ASSAULT TACTICS EMPLOYED
AS EXEMPLIFIED BY
THE BATTLE OF MANILA

 

A REPORT BY XIV CORPS

as formally delivered by H. O. EATON, JR.,

Colonel,  G. S. C.,

A. C. of S., G-2. 


___________________________________

I. GENERAL PLAN

1. Factors precluding early planning

It is recognized that proper plans for the capture of a built -up area call for careful estimates of the situation based on detailed study of the city itself, and of enemy dispositions within and without it. The plans should comprise initial seizure within the city of area which gives advantage to the attacker in observation, fields of fire, means of communication, and which works to the disadvantage of the enemy in reducing his combat effectiveness and preventing or hindering his escape. Afterwards a general advance through the built-up area should be made. Formulating such plans for the capture of Manila was greatly influenced by several factors attributable not only to the enemy defense but also to special circumstances.

Initially, the plan of the XIV Corps in attacking Manila was complicated by several factors. Although to the U. S. Forces marching South from Lingayen Gulf the capture of the port of Manila at an early date was very necessary, in the early stages of the battle virtually all effort was directed to liberating American prisoners of war and Allied internees whom the enemy held at Santo Tomas University and at Bilibid Prison in North Manila. Special effort was also made to secure the vital installations of the water system. Advance elements of the XIV Corps came down from the North with great speed and drove rapidly into Manila, liberating the prisoners before the enemy could harm them. This drive resulted, however, not only in freeing the prisoners but also in securing virtually the whole of North Manila.

Another factor which prevented early planning was the difficulty in determining the location of main enemy dispositions within the city, or even if they existed. The Japanese defense of Manila comprised a strongly held core, the Intramuros, with its nearby fortified buildings, and surrounding this core, several isolated fortified localities. Units searched the city thoroughly as they went, yet struck nothing very formidable until reaching the center of the enemy defense. This rendered very difficult properly estimating the situation until major friendly forces were in contact with the bulk of the enemy. 

2. Estimate of the Situation

Before U. S. Forces struck the main line of enemy resistance in Manila there was almost nothing on which to base an estimate. After solid contact was made at the Pasig River, the rigidity of the enemy defenses on the far bank tended to force the plan of action into the elementary expedient of crossing further upstream and attacking the enemy in flank. 

3. Plan for the attack

The XIV Corps, having secured North Manila to the Pasig River with two divisions abreast, the 37th Infantry Division on the right and the 1st Cavalry Division on the left, planned to move the 1st Cavalry Division and two regiments of the 37th Infantry Division Eastward, effect with this force a double crossing of the Pasig River, and attack Westward with divisions abreast against enemy fortifications in the Intramuros area. One regiment of the 37th Infantry Division was to move directly across the Pasig River and attack enemy positions on the South bank. 

4. Conduct of the attack

The 37th Infantry Division (less one regiment) moved eastward through North Manila, crossed the Pasig River and attacked West toward the enemy held Intramuros. The remaining regiment of the 37th Infantry Division held the river line directly across the Pasig from Intramuros. The 1st Cavalry Division, abandoning contact with the 37th Infantry Division, executed a wide wheeling movement inland and swept into Manila from the Southeast. This maneuver actually worked somewhat to the detriment of the overall attack, as it permitted a very strong center of enemy resistance, the Makati Circle area, to survive for days directly between the divisions, a thorn in the side of each. In this respect it is believed that by-passing too many strong isolated Japanese centers of resistance is a mistake, as the number of troops necessary to contain the Japanese will far exceed the number of Japanese contained. When Japanese Forces are deployed in rigid defense, it is considered advisable to destroy all enemy as the attack progresses. When it is advisable to by-pass centers of resistance, such centers of resistance should be reduced immediately, employing available reserves. If sufficient reserves are not immediately available, progress of the attack should be controlled by phase lines until strong points are eliminated.

Nevertheless, elements of the XIV Corps closed in on Central Manila and attacked the Japanese prepared defenses of which Intramuros was the hub. The fighting which resulted in the destruction of these defenses and the final elimination of enemy resist! ance in Manila was in reality that which characterizes the attack of a fortified locality, and for discussion may be divided into three categories, namely normal fighting in city streets, the reduction of strong earthquake proof buildings, and the attack upon the ,Walled City (Intramuros). The fighting did not fall together chronologically into these categories, as several strong enemy-held buildings were contained and by-passed to permit the assault upon Intramuros, and within Intramuros itself normal street fighting was resumed. 

5. Limitations on bombing and artillery fires

As it was desired to capture Manila as intact as possible, and since a large fraction of the civil population was still inside the city when U. S. Forces attacked, bombing of Manila or any part of it was forbidden, and the use of artillery fire against enemy fortifications was greatly restricted. Initially, sections of the city were attacked by Infantry, using small arms. Artillery fire was restricted to counter-battery and to observed fire on known enemy strong points. The casualty rate was alarming and the attack was slowed up to a point where more powerful measures were required. These measures consisted of attaching tanks, tank destroyers, and 4.2" mortars to the infantry, and a greater use of field artillery. However, as the main line of Japanese resistance was reached, it became apparent that destruction of the buildings in the path of advancing troops was essential. Artillery fire was still restricted to known Japanese positions but so many enemy riflemen were interspersed within the positions that artillery area fire immediately in front of the advancing troops became the rule rather than the exception. A general overall program of destruction by artillery fire was never employed. Japanese heavy mortars, 20 and 40mm guns, and even large caliber artillery were found in city buildings. The combination, therefore, of counterbattery (directed from observation posts and by plane spot), together with close-in fires in support of the advancing infantry resulted in almost total destruction of the defended areas.

 

enlarge (large file)

This map of the city proper showing principal street widths, important buildings and installations was used by a member of the Serial that first reached Sto. Tomas Internment capmp on Feb. 3, 1945. It is one of the maps from the Manila Terrain Study Handbook.

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THE INSULAR ICE PLANT

 

 The Insular Ice Plant Building (built 1910)  - A pre-war Manila landmark because of its distinctive chimney stack, the chimney had a whistle which used to sound out the hours. Img via JT

 

 

 

 

 

 

 

 

 

THE GENERAL POST OFFICE

The General Post Office prior to the crossing of the Pasig River.  In accord with normal practice, distances in the Philippines were measured from the General Post Office, so the building was essentially at the heart of the city.

The fight for the General Post Office, conducted simultaneously with that for the City Hall, was especially difficult because of the construction of the building and the nature of the interior defenses. A large, five-story structure of earthquake-proof, heavily reinforced concrete, the Post Office was practically impervious to direct artillery, tank, and tank destroyer fire. The interior was so compartmented by strong partitions that even a 155-mm. shell going directly through a window did relatively little damage inside.
 

 

The Japanese had heavily barricaded all rooms and corridors, had protected their machine gunners and riflemen with fortifications seven feet high and ten sandbags thick, had strung barbed wire throughout, and even had hauled a 105-mm. artillery piece up to the second floor. The building was practically impregnable to anything except prolonged, heavy air and artillery bombardment, and why the Japanese made no greater effort to hold the structure is a mystery, especially since it blocked the northeastern approaches to Intramuros and was connected to the Walled City by a trench and tunnel system. Despite these connections, the original garrison of the Post Office received few reinforcements during the fighting and, manifestly under orders to hold out to the death, was gradually whittled away by American artillery bombardment and infantry assaults.

 

For three days XIV Corps and 37th Division Artillery pounded the Post Office, but each time troops of the 1st Battalion, 145th Infantry, attempted to enter the Japanese drove them out. Finally, on the morning of 22 February, elements of the 1st Battalion gained a secure foothold, entering through a second story window.

 

 

Annex 10 - Ground floor, General Post Office

 

 

Annex 11 - Second floor, General Post Office

 

 

The Japanese who were still alive soon retreated into the large, dark basement, where the 145th Infantry's troops finished off organized resistance on the 23d. Nothing spectacular occurred--the action was just another dirty job of gradually overcoming fanatic resistance, a process with which the infantry of the 37th Division was by now all too thoroughly accustomed.