The Fort Hughes Operation
On 27th March, the 2d Battalion, 151st Infantry, 38th Division, reinforced by B Company, 113th Engineers, made the assault on Caballo, hard by Corregidor in Manila Bay. It was a small island heavily studded in the past with Coast Artillery materiel, mortar pits, tunnels, and the whole protected by steel reinforced concrete.
A week previously a reconnaissance platoon had gone in and had its ears pinned down and had to be withdrawn. They had trouble getting off because the Japs on the heights had mortar, machine-gun, and small-arms fire trained on the beaches, directed mostly from the plateau which lies halfway up the highest hill. The reconnaissance did reveal that the enemy's main defenses were on this plateau.
Then, on the morning of the 27th, the assault struck and in one and a half days the entire top surface was in our control, but the Japs were in force in the tunneled workings which enter the base of the hill, not unlike the Malinta Tunnel on Corregidor, and the two pits, called for convenience in this article, East Pit and West Pit.
The main hill, or dominating ground on the island, rises to a height of 371 feet, from the bench mark reading in the old OP there. The original plan called for E Company to make the assault on this hill (termed Hill 2), a difficult climb as it was bare of vegetation and almost entirely raw rock by this time of the operation.
G Company was to follow E and do the mopping up, while F was held in reserve at Corregidor.
Thus with E's mission to gain the eminence so speedily that no time was to be taken to knock out Jap pillboxes but to infiltrate to gain top terrain, the infantry pushed off.
Dragging themselves upward as best they could, "E" had made only short progress when they were trapped by Jap mortar fire and pinned down. They could neither continue up nor come down because the Japs' well-aligned fire from the old mortar pits on the plateau had complete command of the terrain. The Japs had most of the fire power directed on the skyline.
E Company was finally able to withdraw under heavy covering fire from G, and the use of smoke, and to shift their attack to the left, or southerly side of the hill. The ground was so chewed up by artillery fire and repeated bombings that this was almost a superhuman effort, but by night ten men had made the top of left knob. The rocks dislodged by those in front caused slides on those in the rear and cover against the bare side of the slope was difficult, practically nonexistent, but our infantry accomplished its mission. The object was to traverse the top of the hill from left to right ending on right knob. In so doing there was a gulch between the two knobs which was subjected to terrific machine-gun fire. The Japs could fire out of the pits with their guns prefixed. During the night the boys bragged that a whole platoon had crowded into and got protection in a depression not more than three feet deep and about ten feet square. It required twenty hours to take the summit. Going was so slow and enemy fire so intense that a head raised slightly was the signal for immediate enemy fire. One lad raised up and was hit in the head. Out of his mind, he was dragged back by his buddies, but in his struggle he broke away from a 200-pound infantryman and raised up again. He met a burst of machine-gun fire, killing him instantly. The moonlit night added to the difficulty but finally by use of a length of rope the rest of the platoon was dragged up, and the hardest job, so the Battalion Commander (Lt.Col. Paul R. Lemasters) thought, was over, but . . .
On the 28th, a smoke concentration was laid just under the crest of Hill 2 by artillery emplaced on Bataan, and infantrymen of G Company crawling within grenade range of the troublesome pits hurled phosphorus grenades into them.
"We knew we weren't killing the Nips but we wanted to keep their fire down, and block the targets we were offering them by our advance across the skyline, the only route over to right knob," said Lt. Maurice P. Murphy, the Battalion's S-2.
By this time E Company was getting across to right knob, the highest point on the island. From here patrols were able to walk down the west side, and the whole island was, or should have been, under our control.
But we fought eleven long days to clear the Japs out of the tunnels and pits, and some few were still there.
Possibly all veteran Coast Artillerymen know how these mortar pits were constructed and the general fortification plan of Caballo. Those at Fort Hughes were two in number, some forty feet square and approximately thirty feet deep, with tops open. The walls were constructed of concrete heavily reinforced with steel, and were from eight to ten feet thick.
The pits were about fifty feet apart, interconnected underground with a maze of tunnels and shafts running off each corner and sides of the pits proper. This vast underground network was well ventilated and well drained, the drainage system opening out of the side of the hill on the north. The tunnels were so large the Japs could easily move around in the alleyways in the concrete, and were so interlaced, that an infantryman said later, "a couple of men could play tag in there and one wouldn't see the other in two days". The Japs were sandbagged in, with slits so narrow that only machine-gun and rifle barrels could protrude. Grenades thrown against them did no damage. The Japs sat back in the darkness and as soon as an American stuck his head over the edge of the pit–"ping" and another casualty was counted. Now came a series of plans. So many high-ranking officers had gathered from USAFFE by this time and so many suggestions made that the GI's called the CP the "Eagles Nest." So perplexed was the Battalion Commander he was willing to take a chance on almost all offers. The tactics used were so varied no effort was made to set them down in detail, but roughly this was the procedure:
1. Infantrymen crawled to grenade range and threw in grenades, both fragmentation and white phosphorus. They used the new bazooka, with both HE and WP rockets–the latter by the way, a wonderful weapon in the Pacific War. Strong boys of the battalion also were enlisted to throw 25-pound satchel charges (demolition) into the pits. Result: the Japs withdrew into the safety of the tunnels, and came back later to defend their positions.
2. It was now dark and efforts ceased to penetrate the pits until daylight. A harassing mortar barrage was laid down all night—as on subsequent nights, to keep the Japs in the tunnels. At dawn a battery of 155's on the mainland at Cabcaban threw in a concentration of shells, using a special concrete-piercing shell, designed to penetrate eight feet or so before exploding. But the trajectory was so high the shells lost their effectiveness. Result: failure.
3. The idea of smoke pots was advanced. Dozens were brought to the scene, the plan being to smoke out the Japs or failing to do this, reveal the general exits. The pots were fired and tossed in as simultaneously as possible. Some new exits were discovered, and smoke poured out of East tunnel, a huge reinforced tube similar to Malinta Tunnel on Corregidor. As to driving the Japs out into the open – result, failure.
4. During the use of the smoke, it was noticed that the Japs got very excited when anything happened about the entrance to East tunnel. The Japs had a machine gun in there and defended it with feverish intensity. A destroyer was called upon to fire point blank at the opening of the tunnel. After several hours of firing the opening was closed except for two or three feet at the top. Engineers and infantrymen with pick and shovel mounted the hill above the opening and finished the job. This was merely an interval, and no hope was held that this would drive the Japs out.
5. There were any number of dud bombs on Corregidor and a squad was over there blowing them up. Two 500-pound and two 250‑ pound bombs were deactivated, brought to Caballo, winched up to the ventilating shaft and lowered into the subterranean maze, where they were set off with a time fuse. The resultant explosion rocked the hill but it did not dispel the Japs. Both rank and file were now groping for ideas, "crazy or not", and Psychological Warfare was called in. A 30-minute truce was fixed and the psychological boys set up loud speakers and broadcast a message in Japanese, out-lining terms of surrender. Pamphlets were tossed about the pit. One Jap was seen to rush out, grab a pamphlet and dash back. This gave hope there might be a surrender. Another fifteen minutes was added to the truce. Result, failure.
6. Now, while it was later learned the Japs had the following plan in mind ever since the Americans landed, this action came without warning, and only alertness prevented it being more successful. The Japs pulled a banzai attack in commemoration of 4th April, their Army Day, or Heroes Day, and it was not merely a fanatical crazy thing, but well planned and executed. The Americans as they went to bed at dark had thought they could see twos and threes of Japs against the skyline and a little later heard digging. These strange doings led to suspicion but it was not realized that an attack was coming. All that night the Japs infiltrated out of the tunnels between mortar bursts, and gathered at a prearranged spot. The attack was launched at 0505–it had taken them all night to gather, and officers of the Battalion later admitted, "they damn near wiped out our CP."
E Company had been taken over to Corregidor for a rest and hot food, and an urgent radio message called them back. They arrived at 0730 and with their help the Japs outside the tunnel were killed. A total of eighty bodies was counted. A captured PW later told the S-2 that the force, able to slip out and go to "glorious death" was 120 and that thirty had survived the banzai, many of them wounded.
7. During the operation someone mentioned the use of oil, and other plans having failed, it was decided to try it. An LCM was engaged to pick up several drums of oil and gasoline on Corregidor and haul it to Caballo. With the use of a 6 by 6 truck and extra cable on the winch threaded to the ventilating shaft on the plateau, some 15 drums were winched up. The engineers had succeeded in pouring about three drums down the shaft-this shaft protruded some feet above the ground, and the drums had to be hoisted one at a time, a slow process. The Japs opened with mortar fire and tracers. They had to abandon the idea-it was too slow, and the men about the ventilating shaft could have been set afire. So, another failure.
8. Someone suggested the use of tanks. Three were brought from the mainland, and after difficulty were unloaded from the LCM's and attempts made to get them up the hill. One started out on a circuitous route upward. It toppled into a 1,000-pound bomb crater and is there yet. The second was almost in a position to fire into the pit when its commander attempted to change its position and ripped a track off. The engineers put it back on, and the third decided there was no use trying to get up the hill. Now about this time the pipeline was started. Four-inch pipe was procured and laid from the LCM's anchored on the south side of the island to the very edge of east pit, a distance of some hundred yards, and oil mixed with gasoline was pumped nearly all day. Thousands of gallons were spilled into the pit, and then set afire by mortar shells. There was a large fire, some minor explosions, but the Japs were still there. The next day, after patrols went up to investigate, they were met with a hail of lead, but to less extent than formerly. Moreover, they discovered a Jap sniper had almost shot the line in two with continual rifle fire at one spot. Also, Japs during the night had planted land mines about the top of the pit, hoping no doubt, that they would be stepped on when work started again on the pipe. They had made no effort to destroy the pipe or throw it over the hill-just another problem for the psychology boys to figure out. The mines were removed and the pipe nozzle shifted over to the right pit and another 3,000 gallons of the gas- oil mixture pumped in. This fire really burned, and explosions were heard deep down in the earth for hours after the oil ignited.
As further example of the Japanese will to fight, despite the flood of oil and previous poundings they had taken, they made a futile attempt to drain the oil out the side of the hill. An alert machine gunner saw the oil spurting out the drainage system and set it afire with tracers.
The next day a patrol was sent into the workings to look for stragglers, or any Japs who still might be alive. One was found and killed.
Between fifty and sixty dead Japs were found in the tunnels. Where mortars had roared and rifles cracked for eleven days there was silence.
Corps headquarters gave permission for the Battalion to withdraw provided a patrol was sent over each day to reconnoiter the area. The very first day of such patrols, an American was killed by a sniper, and on the second day, two were killed and three wounded.
Search as they might the patrols could find no additional snipers. "We couldn't figure it out unless the Japs swam over from other islands," one officer said.
Then more than two weeks after Caballo fell and the 1st Battalion of the 151st Infantry was sent over, the Commanding Officer was killed the first day as he peered into a tunnel. Yet despite all this terrific effort and tough fighting, a total of only 280 dead Japs was counted. Three were taken prisoner. Truly a compliment to original planning of the coastal defenses of Fort Hughes.