MacArthur’s forces would have constructed proper beach defenses, trained the PA divisions, and prepared the FEAF to defend the islands.

Admiral Hart however was aware that his small Asiatic fleet stood little chance against IJN and Hart proposed, on September 17, 1941, to deploy most of his surface fleet south of the Philippines and combine it with the Royal Navy. By October 27, Hart had significantly modified his position following discussions with MacArthur; he proposed that his surface fleet operate out of Manila Bay supporting the Army plan. But the Chief of Naval Operations, Admiral Harold Stark, as well as majority of naval officers, believed that defense of the Philippines was a lost cause. Hart thus prepared his surface fleet to retreat south to fight alongside the combined Royal Navy and Dutch ships, while leaving behind torpedo boats and submarines to protect the flanks of ground forces defending the Philippines.


Japanese intended for the first air attack on Philippines to be carried out on 8th December local time (that is, 7th December by Hawaii and US time) at dawn, which meant the attack would happen several hours after the attack on Pearl Harbor. For the campaign Japan assigned 300 naval aircraft and 175 Army aircraft, in addition to carrier-based aircraft. Attack itself would be carried out by two infantry divisions supported by two tank regiments and significant artillery. But thick fog prevented the aircraft from taking off on schedule, and so attack started only several hours later. Americans did expect the Philippines to be attacked, as it was clear their position was threatened. MacArthur had in fact declared a state of readiness as early as 15th November, and Japanese aircraft had been carrying out reconnaissance flights over the islands as late as 5th December. Final warning came when Pearl Harbor was attacked, on December 8 at 2:30 in the morning by Manilla local time.

Despite this, Americans allowed themselves to be surprised. When attack on Pearl happened, an aide woke Hart but nobody informed MacArthur or any other senior Army officer. Despite the ample warning, neither MacArthur nor his commander of aviation, General Brereton, ordered any countermeasures to be carried out.. Only routine patrols had been carried out in the morning, but neither fighters nor anti-aircraft artillery were ready for quick action. While Brereton did initiate planning for a retaliatory B-17 bombing strike against Formosa slated for the morning of 8th December, his request had to go through MacArthur’s chief of staff Brigadier General Richard K. Sutherland. Brereton was also forced to cancel reconnaissance flights due to poor weather conditions, and believed that Japanese would be just as limited by weather.

But while FEAF had been waiting for orders, the weather cleared over Formosa. IJAAF and IJNAF aircraft took of from Formosa at 7:00. At 9:30, Japanese aircraft struck Tuguegarao and Baguo. After the attacks, Japanese aircraft were observed to be heading back north towards Formosa, and an all-clear report was issued at 10:00. B-17s and fighters returned to their bases, and by 11:00 they started landing to refuel. At 11:20, General Brereton finally received approval to mount his raid on Formosa. Yet the main attack was only now approaching, with IJNAF force of 108 G3M2 Nell and G4M1 Betty bombers, plus 84 A6M2 Zero fighters, headed for Clark and Iba.

When Japanese aircraft arrived over Philippines around noon, they found US aircraft on Clark Field and Nichols Field still ordered in neat rows as if on a parade. No attempts had been made to hide the aircraft or mask them, and nine hours after Pearl Harbor it was Philippine airstrips that got bombed. Anti-aircraft artillery was rare and ineffective, and Japanese had a free reign for next 90 minutes. When the attack ended, one third of fighter aircraft and half of the B-17s had been destroyed. Around 50 more aircraft were heavily damaged. Only 17 B-17s remained operational, and the AAF fighter force suffered 53 P-40 and three P-35A losses. Also destroyed were further 25 to 30 older and auxilliary aircraft. Full half of FEAF had been destroyed for the cost of only seven Zeros. Because of these losses, remaining FEAF aircraft had to move south to avoid destruction, leaving defenders at the mercy of Japanese aircraft.

P-35 at Nichols Field?

Two days later – same day, in fact, as the sinking of British squadron at Kuantan – 54 Japanese bombers attacked Cavite, the main naval base of the Philippines. As they had no need to fear American aircraft, attack was carried out by the book and the entire base was completely destroyed, including submarine torpedo supply as well as submarine Sealion. Damage however was far less than it could have been, as the US commander of the Far Eastern Fleet, Admiral Hart, had withdrawn his weak squadron from the base. In total, he managed to save 3 cruisers, 1 old aircraft carrier and 12 destroyers, as well as 200 000 tons of merchant ships. Separating several destroyers to escort merchantmen to safety, he led remaining ships to Java in order to reinforce defences of Dutch Indonesia. On Philippines he left submarines, 9 torpedo boats, as well as auxilliary ships. These weak naval forces successfully protected flanks of the ground troops during fighting in the Philippines.

Japanese fleet assigned to carry out the invasion was sailing to Philippines despite the bad weather which damaged several ships. Especially landing ships, carrying 120 soldiers each and equipped with a ramp on the prow, had a very bad time. But with no danger of attack, bad weather could be dealt with, and on 10th December Japanese started landing troops on the north of Luzon. A total of 154 ships with troops and equipment were assigned to the operation, directed to land troops at multiple places in short period of time. Main landings were at Aparri, Vingan and Lingayen Gulf. At Aparri, the IJN First Surprise Invasion Force started off-shore operations at 10th December, but the weather interfered. Only two companies landed unopposed at Aparri, while the rest of Tanaka Detachment came ashore 20 miles to the east. In any case, Japanese faced no resistance. The next day, the 50th Sentai, composed of about 36 Ki-27s, was operational from Aparri.

Japanese landings

When Japan’s Second Surprise Force attempted to disembark at Vigan, they were noticed by a P-40 which radioed their position. Attack by FEAF B-17s and P-40s then thwarted the main invasion attempt for a day, though some units managed to sieze Vigan. The next day, Kanno detachment units successfully completed a landing by moving four miles south, before proceeding to Laoag where IJA soldiers took the town and airfield. Homma also wanted to take apart of southeastern Luzon. From the Palau Islands the 16th Division, commanded by Major General Naoki Kimura, sent 2 500 men to take Legaspi. The invasion fleet met no resistance and Kimura Detachment disembarked on 12th December, taking the city with its airfield and a major railroad junction.

Advance Japanese landings

MacArthur’s air situation was precarious. With Japanese in Legaspi and attacks on Davao, the newly constructed base at Del Monte was in danger. Main bomber base at Clark was heavily damaged, and B-17 operations from Del Monte placed significant strain on the maintenance crews, limited facilities, fuel, ordnance, and spare parts. Between increased difficulty of keeping aircraft operational and the Japanese aircraft now being in range, Brereton requested permission to remove all B-17s from Del Monte to Batchelor Field near Darwin, Australia. Flyable B-17s relocated there by 17th December, and Navy’s remaining ten PBY-4s also left the Philippines for Borneo. Only P-40s were left to support the Army, but they too would be crippled by attrition as well as lack of spare parts and fuel.

The Japanese then turned south. IJA’s 16th Army helped Homma to take Davao in southern Mindanao. Davao’s airfield provided a base to expand further south, and Jolo Island in the Sulu Sea could then be taken to support attacks on Borneo. The Sakaguchi Detachment from the IJA’s 56th Division’s 146th Infantry Regiment came ashore at 0400hrs on 20 December, a total Japanese strength of about 5,000 soldiers. Elements of the PA’s 101st Division held Davao, but some units withdrew soon after the Japanese landed on Luzon. By the afternoon, the IJA had taken Davao and Japanese airfield construction crews prepared a seaplane base and avaited the arrival of IJNAF aircraft. Zeros from Davao now had the range to attack targets in southern Luzon, and the Philippines were now isolated.

Early in the campaign, MacArthur’s staff had correctly identified the Aparri and Vigan landings as secondary attacks to acquire airfields. This meant that main landings were only forthcoming. General Wainwright, defending northern Luzon, had adequate number of troops but those were undertrained and underequipped. He had no armored forces, artillery, antitank weapons, and only insufficient air support. There were only a few aircraft left to FEAF, and no reinforcements were forthcoming: with the Pacific Fleet in tatters, Washington had to organize a defense for Hawaii, Alaska, the Panama Canal, and the rest of the United States. While a convoy escorted by a carrier might have been able to breakt through to Philippines, US Navy could not afford a loss of a carrier on such a mission. Neither Chinese nor Soviets were in position to help, and US had to concentrate resources on Europe.

MacArthur did what he could. Lingayen Gulf was identified as the most likely landing site, as it offered a direct route to Manilla. IJA landings at Vigan, Aparri, and Legaspi made MacArthur’s strategy of attacking any invading Japanese forces at the beaches moot, and aim of defending entirety of Luzon was abandoned in favor of defending the area south of San Ferdinando on the coast. Wainwright’s North Luzon force sent the 11th Division and the PS 26th Cavalry to defend the Lingayen Gulf area near San Fernando. A regiment from the 71st Division moved from Mindanao, and Wainwright assigned it to stop the Kanno and Tanaka Detachments moving south to link up with any future invasion force. PA units were to hold the areas where coastal Route 3 and interior Route 5 passed through mountainous area north of San Fernando. The Philippine Division served as the strategic reserve along with the tank reinforcements. Wainwright could call on the 21st Division to hold the area near Lingayen and 31st Division north of Subic Bay. Wainwright however lacked organic tank and armored car presence in his units. While MacArthur did make available the two National Guard tank battalions of 108 M3 Stuart light tanks and M3 half-tracks with M1897 75mm guns which could destroy Japanese tanks, these were not placed directly under Wainwright’s control. But MacArthur relied on PA divisions to stop the Japanese forces, counting that their motivation and morale will make them effective despite the lack of training and equipment.

Japanese landing at Lingayen Gulf

Landing at Lingayen saw almost 45 000 men and 90 tanks land there. Landing was carried on 22nd December with 76 Army and 9 Navy transports. Seven US submarines arrived to the gulf, but only S-38 managed to sink a ship, torpedoing a transport Hayo Maru at 7:59. The Seal, patrolling the area south of Vigan, sank the 856-ton ship Hayataka Maru. But such successes were rare, as the nearly worthless Mark 14 torpedo made US submarines almost useless. Only those two ships were sunk, despite 66 torpedoes having been launched. IJA landing forces at Lingayen Gulf landed largely unopposed, and sporadic resistance by Filipino Army units was brushed aside. US aircraft – Air Force B-17s and P-40s as well as Navy PBYs – tried to slow the Japanese, but this had no effect. The Japanese needed to consolidate the beachheads, defeat any USAFFE defenses, move rapidly to seize several coastal cities, and start the drive southeast towards Manila. To do any of this, they had to break through the American forces. But between questionable PA units, and limited quantity of artillery, air power and naval units, MacArthur held that the only way of stopping the Japanese was through reinforcements.

Filipino troops attempted to stop the Japanese Army at Bauang beaches, but lack of artillery and armor meant that they were quickly overwhelmed and forced to withdraw through Baguio with Japanese forces hot on their tail. The other landings occured without incident, and Japanese forces moved south on Route 3 towards Damortis. Unless stopped, the Japanese would rout the North Luzon Force. 26th Cavalry was ordered to defend Damortis, but strong Japanese attack forced it to retreat. Wainwright needed additional mobility to resist the Japanese, and Company C, 192nd Tank Battalion, moved to engage the enemy near Agoo. Fuel shortages meant that only a five-tank platoon could be sent. One tank was set on fire by IJA Type 95 light tank, and remaining four M3s moved south towards Rosario where they were destroyed by IJAAF bombers.

By night, the Japanese pushed the Americans and the Filipinos out of the Lingayen Gulf area. One of few units not to break ranks against the Japanese was the 26th Cavalry, which held at Binalonan on December 24th, allowing other PA units to move south. Philippine Scout cavalry held until the afternoon when they abandoned it to Homma’s forces. Despite being reduced to 450 men from original 842, 26th Cavalry along with remnants of 192th Tank Battalion attempted to delay the Japanese in Rosario, but that was a failure. Japanese road to Manilla appeared open. Worse, between 22nd and 28th December, Homma managed to land 43,110 men in the Philippines at Lingayen.

Lingayen Gulf landings

Japanese advanced quickly, pushing Filipino forces out of Pozorrubio. IJA’s 48th Division could only be delayed by the Agno River, and MacArthur was forced to implement WPO-3. Wainwright requested approval to create a defensive position behind the Agno, the first of five such lines whose aim was to slow down the Japanese advance while defences of Bataan peninsula were being prepared. Out of five lines, first four were merely intended to slow down the Japanese advance and enforce friction. This would buy time to prepare heavier defences on the D-5 line, which in turn would be held long enough for the South Luzon Force and units near Manila to retreat into Bataan. Yet MacArthur had failed to prepare Bataan for a prolonged siege. Stockpiles needed to be built quickly.

During December 24th, 40 transport ships landed 7 000 men of the 16th Division in the Lamon Bay. Other places were also hit, including the Davao Bay in the far south of the Philippines. Landings were carried out smoothly. US forces in the islands were poorly equipped, lacking in artillery, and widely dispersed. On the opposite side, Japanese landings were well organized. At every point it was clear who was in command. Basic principle of the Japanese command was that the admiral would command initial landings. Once the ranking Army officer declared he can hold the beachhead, he took command over ground campaign while Navy took resposibility of securing lines of communication with the landed forces. Should the landings fail or beachhead had to be abandoned, naval commander would take overall command and direct the evacuation.

Lamon Bay landings

Landings were largely unopposed and carried out without any major issues. Lamon Bay defenders lacked artillery and direct-fire support weapons necessary to stem the Japanese. On the public release of the shift to WPO-3, Brigadier General Albert Jones, the new South Luzon Force commander, had contacted his commanders to start pulling out of the Bichol Peninsula. Japanese 16th Division units faced stiff resistence by the dug-in Filipino 1st Regular Division around the Mauban area. After heavy fighting, Filipino troops were pushed back in spite of air support by American P-40 and P-35 fighters. Japanese forces at other landing sites faced little resistance and were able to join up with units from Legaspi that had moved along the Bichol Peninsula.

Japanese 16th Division pressed westward to reach Tayaba Bay and force the 52nd Division out of Route 1, the main road leading to Manila to the northwest. The bulk of the 16th Division planned to move across the Tayabas Mountains, continue on Route 1, pass Cavite, and on to Manila. By Christmas Eve, the 48th Division was only 100 miles from Manilla while the 16th Division was even closer. Victory seemed close, but MacArthur had other ideas. He had his North and South Luzon forces retreat to Bataan – a feat that was more difficult than usually understood, as a single mistake in coordination could mean destruction of either or both forces. The Japanese advanced to Los Banos on December 28, and the following day the 51st Division sent some of its units into Bataan.

Retreat to Bataan

Japanese troops advanced quickly through forests and mountains towards Manilla, and capture of several airfields allowed the Japanese Air Force to provide much better support. But gradually the resistance stiffened, causing delays. Manilla fell on 2nd January 1942., forcing the US Navy to withdraw its submarines. City itself was not damaged, as MacArthur had declared it an open city on 22nd December 1941. MacArthur withdrew his remaining 50 000 soldiers to peninsula of Bataan, whose hilly terrain and dense forrests provided good defensive conditions, preventing significant usage of tanks and aircraft. Both his headquarters and the Philippine government had been moved to Corregidor.

Major problem were supplies. Depots around the Philippines started to remove supplies for movement into Bataan, but hasty retreat meant that many supplies were lost to the advancing Japanese Army. At Cabanatuan, the Americans left 50 million bushels of rice, a five-year supply, to the Japanese. Situation was made worse by the fact that the logistics officers had based their planning on a much smaller number of soldiers than had actually shown up on Bataan Peninsula.

During this, Wainwright had to keep the roads open to Manilla and other areas so as to allow the buildup of supplies and troops into Bataan. Another crucial task was to slow down Homma and 48th Division while other forces prepared positions in Bataan. From December 24 to 31, Wainwright’s PA divisions managed to stall the 48th Division in the Central Luzon plain. The PA had three divisions (11th, 21st, and 91st, plus the weakened 26th Cavalry Regiment) and the American Provisional Tank Group of two M3 tank battalions to cover the retreat. Limited mobile forces – tanks and halftracks armed with 75 mm guns – were used to plug gaps in defenses and to cover retreating units. Many tanks however were lost due to insufficient coordination with PA units. On one occasion, 15 M3 Stuart tanks were lost because the engineers had destroyed bridges over an impassable stream before the tanks could cross it.

In order to break through the heavily fortified Agno line, Japanese commanders concentrated against Carmen and Tayug, defended by 11th Division and 26th Cavalry Regiment, respectively. If the Japanese could drive rapidly down Route 5, then Homma’s forces might entrap the PA divisions before pushing on to Calumpit and capturing the bridges over the Pampanga River. This would prevent any further supplies from reaching Bataan. Another key city was San Fernando in central Luzon. This was located near an important road junction between Route 3 and Route 7, the main road to Bataan. On 26th December American officials declared Manilla an open city, with MacArthur pulling all of his units out of the city by 31st of December. This meant that Homma would need to divert some of his forces to occupy Manilla while at the same time preparing to advance against Bataan. Homma’s 48th Division also had to capture bridges to stop supplies from entering Bataan.

Despite resistance by 91st and 71st Divisions, Japanese troops reached the outskirts of Baliuag on the last day of December and threatened to cut off access for the South Luzon Force and Manila to Bataan. While 71st Division put up resistance, it was prematurely ordered to leave Baliuag. This forced Jones to send two tank platoons and six halftracks against the Japanese, buying time for PA and other units to get across Pampanga River. M3 tanks inflicted eight Japanese losses with none in return.

By New Years Day Jones had pulled out his South Luzon Force, and Wainwright ordered the bridges destroyed at 6:15. The North Luzon Force and other units were now holding the area near San Fernando, but were forced to withdraw after destroying the bridges. Japanese units had followed the Filipinos south, taking Clark Field while the PA divisions established a new defensive line south of San Fernando. By 2nd January, despite the destroyed bridges, IJA units had crossed the Pampanga River at Calumpit and moved north along Route 3.

From New Year’s Day until January 6, the 11th and 21st Divisions withdrew towards Layac where they formed a new defensive line. But constant Japanese attacks slowly forced the defenders back, despite high casualties incurred at the hands of American tanks and the 26th Cavalry Regiment. The 26th Cavalry, American tanks, and the remnants of the 11th and 21st Divisions stood between Homma and the rest of Wainwright and Parker’s forces across an 8-mile neck behind the Cuto River. The remainder of the North Luzon Force had withdrawn into Bataan. The 26th Cavalry also withdrew for Bataan in early morning of 7th January.

In total, MacArthur had lost 13 000 troops since the landings, while Japanese casualties numbered about 2 000. Many PA units had suffered heavy desertion, and the best that US and PA units were capable of pulling off was a fighting retreat.

The Defense of Bataan

Bataan was a good defensive position. The peninsula only had two main north–south roads on each coast and one road that bisected it. The eastern coast had a wider maneuver area, at least near the base of the peninsula. About 25 miles long and 15 miles wide, Bataan was dominated by several mountain ranges. Corregidor was located off the southern coast of the peninsula. Terrain was mostly jungle, so if the defenders could entrench themselves, the Japanese might not capture it easily.

However, there were issues. Supplies of food, medicine, weapons and ammunition were very limited as the defense was prepared on the assumption that the Pacific Fleet would be able to relieve the defenders in six months. Starting with 5th January 1942., MacArthur put all Army personnel on half rations. Army officers had planned on feeding and supporting about 43,000 military personnel. Instead, the American and Filipino force now numbered over 80,000 soldiers and 26,000 civilians.

MacArthur split his forces in Bataan into two corps. Wainwright was to command I Philippine Corps of 22,500 personnel covering the western part of Bataan. Parker led the II Philippine Corps that covered the eastern half of Bataan with 25,000 soldiers. Each Corps had four divisions. These corps covered three main fighting positions, with Wainwright’s I Corps covering the Mauban Line, and II Corps covering the Abucay Line. Mount Natib in the center of the American line was believed to be impossible to traverse and so was not defended at all. Rear battle position that stretched from Bagac to Orion across the peninsula, about 8 miles south of the main battle position, based around Mount Samat.

MacArthur aimed to perform a defense in depth, taking advantage of the rugged terrain to delay the Japanese until the reinforcements could arrive. Attack on the east coast of Bataan was judged as most probable, as the only usable road (East Road or Route 110) connected with Route 7 and the Japanese forces now north of Bataan. It was also open, while western coast was covered with jungle.

Battle of Bataan

After pushing American and Filipino forces out of Luzon, IJA stopped to reorganize and prepare for the final push into Bataan. 65th Brigade with three infantry regiments (containing organic artillery support) and 7th Tank Regiment pushed south to break the II Philippine Corps’ position. Facing them was the 51st Division, while the 41st Division held the center of the line.

On 9th January Nara started moving against the Abucay Line. Two Japanese regimental combat teams advanced across the neck of the Bataan peninsula in spite of defensive artillery fire. At the same time, the Japanese 122nd Infantry Regiment moved west, capturing Fort Wint and then Olongapo. The main attack against the Abucay Line started the following day, but initial attacks failed to achieve much. Some headway was made of 12th of January, but this territory was soon lost as Parker sent in more reserves to area around Matabang. Limited Japanese advance did occur against the middle and western sectors of the Abucay Line. These attacks broke the battered 51st Division deployed in the western sector, threatening to roll up the entire defensive line as Parker had no mobile reserve available.

MacArthur thus had to fill in the breach in order to prevent a total collapse. Japanese columns were also advancing into I Corps area. On January 16th, Japanese 122nd Infantry Regiment approached Moron where they were engaged by the 26th Cavalry Regiment in what was the last known horse-mounted charge of World War II. Japanese troops were scattered as they tried to cross the Batalan River, but on the 17th Wainwright’s troops were forced to retreat from Moron.

The Abucay Line was still MacArthur’s main concern. Thus he ordered the Philippine Division and other reserves to plug the gap left by the 51st Division. American 31st Infantry Regiment and 45th Infantry Regiment failed to prevent Japanese 9th Infantry Regiment from penetrating the Abucay Line along the Abo Abo River Valley. Nara’s and Parker’s forces collided in a relative stalemate, but IJA used the terrain which Wainwright had deemed “impassable” to advance against the defensive positions. Kimura broke through and cut off the Mauban Line, and by 21st January American forces there were in full retreat. Nara’s forces started their offensive against the Abucay Line on 22nd January, pushing Parker’s forces back. MacArthur decided to pull all remaining units out of main battle positions starting on the evening of 23rd January. By 26th January, all I and II Corps units were in new defensive positions at Bagac-Orion Line, which was continuous and thus offered MacArthur more of a chance to stop the Japanese advance.

The Battle for the Points

Japanese had eventually succeeded in punching through the Mauban Line, and the next target was the city and the naval base of Mariveles. In order to avoid difficult terrain and cut off the defenders, Hamma planned to have 1st and 2nd Battalions of 20th Infantry Regiment carry out the landings. Japanese soldiers would land in small, isolated inlets, fight their way over the sharp cliffs, and then proceed inland. These units would then operate independently until they could be reinforced.

Landings however went awry. Rough seas, poor weather, American PT boats and poor quality maps meant that heavy losses were suffered even before the troops had landed, and many missed their landing points by miles. Luckily for the Japanese, the only American and Filipino forces defending the area were a mixed force of FEAF airmen, Marines, sailors, and Philippine Constabulary, most of whom had little to no infantry training. Thus, when they tried to dislodge the Japanese forces moving inland from Longoskawayan point, the best they could do was to push the invaders back, but could not dislodge them despite receiving significant artillery support. MacArthur was thus forced to send in trained infantry.

By this time, 600 IJA troops had consolidated at Quinauan Point despite the efforts of airmen from 34th Pursuit Squadron and a battalion of the 1st Philippine Constabulary to push them back. No tanks were available either, and so the Japanese could establish the defensive positions. Reinforcements the American-Filipino forces did get amounted to two British Bren gun carriers and reinforcements from the 21st Pursuit Squadron, more Constabulary forces, and elements of the 71st Division.

Situation remained in balance for several days as both sides tried to reinforce their positions. Renewed Japanese landings again arrived at wrong points, while Wainwright sent further units and MacArthur released some M3 tanks. MacArthur also made repeated calls to Washington for reinforcements: he had some 90 000 troops on Bataan, Corregidor, and the outlaying coastal defense positions in Manila Bay. But these were weakened by hunger and dysentery, and MacArthur had only seven P-40s left on Bataan. Reinforcements of Filipino scouts and tanks allowed the Americans to destroy the Japanese position on Longoskawayan Point by 29th January and on Quinauan Point by 13th February. This thwarted the invasion and cost Homma two battalions.

Homma Retreats North

During the Battle of the Points, Homma tried to penetrate the Bagac-Orion Line. Nara managed to break II Corps defences on the line in two places on 28th January, but the advance bogged down. MacArthur’s counterattack likewise failed to defeat the Japanese, leaving two sides in a stalemate. By 8th February, Homma realized he had to withdraw and thus disengaged all along the Bagac-Orion Line and moved north before requesting reinforcements from the HQ.

Homma had failed to conquer the Philippines on schedule, and his forces needed time to recuperate and reorganize. The 14th Army had sustained 2,700 killed and 4,000 wounded from early January to March 1 in Luzon, while as many as 12,000 Japanese soldiers suffered from disease and sickness. As operations had also began against Singapore, reinforcements were not available in the theater. 4th Division, whose deployment had been approved on 10th February, needed time to move from Shangai to Bataan. Siege artillery was also transferred from Malaya and Hong Kong, as were additional IJAAF and IJNAF bomber units. Operations could only take place in early April, while American-Filipino forces were weakening due to lack of food and medicine, and diseases taking their toll.

Situation for the US forces was bad. Insufficient preparation meant that troops were quickly reduced to eating horses and monkeys, and almost half were disabled by malaria, dysentery and other diseases. There was also a lack of medicine, and weak medical service in general meant that more soldiers died from diseases than in combat. Homma thus only stood to gain from a pause in fighting.

MacArthur Leaves

MacArthur planned and directed operations from the Corregidor. The island was the main defensive position of the Manilla Bay, with Fort Mills located on the island with 14 batteries to protect Manilla Bay and Cavite. Yet island had little defense against air strikes. With an assigned strength of 6,000 soldiers, the island was self-contained. It had a power plant, water desalination facility, a railroad, airfield, and housing. A key structure was the Malinta Tunnel, completed in 1932, which served as MacArthur’s main headquarters during the campaign.

Japanese blockade meant that the possibility of reinforcements was remote at best. Only three out of six transports from Australia reached an island of Cebu, and troops that tried to reach Corregidor from there by using inter-island steamers were mostly sunk or captured. Only possibility of resupply were aircraft and submarines, but these did not provide what was needed.

Washington realized that the fight was lost. Philippines could not be defended. But his dogged defense has earned MacArthur status of a hero, and his capture or death would be devastating for the morale back home. Because of this, on 22nd February Roosevelt ordered MacArthur to leave the Philippines and take command of forces in Australia and the Southwest Pacific Area. MacArthur however only left on 12th March, departing for Mindanao on four torpedo boats along with his family and select staff members, and flying by B-17 to Australia. MacArthur made Wainwright commander of all Luzon forces, but kept the overall command for himself. MacArthur reached Australia on 17th of March, and in a speech in Adelaide he made a personal commitment to the Filipinos, declaring that “I shall return”. Roosevelt and Marshal arranged for Wainwright’s promotion to lieutenant general and made him a new commander of US forces in the Philippines.

The Fall of Bataan and Bataan Death March

With MacArthur gone, no reinforcements, mounting casualties, and dwindling supplies, the morale of the American-Filipino defenders began to suffer. By 24th March, Homma’s reinforcements were having an appreciable effect. IJA artillery battered the Bataan defenders, while IJAAF and IJNAF bombers struck targets on the peninsula. Manila Bay fortifications were also being pounded by artillery.

Homma decided for IJA’s 4th Division, with 11 000 men, to make the main effort to penetrate the lines near Mount Samat. 16th Division meanwhile would mount diversionary attacks. While Wainwright had 79 500 soldiers, most were sick or wounded. Japanese forces launched an attack against the Bagac–Orion Line at 9:00 on 3rd April with a massive artillery barrage. This was followed by artillery and air attacks against the 41st Division in the center of the line near Mount Samat. In one day, the 41st Division was badly mauled and Japanese had slipped past and were advancing south against minimal opposition.

Over the next few days, the Japanese pushed back PA units in the Mount Samat area. US and PA units were now in full retreat, and boats were arriving to evacuate them to Corregidor. Homma decided to move his 4th Division through the foothills to capture Mariveles while the 16th Division continued to harass the enemy. The plan was executed on 9th April, and the II Corps disintegrated. By 12:30 of 10th of April, King had surrendered and Bataan had fallen.

US troops surrender on 9th April

With the fall of Bataan, thousands of wounded and malnourished prisoners fell into Homma’s hands. Homma himself had planned for 25 000 prisoners, yet the Japanese took 78 000. Lack of transportation meant that Homma had to force them to walk 65 miles from Bataan to Camp O’Donnel in central Luzon. Japanese soldiers did not treat prisoners well. Under the Japanese Bushido warrior code, surrender was abhorrent since a soldier’s duty was to fight to the death. If a soldier gave up, then he forfeited the right to humane treatment – and the Americans and Filipinos had surrendered en masse. Prisoners were given no food, water or medical aid, and IJA soldiers beat or killed any stragglers. About 2 330 Americans and 10 000 Filipinos died during the march, and many more in the labor camps in China, Formosa and Japan.

Fall of Corregidor

In the end, US forces were forced to withdraw to the fortified island of Corregidor. And with fall of Bataan, Corregidor was next in time. The American-Filipino forces defending the island were isolated from any help, but Homma still required time to prepare for an amphibious operation to take the island. In order to break down the defenders, the Japanese intensified air and artillery bombardments which left facilities on Corregidor damaged, making it difficult to prepare for defense.

Corregidor in 1941

Some 13 000 defenders had withdrawn into the fortress called “the Cave”. Located underneath the Malinta hill, the main fort consisted of a long tunnel from which many side tunnels spread into the mountain. These contained living rooms, storerooms, magazines, hospitals and other necessities. External storage areas had been emptied, and only crews of artillery and other defensive positions were outside the shelter of the tunnels. Between the original garrison and the survivors of Bataan, some 4 000 men were protecting the beaches. Defenders however were starving on half-rations.

Heavy pre-invasion artillery and air attacks on Corregidor began on 29th April. Japanese planned two landings. First landing, on 5th May, would take place on the north coast at Infantry Point. The 4th Division’s 61th Infantry Regiment, with tanks, would take Malinta Hill and its tunnel. The next day, the 37th Infantry Regiment and other reinforcements would come ashore between Morrison and Battery Points at 2330hrs to complete the assault.

By 4th May, Japanese were firing 16 000 projectiles over 24 hours. Large cannons on Corregidor had been destroyed, as were coastal defences. Bombardment had caused some 600 casualties among defenders, but their ability to fight back had been severely hampered. On 5th May, Japanese infantry landed onto the island. Heavy fire by two 75 mm guns had caused significant casualties, with Homma reportedly losing two-thirds of his force and 31 vessel. But this was not enough to stop the Japanese, and they advanced despite the heavy losses, capturing the Denver Battery.

A provisional battalion of 500 soldiers, sailors and Marines launched a counterattack at 6:00, but it was unsuccessful and the defenders had to fall back towards the Malinta tunnel. IJA soldiers had infiltrated the American defenses and Homma’s men, along with three tanks, had killed about 600 to 800 defenders and wounded 1,000 more. Having no way to stop the Japanese tanks and fearing that the enemy may fire onto wounded men in the tunnels, General Wainwright ordered a surrender at 10:00. Homma’s men took the Malinta tunnel and by 11:00 all hostilities had ceased on Corregidor. Wainwright ordered a ceasefire to prevent a slaughter and sought out the Japanese to surrender.

Southern Philippines Operations

While Homma struggled to take Bataan, he also carried out operations in areas south of Luzon. With his limited forces, Homma had to request reinforcements to take the rest of the Philippines, especially Mindanao. The IGHQ sent elements of the 18th Division, 5th Division (from Malaya), and other units to the 14th Army to conclude the Philippines campaign.

The first move in the south was aimed at Visayan Islands between Mindanao and Luzon. MacArthur had assigned five PA divisions to the area, but then had two divisions redeployed to help defend Luzon. Remaining forces were thinly spread in static positions, with insufficient artillery, as well as serious lack of trained personnel and even the basic equipment such as steel helmets. In total, there were 20 000 men in the Visayan Area, under command of Brigadier General Bradford Chynoweth.

The most important IJA targets were the Cebu and Panay Islands. Poorly trained and equipped troops of the Philippine Army proved unable to hold the defences. Despite the defenders’ numerical advantage of 6 500 men on the Cebu Island against Japanese force of 4 852, the main city of Cebu fell in a day. The island itself followed shortly after, when Japanese troops took the crucial crossroads in Cantabaco. On 16th of April, Homma sent 4 160 men, the Kawamura Detachment, to take Panay which was defended by the 7 000 strong 61st Division. Defenders attempted to delay the Japanese forces through demolition of bridges and roads, but the Kawamura Detachment soon took control of all cities and roads. By 20th of April, IJA controlled all of Panay.

Next was Mindanao. While IJA forces had taken Davao and Digos earlier, they had not expanded their beachhead. Homma decided to launch a two-pronged amphibious invasion by Kawamura and Kawaguchi Detachments. From Digos, Japanese forces would drive north to link up with the invading forces. The Kawaguchi Detachment landed in the West near Parang on 29th April with 4852 men despite the opposition by the 101st and parts of 1st Regular Divisions. The Kawamura Detachment landed near Cagayan and Togoloan on May 3. Japanese forces pushed inland, and Sharp, commander of Mindanao, ordered a general retrat to the center of the island. But by 9th May, the IJA had routed Sharp’s forces and conquered the island.

Final Surrender

Homma had believed that all US forces had surrendered upon Bataan’s fall, but instead had to fight against Corregidor and southern Philippines. Just before Corregidor’s fall, Wainwright had released his command of the Mindanao-Visayan forces to Sharp on 6th of May. Homma however would not accept Wainwright’s surrender unless all American-Filipino forces gave up. Fearing retaliation against his vulnerable men on Corregidor, Wainwright ordered all American and Filipino forces to surrender via a radio broadcast from Manila on May 7. While some troops disregarded the order and continued with guerilla resistance, any organized resistance had ceased by 9th June.

Surrender of American troops at Corregidor, Philippine Islands

The Philippines had provided the US with many valuable lessons that would be implemented later. MacArthur’s strategy of trying to defend entirety of the islands was a clear mistake. It allowed his forces to be defeated piecemeal, and also prevented sufficient supplies from being built up in the Bataan peninsula. But even had MacArthur made no mistakes, the islands were indefensible. Yet Japanese also made mistakes, primarily in identifying the centre of gravity of the US forces. Ignoring the Sun Tzu’s maxim, Homma expected that fall of Manilla would force capitulation despite the presence of a major army in Bataan.

3 thoughts on “Pacific War 7 – Invasion of Philippines

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