The Lull May 15-May 21
The Japanese are forced to call a short halt to their full scale bombardment as ammunition has to be moved up, a number of guns have worn out from continuous firing, and the malarial epidemic has reached its peak, with many guns operating with half or less of their gun crews and those that are not sick are exhausted. Only the Kondo Detachment continues its nightly harassment shelling, while the Japanese Army Air Force continues its daily bombing efforts. Little actual damage is inflicted on either Fort Mills or Fort Hughes but counter battery efforts by the mortars of Battery Way and Battery Geary continue to be unsuccessful in silencing the Japanese harassment attacks. The Americans do try an experiment, firing several 12 inch mortar rounds at a particularly large Japanese air raid in hopes that the fuses can be adjusted to inflict a nasty shock on the Japanese. This effort however fails due to technical reasons and is not attempted again. With one of the 3 inch antiaircraft batteries wiped out (Battery Denver), and with radar and many of the spotting stations damaged or knocked out, fire is becoming less effective against the Japanese raids, although at least 60 Japanese bombers have been shot down by Harbor Defense Command since the start of the war. This slackening of American effectiveness is noted however and the bombardment plan for the next stage of the battle is adjusted accordingly.
The 2nd Bombardment May 21-24
The commanding general of the 7th Artillery Command orders the 75 mm guns to remain silent this time, as they are only drawing fire and doing little effective work. His 105 mm guns are given a general area bombardment mission, with the goal of knocking out communications and preventing day time movement and repairs. His heavier guns are given the mission of silencing gun positions, with the 150 howitzers and guns targeting known and identified antiaircraft batteries, while the 240 mm howitzers concentrate on the American 12 inch guns and mortars.
The air bombardment is also modified. The medium bombers are switched to night attacks with the goal of harassment and keeping the Americans busy while landing craft are moved to Marivelles and Cavite from Subic Bay since a small gap in the minefield between Bataan and Corregidor has finally been created. The light bombers are ordered to press their attacks on Fort Hughes, which needs to be neutralized, and the Kondo Detachment is given the day time mission of knocking out its antiaircraft guns.
The bombardment is ferocious and inflicts terrible damage. The most catastrophic is a 240 mm round that penetrates an already badly beat up magazine at Battery Geary and sets off a massive explosion that wipes out all but one of the eight 12 inch mortars (leaving only an old M1896 operational) and killing or wounding most of the battery personnel. But while not as spectacular, the constant shelling knocks out the guns of Battery Smith (12 inch) Battery Crockett (12 inch guns), Battery Morrison (6 inch), Battery Chicago (3 inch AA), Battery Rock Point (155 semi-fixed), Battery Stockade (155 semi-fixed), Battery Grubbs (10 inch) and all but one of the mortars of Battery Way. Only Battery Malinta (a single 8 inch gun which has remained silent to this point and under cover), a few 155 guns and a pair of mortars remain operational. Over half of the 3 inch antiaircraft guns are damaged beyond repair or destroyed, and the targeting systems for the antiaircraft command have all been damaged beyond repair as well.
Meanwhile the Japanese take the opportunity to move their landing craft at night and begin final preparations for an assault.
The Japanese still do not get things all their own way. A lucky hit from Battery Geary destroys an artillery ammunition dump that sets off a chain reaction that also takes out the crews of an entire battery of 105 mm guns, while other occasional lucky hits add to the Japanese casualties, including a 12 inch HE round from Battery Way that wipes out an entire Japanese battalion aid station, killing or wounding the staff and all their patients.
The battery personnel from the knocked out guns of Fort Mills and Fort Hughes are reorganized into provisional infantry companies, and as only a few 155 guns and the 14 inch guns are still active on Fort Hughes, most of that island fort now consists of beach defense troops. The provisional infantry companies on Fort Mills are formed into a beach defense battalion and take over the defense of Bottomside from the Marines, who are moved inside Malinta Hill to form another reserve.
Final Softening Up
On May 25, the Japanese shift their fire. The heavy guns concentrate on Malinta Hill, as the Japanese are convinced that if it can be destroyed the Americans will surrender. Even 400 pound shells can not penetrate through the hill and the tunnels survive, although dust is heavy and by accident the 8 inch gun of Battery Malinta is damaged beyond repair. The lighter 105 and now the 75 mm guns open fire on likely American defensive positions on Tailside and Bottomside, while the heaviest two bombing raids of the campaign, involving nearly every Japanese Army aircraft on Luzon, plasters both islands, and as American antiaircraft fire has become markedly less effective. However a few low level attacks suffer unexpected casualties from a withering barrage of heavy machine gun fire and several Japanese light bombers are shot up, with four crashing into the ocean. The remaining American batteries are ordered to remain silent however, as General Moore is expecting the Japanese to make their amphibious assault soon, within at least another 48 hours, based on the experience of Fort Frank.
