6. Assault on Intramuros

The assault upon Intramuros was unique. A thick masonry wall averaging 20 feet in thickness surrounded Intramuros. Extensive gun emplacements and tunnels in the wall itself had been constructed by the Japanese. Maximum use was made of the apparently impregnable cover to protect enemy defensive installations. The assault upon it was characterized by a prodigious use of direct fire artillery, tanks, tank destroyers, and overhead artillery fire for one hour prior to the attack. In the final assault of the WaIled City, the 145th Infantry Regiment used an entire company of medium tanks, an entire company of tank-destroyers, a special assault-gun platoon, two flame thrower tanks, and the regimental M-7's from the Cannon Company plus an additional platoon from the 148th Infantry. Artillery pieces up to and including 155mm howitzers were used in direct fire missions also, but their particular vulnerability to small arms fire precluded their extensive use. Great difficulty was had in getting direct fire weapons across the Pasig River and into position because of the intensity of enemy fire. The whole attack on Intramuros was delayed until the heavy assault guns could be brought over and placed into battery. The main purpose of the direct fire was to breach the walls, and two places were selected where the masonry was to be opened. Such was the organization of fire that each gun had its own part of the area in the wall to be destroyed. The hour's bombardment, however, did not open the wall cleanly, but rather crumbled it so that foot troops could climb over without having to use ladders. When the breaches were made, one at the North end of the city and the other at the Northeast corner, the assault units moved in.

The 129th Infantry attacked across the Pasig River from the North in assault boats (after shooting steps into the river embankment with 76mm tank destroyers), while the 145th Infantry attacked overland from the West. So heavy was the preparation, that entrance was gained almost without opposition. Once our units were inside Intramuros, normal street fighting again took place, except in Fort Santiago. This was a medieval fort, containing many dungeons and deep recesses and tunnels, filled with Japanese. Among the expedients found workable in combating the enemy therein was the sealing of deep cavities by demolition teams. The extinction of other pockets to which access was difficult was effected by pouring gasoline into them and igniting it with WP grenades.

The Parian Gate was one of the 7 gates of Intramuros - so named as it was the only portal by which the Chinese - parias (Hindu for "outcasts") - could enter and leave Intramuros.  The Parian Gate was, after 1765, the gate the new governor officially entered the city and received the keys.

In some cases it was very helpful to have an observation post in a high building some distance to the rear of the attacking units, with direct communication to the attackers. Because of the limited visibility in many cases this rear CP was able to observe and report to the attacking company actions and locations of the enemy. In closein fighting, the attacking companies should have the SCR 300 channel number of the adjacent units, so that in an emergency direct communication may be established by switching to the appropriate channel. This means is recommended only for emergencies or situations where the information might become worthless after a few minutes ; for example, enemy escaping from a strongpoint.

b. Use of Flame-throwing Tanks

In one instance, Japanese held the second floor of a building and commanded the stairways by the use of hand grenades thrown from sandbagged positions out of sight. A flame-throwing tank was brought into the doorway and maneuvered into position to shoot flame up the stairs into enemy defenses. The Japanese were driven out and the assault troops siezed the stairs. On another occasion a flame-throwing tank discharged its flame through a window into a deeply recessed and sandbagged machine gun position, destroying the enemy.

c. Effect of Unfused Projectiles on Walls

Considerable advantage was thought to be gained by the use of unfuzed 155mm HE shells for the purpose of opening holes in heavy walls. While the ballistic properties are not noticeably different without the fuze, observers agreed that the initial penetration with unfuzed shells created a more pronounced fissure than was caused by the use of HE with fuze delay. This fissure responded readily to subsequent use of HE with fuze delay.

 d. Night Operations

Night attacks through the rubble and debris of a defended city are extremely difficult and hazardous. The many hiding places make it impossible to keep from bypassing Japanese who have to be hunted out the next day. Movement is difficult and silence is almost impossible. Any attacks made at night in the city should be local and against known positions and terrain. Attacks against buildings should not be launched after 16001 . The enemy had the distinct advantage of being in the dark while our troops were definitely silhouetted when approaching the building. Also the large number of mines used by the Japanese in Manila made night movements extremely dangerous. Moves of a minor nature are desirable and advantageous, but large-scale and continuous moves should be avoided. Usually the danger of disaster involved is too great to compensate for the advantages gained.

8. Conclusions

a. Street fighting in Manila was normal and advanced no principles or tactics not already covered in FM 31-50.

b. The stubborn Japanese defense of large fortified buildings standing in open ground necessitated use of combined tactics of assault on fortified positions and combat in towns, in order to secure their reduction.

c. The unique situation of assaulting a medieval rampart presented itself. Large numbers of assault guns and artillery pieces including those of medium caliber were laboriously and dangerously emplaced within close range of the rampart, and only after employing direct fire and heavy bombardment did the guns succeed in driving the defenders from the walls and opening breeches for assaulting troops.