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Corregidor


Relief map of Corregidor

Photograph of Corregidor

U.S. Navy. Via Wikipedia Commons

Corregidor (120.589E 14.390N) was one of the most strategically important fortresses in the Southwest Pacific, commanding the entrance to Manila Bay. The island is tadpole-shaped, 3.5 miles (5.6 km) long and 1.5 miles (2.4 km) across its head. The isthmus where the head joins the tail was known as Bottomside and is shown in the modern photograph above. East of Bottomside was Malinta Hill, which contained the headquarters of the island in a tunnel dug deep into the hillside. The east side of the head (Middleside) had the officers' living areas while the west side (Topside), which rose to 500' (150 meters) above sea level, had the barracks and parade grounds. The island is covered with trees and scrub but had a good road network and a 2400' (730m) airstrip, Kindley Field, on the east end of the tail.

Corregidor was deeply dug in with powerful coastal artillery, consisting of 23 batteries of 56 guns ranging from 3" (76mm) to 12" (305mm) caliber. Fort Hughes, built on nearby Caballo Island, consisted of three hills reaching to 380' (116 meters) and had eleven batteries of seventeen up to 14" (356mm) in caliber.

Photograph of Fort Drum

U.S. Army. Via ibiblio.org

Fort Drum, built on a tiny islet just over four miles (7 km) south-southeast of Corregidor, had been built up into a concrete behemoth whose battery consisted of two twin 14” gun turrets and four 6" (76mm) guns.  Fort Frank, on Carabao Island 7.5 miles (12 km) south of Corregidor and just 1500' (460 meters) from the south shore of Manila Bay, had 19 guns of up to 14" (356mm) caliber. These defenses were manned by 5700 U.S. and Philippine Scouts troops of 59, 60, 91, and 92 Coast Artillery Regiments.

These impressive coastal batteries made the harbor all but impenetrable to a conventional attack from the sea. As long as they held out, even if Manila fell, the harbor would be useless to the Japanese. However, the largest antiaircraft guns were just 3" (76mm) in caliber and would prove unable to reach high-flying Japanese bombers. Corregidor was also vulnerable to artillery barrage from the tip of the nearby Bataan Peninsula, which was just two miles (3 km) to the north, so that it could not hold out long if Bataan fell.

First Battle of Corregidor

During the first Philippine Campaign, the American forces were forced to retreat into the Bataan Peninsula to make a last-ditch stand against the Japanese. MacArthur established his headquarters at Corregidor and placed Wainright in command on Bataan. Corregidor was defended by 4 Marine Regiment, which had been evacuated to the Philippines from China shortly before hostilities broke out. When MacArthur was ordered to escape to Australia, on 11 March 1942, Wainright shifts his headquarters to Corregidor, leaving King in immediate command on Bataan.

King's line collapsed on 6 April 1942 and he felt compelled to surrender his forces two days later. The Japanese immediately began moving heavy artillery to the southern tip of Bataan Peninsula, and began systematically reducing the gun emplacements on Corregidor. The first Japanese battalion, from 61 Regiment, landed on 5 May on the tail of the island near the airstrip and encountered fierce resistance from the Marines. However, the Japanese managed to bring a second battalion and several light tanks ashore, and the Marines had no antitank weapons to speak of. Wainright surrendered the next day, as the Japanese brought in a third battalion and were closing in on Malinta Tunnel with its underground hospitals. Total American casualties were around 800 killed and another 1000 wounded. Japanese casualties were very heavy but the exact number is uncertain. They have been claimed to have been as high as 900 dead and 3000 wounded, which would be the better part of the three attacking battalions.

Second Battle of Corregidor

By February 1945 the Japanese garrison on Corregidor numbered 6,000 men under Colonel Itagaki Akira, and these had constructed additional field works. However, MacArthur's intelligence estimated the Corregidor garrison at just 850 and the Bataan garrison at 6000, and MacArthur assigned 151 Regimental Combat Team (Chase) to take Mariveles on 15 March 1945. The landing force would embark at Subic Bay and was commanded by Admiral Struble. Corregidor itself would be assaulted on 15 February by an amphibious force drawn from 34 Regiment and an air drop by 503 Parachute Regiment. Minesweepers would commence sweeping on 13 February and be followed by a bombardment force under Admiral Berkey.

Besides greatly underestimating the Corregidor garrison, MacArthur's intelligence had badly overestimated the Japanese force on Bataan, which numbered only 1400, of which very few were anywhere near Mariveles. Berkey was "extremely perturbed" (Morison 1959) by the lack of any Japanese reaction to the minesweeper force, which he hoped would reveal their gun positions. Berkey began his bombardment at 0943 on 14 February and the Japanese finally responded by firing on the minesweepers from Corregidor and Caballo. Fire was intense until 1018, when the sweepers completed sweeping 76 mines and withdrew without loss.

The destroyer force off Mariveles had a rougher time. Fletcher took a 6" (155mm) shell hit that started a brief fire, YMS-48 was set afire, and Hopewell took four hits that inflicted 19 casualties and forced the destroyer to withdraw to Manus. The minesweepers moved into the harbor, but LaVallette and Radford both were mined and forced to withdraw. The destroyers were in waters that had already been swept twice, suggesting the Japanese had used more sophisticated mines than their usual moored contact mines. The landing force arrived at 1000 on 15 February and encountered negligible opposition ashore, but LSM-169 hit yet another mine. Early the next morning, about twenty suicide boats penetrated Mariveles harbor, sank LCS-7 and LCS-49, and disabled LCS-27.

The best ground for the airborne assault on Corregidor was Kindley Field, but this would require the troops to fight uphill against strong fortifications, and the decision was made to risk dropping the force on the small parade ground and golf course on Topside. The preliminary bombardment at 0630, which was carried out by a force of 14 destroyers and 8 cruisers, was followed by an air strike at 0800 by 36 B-24s and 31 A-20s. Although the preliminary bombardment inflicted relatively light casualties on the deeply-entrenched Japanese, it stripped much of the island of its covering vegetation, and it also triggered landslides that sealed some 2000 of the defenders inside Malinta Tunnel. 

The first echelon of paratroops, from 3 Battalion, 503 Parachute Regiment, began jumping at 0830. Most hit the landing zones, but a few had to be rescued from the harbor by PT boats, and one group of 25 paratroops serendipitously came down on top of Itagaki's position, surprising and killing him. This destroyed the cohesion of the Japanese defenders almost from the start of the battle. The paratroops had suffered as well, with 25% casualties from landing mishaps or Japanese fire. However, they quickly secured positions overlooking the planned amphibious landing beaches at Bottomside. At 1030 the assault battalion from 34 Regiment came ashore in five waves south of Malinta Hill, of which only the fifth took any significant fire. A second wave of paratroopers dropped at 1230, landing precisely on target. However, casualties were so high from Japanese fire at the descending paratroops that a third wave scheduled to jump the next day was brought in by landing craft instead.

Reducing the dug-in Japanese took ten days, with the Americans slowly rolling forward during the day and the Japanese staging bloody but futile banzai charges after dark. Virtually the entire Japanese garrison was killed. The Japanese trapped in Malinta Tunnel attempted to blast their way out with high explosives on the night of 20 February, but the explosion set off a large magazine whose explosion annihilated most of the Japanese and buried six American paratroops in landslides outside the tunnel.On 24 February the Americans began clearing the tail of Corregidor, advancing behind two tanks brought in with the amphibious landings. A second massive explosion rocked the island on 26 February, when Japanese holding out in the Radio Tunnel (constructed in 1939 to shelter Corregidor's signals intelligence unit) set off their own magazine. The explosion flipped one of the Sherman tanks clear over, killed 52 Americans and wounded another 144, and killed the 150 Japanese in the tunnel. The next day the last organized resistance on the island collapsed.

Total American casualties were 455 dead and 550 wounded, which was nearly a third of the attacking force. Over 4200 Japanese dead were counted, with just 20 surrendering, and an estimated 200 were killed while trying to swim away and 500 were buried alive in the Malinta explosion. MacArthur personally attended the flag raising on Corregidor on 2 March.

The other Japanese units defending Manila Bay were mopped up beginning with Ternate on the mainland south on 2 March 1945 and Fort Hughes on 27 March. Fort Hughes was assaulted by a battalion combat team from 151 Regiment which overran the island the first day, but then spent four days trying to dig out the Japanesein their tunnels for the next four days. Engineers then tried pouring diesel oil into the tunnels and igniting it, but this also failed until Navy forces supplied a pipeline, pump, and two oil barges to allow 2500 gallons (9500 liters) of oil to be pumped into the tunnels and ignited with white phosphorus. This treatment was repeated over the next two days, and the last Japanese survivor was killed by a patrol entering a tunnel on 13 April.

Fort Drum was given the same treatment. The troops landed away from the entrance, which was a deadly fire zone, and pumped 3000 gallons (11,000 liters) of oil into the fortress from its roof. This was followed by a 600-pound (270-kg) explosive charge on a delayed timer.  The troops withdrew and the charge went off, setting off secondary explosions that continued for days and completely wrecked the fortress. Fort Frank was assaulted on 16 April and found to have already been evacuated.


References

CorregidorIsland.com (accessed 2008-2-14)

Devlin (1979)

Dunnigan and Nofi (1998)

Rottman (2002)

Sears (2008)

Stanton (2006)



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