As tensions continue to rise between the Philippines and China and with US troops poised to return to the archipelago, the military has a need to understand the lessons learned from the last time American soldiers fought in the Philippines. While readers are likely familiar with the fights for Bataan and Corregidor, naval battles at Leyte and Lingayen Gulf, and General Douglas MacArthur’s photographic return, the urban battle for Manila in 1945 is equally as important, if lesser known. This month-long campaign to recapture the Japanese-held “Pearl of the Orient” was the fiercest urban combat of the entire war in the Pacific, and, for students of urban warfare, can provide excellent lessons on war within a dense Indo-Pacific urban stronghold. As populations rise in Southeast Asia’s megacities, the likelihood of an urban battle in the Indo-Pacific grows, making the battle for Manila a relevant case study for urban warfare practitioners.
The Battle of Manila was conducted as part of the larger campaign to recapture the entire Philippines. The city held symbolic importance as the nation’s capital, the center of Japanese occupation authorities, and MacArthur’s former home. With approximately eight hundred thousand residents, Manila was one of the largest population centers encountered by American forces in any theater. Additionally, American civilian and military prisoners were being held at an internment camp within the former Santo Tomas University campus, many of whom had been captured in 1942 after MacArthur’s departure.
At MacArthur’s disposal to recapture the city were the 37th Infantry, 11th Airborne, and 1st Cavalry Divisions, totaling thirty-five thousand troops, with additional support from Filipino guerrillas and air support from the US Army Air Forces’ Far East Air Forces. The defending Japanese fielded a force of roughly 13,500 men of the Imperial Japanese Navy’s (IJN) 31st Naval Special Base Force that had refused orders from the Imperial Japanese Army (IJA) commander to withdraw. These forces were augmented further by roughly 4,500 IJA troops from various units.
IJA General Tomoyuki Yamashita, who commanded all Japanese troops on Luzon, did not want to defend Manila for two reasons. First, he saw its mainly flammable wooden buildings as a death trap for his troops. Second, the large civilian population would require feeding and care, something his logistically starved troops could not do. However, the IJN commander, Admiral Sanji Iwabuchi, saw himself under no obligation to listen to orders given by his rivals in the IJA, and in hopes of regaining his honor, elected to stay with his forces and fight to the death while Yamashita and the majority of the Japanese retired from the city.
The defenders’ goals were to inflict maximum casualties on the US forces, delay the use of the port of Manila by the US Navy, and make the city unusable for military, civilian, or political purposes. The Japanese began development of an extensive defensive network centered on the Intramuros district of the city. This district, with its high walls and moats, contained a number of large stone and concrete government buildings around its edge which were occupied by the IJN. Since Manila lies in an earthquake zone, many of the buildings were already reinforced to prevent collapse, aiding the defenders. These buildings were reinforced further with sandbags on roofs, by bricking up doors and windows, and with murder holes cut into walls to allow fire along avenues of approach. These buildings were often then connected by subterranean tunnels or through the existing sewer system, which was also used to store supplies. These defensive strongpoints negated American advantages in firepower and air support.
Along the southern edge of the city, the Japanese built a defensive line, running east to west, called the Genko Line. The Genko Line provided defense in depth against an attack from the south and consisted of minefields, pillboxes, and converted antiaircraft and naval guns, creating an almost impenetrable network of overlapping fires. Further preparations included creating an airstrip along Dewey Boulevard from cut down trees, as well as the emplacement of more than 350 antiaircraft and dual-purpose guns across the city, some of which came from wrecked ships in Manila Bay.
Scheme of Maneuver
On February 3, 1945, the 1st Cavalry Division and the 37th Infantry Division advanced on Manila from the north, while the 11th Airborne Division advanced from the south toward the Genko Line, effectively isolating the city from the rest of the Japanese forces on Luzon. The US forces planned to seize key civilian centers of gravity while bypassing the major Japanese strongpoint at Intramuros. Japanese defenders hoped to stop the 11th Airborne Division’s advance northward along the east-west barrier of the Genko Line, while conducting a defense in depth against the much American larger force attacking from the north, drawing the attackers into the city and inflicting maximum damage.
The northern American force quickly captured the northern outskirts of Manila but was halted when Japanese defenders blew a key bridge over the Pasig River. The 1st Cavalry Division diverted east to capture the vital Novaliches Dam, San Juan Reservoir, and Balara Water Filters, which provided fresh water to the city and its population; meanwhile the 37th Infantry Division began conducting riverine crossings of the Pasig under heavy fire to secure a foothold on the far bank and capture Manila’s main power plant on Provisor Island. As the 37th Infantry Division began clearing Japanese strongpoints on the southern side of the Pasig, the 1st Cavalry Division moved west to secure the port.
To the south, the 11th Airborne Division successfully breached the Genko Line, forcing the Japanese to retreat further into the city. The 1st Cavalry and 37th Infantry Divisions chose to isolate and bypass the Intramuros district and pressed south in order to link up with the 11th Airborne Division. Once Intramuros was successfully isolated, US forces stormed it using a combination of riverine infantry assaults and armored spearheads through two of the gates into the walled fortress. After the clearance of the last strongpoints in and around Intramuros, little Japanese resistance remained, and after mopping up, the Americans declared the city secure on March 4, 1945.
The Japanese, despite their extensive preparation of the battlefield, were almost doomed to fail as soon as the Americans had encircled the city. Once isolated, as seen in other urban fights, the defenders lost the ability to resupply, and were consigned to either starving or being rooted out one by one by the advancing Americans. With a force of nearly twenty thousand men, the Japanese should have been able to mount a counterattack and break out from the encirclement of only thirty-five thousand Americans in three divisions, but the lack of coordinated Japanese counterattacks and overall static defensive strategy allowed the Americans to effectively trap the defenders and clear the city.
Understanding the civilian environment of the city, and its relationship to the physical infrastructure, was an important factor in the planning and execution of the American liberation of Manila. American planners understood that much of what would determine success in the Manila campaign would be the ability to capture key political and infrastructure nodes, allowing the city to function as a seat of government after its liberation. The Japanese, likewise, understood this and made deliberate preparations to deny Manila as a city to the Americans.
Within Manila, the power plant, water treatment plant, port, Novaliches Dam, and San Juan Reservoir were seen by both as critical centers of gravity. Accordingly, the Japanese planned to destroy these as part of their scorched-earth campaign, while American forces sought to secure them intact. In the initial stages of the battle, the 1st Cavalry Division quickly secured the water treatment and storage areas east of Manila, which provided potable water to the entire city. Likewise, Provisor Island, which housed the power plant, could have easily been isolated and bypassed by US troops, but needed to be seized to maintain the city’s electrical power.
For contemporary planners, it is critical to understand and analyze a city not simply through physical terrain analysis, but through the lens of civilian considerations and the operational environment variables, particularly infrastructure’s role in supporting civilians. Understanding how the civilian environment overlaps and interconnects with the physical environment is critical in developing schemes of maneuver. The loss of critical infrastructure could kill a city as quickly as an enemy force. Soldiers defending a city, for example, may have to defend a critical water treatment plant or a dam to prevent the death or displacement of vast portions of the city’s population.
Civilians on the Battlefield
The IJN plan to spoil the American victory and to further ensure the destruction of Manila as a functioning city was to include not only destroying critical infrastructure but also the deliberate murder of thousands of civilians. In scenes reminiscent of Nanking, thousands of innocent men, women, and children were shot, stabbed, beheaded, skinned alive, raped, and mutilated by Japanese forces in what became known as the Manila Massacre. Thousands more were driven from their homes and left without food, shelter, and access to medical care. Response to these mass atrocities committed within Manila became an additional mission of US Army forces across Luzon. US troops were tasked with caring for displaced persons. The care of civilians displaced from the battlefield became a major concurrent mission during and after the battle.
Urban battles do not occur in sterile environments. Within Manila, more than one hundred thousand civilians were killed either deliberately by the Japanese or caught in the crossfire. Current US forces need to be prepared to address the presence of civilians on the battlefield. As cities, particularly in the Indo-Pacific region, continue to grow in population, US forces will have to divert more attention to caring for and handling civilians on the battlefield. As General Charles C. Krulak described in his depiction of the “three-block war,” US forces must be prepared to conduct stability operations in close coordination with and proximity to ongoing combat operations. Both maneuver and support units must be ready to respond to mass atrocities and provide basic assistance to civilians, and to do so while under the scrutiny of social media. At higher echelons, this concept of a three-block war must be understood holistically in order to allow for proper coordination with nonmilitary humanitarian organizations, and for supplying adequate logistical capabilities and personnel to conduct these humanitarian operations.
Concrete and Stone
The high variability of Manila’s physical terrain that American forces encountered provides further lessons for modern observers. The city was composed of everything from small, wooden houses to massive, earthquake-resistant government buildings, such as the Manila Post Office that withstood days of direct artillery and tank fire. An entire squadron of the 1st Cavalry Division was forced to clear the Rizal baseball stadium that was being used as a Japanese ammunition dump, eventually driving tanks across the field to engage defenders fortified within the dugouts. The thick, Spanish-era forts and walls of the Intramuros further provided a unique challenge to the Americans, who had to contend with assaulting structures and reducing barricades that had been made to withstand sixteenth-century siege warfare.
Today, cities throughout Asia are also full of a diverse blend of architecture dating from dozens of distinct time periods. In Bangkok during the 2010 riots, the Thai military used armored personnel carriers and thousands of troops to clear a shopping mall full of protestors, resulting in massive fires throughout the area. In the Battle of Hue in 1968, North Vietnamese forces used the ancient Hue Citadel as a fortress, stymying American and South Vietnamese forces. More recently in Ukraine, the Ukrainian defenders of Mariupol turned the Azovstal steel factory into a nearly impenetrable fortress, defying the Russian invaders for months. US forces in the future could find themselves operating in a dense urban area with a wide variety of physical terrain including the sprawling shopping malls and wide boulevards of Singapore or Taipei, endless high-rise apartment buildings like those of Beijing and Seoul, and shantytowns and slums like those in Dhaka or Mumbai.
The Japanese defense of Manila likewise provides valuable tactical lessons. The defenders conducted extensive terrain analysis and engagement area development, turning intersections into kill zones and buildings into veritable fortresses. The Genko Line demonstrated successful defensive planning, as the Japanese integrated obstacles into their defenses to disrupt and canalize enemy movement into carefully prepared engagement areas and kill zones, covered by their pillboxes and converted artillery pieces.
For modern leaders, Manila provides a lesson on conducting effective terrain analysis and engagement area development. The urban environment can provide advantages to the prepared defender while canalizing and minimizing the maneuver and fire capabilities of the offense. Being able to analyze key terrain and avenues of approach, then planning engagement areas around them, is critical in the extremely complex terrain of urban areas. Simply emplacing forces on line for continuity or attempting to defend everywhere at once will see defenders quickly overrun, isolated, or bypassed.
Combined Arms Warfare
The American assault in Manila further proved the effectiveness of combined arms urban warfare. As in other urban battles, such as at Aachen, American tanks and artillery quickly became direct fire breaching assets that would punch holes into the thick walls of the Intramuros and government buildings, especially after MacArthur limited artillery fires in order to spare the city unnecessary destruction. Infantrymen also developed new clearing tactics, often using flamethrowers and bazookas to clear rooms and buildings. At the post office, infantry soldiers further innovated by bypassing the Japanese defenders on the heavily fortified ground floor and breaching the structure through a window on the second floor, then fighting their way downstairs.
Recent combat in Ukraine and changes to force structure have called into question the effectiveness of armored urban warfare. In Manila, the combination of armor, infantry, engineers, and artillery at the tactical level provided a lethal combination that allowed American forces to aggressively breach and clear structures. American forces demonstrated that armor plays a role in an urban fight if properly supported by infantry.
After the conclusion of fighting, a report from the 112th Medical Battalion, part of the 37th Infantry Division, described Manila south of the Pasig River as “a fantasia of death and destruction.” The battle for the Pearl of the Orient demonstrated the powerful effects of combined arms maneuver, the criticality of defensive preparation of the battlespace, and the humanitarian consequences of urban conflict. As the US military continues to reprioritize the Indo-Pacific region, and reinvests in the strategically important Philippines, it is critical to study and learn from battles previously fought on that same ground.
Benjamin Phocas is a cadet at the United States Military Academy, where he is in the Defense and Strategic Studies program. He is an intern for the National Center for Urban Operations.
The views expressed are those of the author and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.
Image credit: Government of the Philippines