Operation Mike VII

'Mike VII' was a US amphibious landing at San Antonio in central Luzon in the Philippine islands group (29 January 1945).

Undertaken by Major General Charles P. Hall’s XI Corps of Lieutenant General Robert L. Eichelberger’s 8th Army, the landing put Major General Roscoe B. Woodruff’s 24th Division and Major General Henry L. C. Jones’s (from February Major General William C. Chase’s) 38th Division ashore on the west coast of Luzon in an area to the north of the Bataan peninsula with the object of taking the naval base at Olongapo and pushing forward to the northern shore of Manila Bay.

Rear Admiral Arthur D. Struble’s 9th Amphibious Group landed the 38th Division and 34th Regimental Combat Team near Zambales, to the north of Subic Bay, on 29 January. About 30,000 troops were disembarked in one day from 22 transport vessels and 35 tank landing ships. Air support was provided by Major General Ennis C. Whitehead’s 5th AAF, the landing forces were escorted by 14 destroyers of Destroyer Squadron 49 and destroyer escorts, 11 minesweepers and 19 motor minesweepers, and fire support was provided by Rear Admiral Ralph S. Riggs’s Task Group 74.2 comprising the light cruiser Denver and two destroyers.

On 30 January four troop-carrying destroyer conversions and the vehicle landing ship Monitor landed a battalion landing team of the 38th Division on Gamble island in Subic Bay. Distant cover for both operations was provided by Rear Admiral Russell S. Berkey’s TG74.3 comprising the light cruisers Boise, Phoenix , Australian heavy cruiser Shropshire, and four destroyers. The Japanese submarine Ro-46 torpedoed the 7,800-ton attack transport Cavalier.

There were no significant Japanese forces in the Bataan peninsula, but nonetheless it took the XI Corps some two weeks of steady fighting to reach Manila Bay. The corps then undertook the clearance of the Bataan peninsula with an overland advance down the peninsula’s eastern side starting on 14 February, and complemented this one day later by the landing of the 151st Regimental Combat Team at Mariveles at the southern tip of the peninsula while another force assaulted Corregidor. The landing force embarked at Subic Bay for Mariveles was commanded by Struble. Corregidor was also itself to be assaulted on 15 February by an amphibious force drawn from the 34th Infantry and an air drop by the 503rd Parachute Infantry. Minesweepers were to start sweeping the approaches sweeping on 13 February, and would be followed by a bombardment force under Berkey.

As well as woefully underestimating the Japanese garrison of Corregidor, MacArthur’s intelligence had also seriously overestimated the Japanese force on Bataan, which numbered only 1,400 men, of whom only a few were in the area of Mariveles.

Berkey was concerned deeply by the lack of any Japanese reaction to operations of the the minesweeper force, which he had hoped would reveal their artillery positions. Berkey’s ships began their gunfire bombardment at 09.43 on 14 February and the Japanese finally responded by firing on the minesweepers from Corregidor and Caballo. The Japanese fire was intense until 10.18, when the minesweepers completed their task after sweeping 76 mines and withdrew without loss.

The destroyer force off Mariveles had a harder time of it. Fletcher was struck by a 6-in (152.4-mm) shell which started a brief fire, the yard minesweeper YMS-48 was hit and set on fire, and the destroyer Hopewell took four hits which inflicted 19 casualties and forced the ship to withdraw to Manus island. The minesweepers then moved into the harbour, but the destroyers La Vallette and Radford both were mined and forced to withdraw. The destroyers were in waters which had already been swept twice, suggesting that the Japanese had used mines of a type more sophisticated than their usual moored contact mines.

The landing force arrived at 10.00 on 15 February and encountered negligible opposition ashore, but LSM-169 hit yet another mine. Early in the morning of the following day, some 20 kamikaze boats penetrated Mariveles harbor, sank LCS-7 and LCS-49, and disabled LCS-27. Bataan was declared secure on 21 February.

There then remained the four fortresses on islands in Manila Bay. The largest of these is Corregidor, which by December 1941 the USA had turned into one of the most strategically important fortresses in the South-West Pacific as it commanded the entrance to the superb anchorage of 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 hilly 'head' and 'tail' of this 'tadpole' are connected by a low-lying isthmus known at the time as Bottomside. To the east of Bottomside, on the 'tail', is Malinta Hill, which contained the headquarters of the island in a tunnel dug deep into the hillside. The eastern side of the head (Middleside) had the officers' living areas while the western side (Topside), which rises to a height of 500 ft (150 m), had the barracks and parade grounds. The island was covered with trees and scrub, but possessed a good road network and a 2,400-ft (730-m) airstrip, known as Kindley Field, on the eastern end of the 'tail'.

In December 1941 Corregidor accommodated powerful coastal artillery in the form of 23 batteries with 56 guns ranging in calibre from 3 to 12 in (76.2 to 305 mm).

Fort Hughes, built on nearby Caballo Island, comprises three hills reaching a maximum height of 380 ft (116 m) and had 11 batteries of gun ranging in calibre up to 14 in (356 mm).

Fort Drum, constructed on a tiny islet slightly more than 4 miles (6.5 km) to the south-south-east of Corregidor island, had been built up into a ship-shaped concrete fortress whose battery comprised four 14-in (356-mm) guns in two twin turrets and four 6-in (152.4-mm) guns.

Fort Frank, on Carabao island some 7.5 miles (12 km) to the south of Corregidor island and just 500 yards (460 m) from the southern shore of Manila Bay, had 19 guns in calibres ranging up to 14 in (356 mm).

In December 1941 these island defences had been manned by 5,700 US and Philippine Scouts troops of the 59th, 60th, 91st and 92nd Coast Artillery Regiments, and the batteries rendered Manila Bay all but impenetrable to a conventional attack from the sea. Even in Manila fell, as long as they held out they dominated the bay and, it was believed, leave the harbour useless to the Japanese. What the USA did not appreciate, however, was the fact that the largest-calibre anti-aircraft guns were of 3-in (76.2-mm) calibre and therefore unable to reach high-flying Japanese bombers, and also the fact that Corregidor island was also vulnerable to artillery fire from the southern tip of the nearby Bataan peninsula, just 3,500 yards (3200 m) to the north, and could not hold out for any sustained period should the Bataan peninsula fall.

By February 1945 the Japanese garrison on Corregidor island numbered 6,000 men under Colonel Akira Itagaki, and had constructed additional field works. However, MacArthur’s intelligence estimated that Corregidor island was garrisoned by only 850 men and the Bataan peninsula by 6,000 men, and it was this latter which had persuaded MacArthur to assign the task of taking Mariveles, on the southern tip of the Bataan peninsula, to Chase’s 151st Regimental Combat Team.

The best dropping zone for the planned airborne assault on Corregidor island was Kindley Field, but this would require the troops to land under the fire of guns sited above the dropping zone and then fight uphill against strong fortifications. It was therefore decided to run the risk of dropping the force on the small parade ground and golf course on Topside. The preliminary bombardment at 06.30, which was carried out by a force of eight cruisers and 14 destroyers, was succeeded by an air attack at 08.00 36 Consolidated B-24 Liberator heavy bombers and 31 Douglas A-20 Havoc attack bombers. Although the preliminary bombardment inflicted only light losses on the Japanese in their deep entrenchments, it stripped much of the island of its covering vegetation, and also triggered landslides which sealed some 2,000 of the defenders inside Malinta Tunnel.

The first echelon of paratroops, men of the 3rd Battalion of Colonel George M. Jones’s 503rd Parachute Infantry, began to jump at 08.30. Most hit their dropping zones, but a small number did not and had to be rescued from the harbour by PT-boats, and one group of 25 men fortuitously dropped right on top of Itagaki’s position, surprising and killing him. This destroyed the cohesion of the Japanese defence almost from the start of the battle. The paratroops had suffered as well, with 25% casualties from landing mishaps or Japanese fire. Even so, the paratroops quickly took and secured positions overlooking the planned amphibious landing beaches at Bottomside.

At 10.30 the assault battalion of the 34th Infantry came ashore in five waves in the area to the south of Malinta Hill, of which only the fifth wave took any significant fire. A second wave of paratroopers dropped at 12.30, landing precisely on target. However, casualties were so high from Japanese fire at the descending paratroops that a third wave, which had been scheduled to jump on the following day, was instead delivered by landing craft.

The task of reducing the dug-in Japanese defenders took 10 days, with the Americans moving slowly forward during the day and the Japanese staging bloody but futile banzai charges during the nights. Almost the whole Japanese garrison was killed. The Japanese trapped in Malinta Tunnel attempted to blast their way out with 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 US 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 detonated their own magazine. The explosion blow over one of the Sherman tanks, killed 52 Americans and wounded another 144, and killed the 150 Japanese in the tunnel. The next day the last organised resistance on the island collapsed.

The US casualties totalled 455 men dead and 550 wounded, which was nearly a third of the attacking force. More than 4,200 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 now eliminated, starting with Ternate on the mainland to the south on 2 March and Fort Hughes on 27 March.

The latter, on Caballo island, was assaulted by a battalion combat team of the 151st Infantry, which overran the island on the first day, but then spent four days trying to flush out the Japanese in their tunnels. Engineers then tried pouring Diesel oil into the tunnels and igniting it, but this also failed until the US Navy supplied a pipeline, pump, and two oil barges to allow 2,500 US gal 9465 litres) 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 on El Fraile island was taken in the same fashion. The US troops landed away from the entrance, which was swept by heavy Japanese fire, and pumped 3,000 US gal (11355 litres) of oil into the fortress from its roof. This was followed by a 600-lb (272-kg) delay-fused explosive charge. The US troops withdrew and the detonation of the charge then triggered secondary explosions which continued for days and completely wrecked the fortress.

Fort Frank on Canabao island was assaulted on 16 April and found to have already been evacuated.

Away to the north of this region, the remnants of the 'Kembu' Group were holding out under Major General Rikichi Tsukada. After losing Clark Field, the 'Kembu' Group's surviving 25,000 men had fallen back into the Cambusilan mountains, where they were kept in check by Major General Rapp Brush’s 40th Division of Lieutenant General Oscar W. Griswold’s XIV Corps, which was too concerned with the reduction of Manila to undertake anything but containment of this Japanese thorn; eventually the 40th Division was supplemented by the 38th Division and Major General Leonard F. Wing’s 43rd Division, and the 'Kembu' Force broke up into small guerrilla units on 6 April. These remnants survived to the end of the war, when some 1,500 survivors surrendered.

The overall Japanese losses in the Luzon campaign thus amounted to some 190,000 men, while those of the Americans were 8,000 men dead and another 30,000 wounded.