Part Three: The Central Plains
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Chapter 8: Redeployment and Tactical Plans
The period 16-18 January was one of transition for both Sixth Army and 14th Area Army. For the Americans it was a period of planning and redeploying to fulfill General Krueger’s urgent desire to speed the pace of operations on the army left and to comply with new orders that General MacArthur issued directing Sixth Army to push XIV Corps on toward Manila more rapidly. For the Japanese, the same period found General Yamashita frantically trying to realign his forces for the better defense of the approaches to the Cagayan Valley and the Shobu redoubt.
New American Plans
Plans for Left Flank Operations
Growing dissatisfaction with the progress of operations in the I Corps zone, especially in the Damortis-Rosario area, played a large part in prompting General Krueger to formulate some of his new plans.1 A catalyst may well have been the failure of the 172nd Infantry, 43rd Division, to secure Rosario and the Routes 3-11 junction on 16 January, as planned.2 The Japanese had evacuated both locations, probably as the result of air and naval bombardment and long-range artillery fire, but on surrounding high ground they had plenty of artillery, mortars, and machine guns that covered all approaches. Col. George E. Bush, commanding the 172nd Infantry, knew, therefore, that he could hold neither Rosario nor the road junction until his troops had cleared the nearby dominating terrain.3 Wing, the 43rd Division’s commander, agreed, but while making provision for a new effort in the Rosario area also planned to destroy strong Japanese forces, including more artillery, along the Rosario-Damortis road between the 172nd and 158th Infantry Regiments, since the road could not be used until the Japanese pocket was cleaned out. General Wing directed the 158th RCT and the 63rd Infantry (to be attached to the 158th) to devote all their energies to the necessary clearing operations. Meanwhile, he limited the 172nd Infantry to holding action with its left
and to securing the high ground immediately north and northwest of Rosario with its right.
This plan left open to the Japanese both the Routes 3-11 junction and Route 3 south to Palacpalac, where the 169th Infantry was concentrating. With the prevailing fear of counterattack from the northeast – a fear certainly not abated after the events of the night of 16-17 January – it was imperative that the 43rd Division secure the road junction immediately. The division could accomplish this task within the foreseeable future only if the 103rd and 169th Infantry Regiments were to drive north up Route 3, simultaneously clearing dominating terrain east and west of the road.
Wheeling left along Route 3, the two regiments would leave behind them a huge gap between the 43rd Division’s right rear – to be anchored at Pozorrubio – and the 6th Division’s left, which was approaching Urdaneta. To fill this gap and to assure continued progress eastward toward the Army Beachhead Line, General Krueger, on 16 January, decided to commit another major portion of Sixth Army Reserve. He released to I Corps the 25th Division, less one RCT, to take over a wedge-shaped zone of attack between the 6th and 43rd Divisions. The 25th’s left would be based on roads running east and northeast to Pozorrubio; its right on roads leading southeast to Urdaneta. The division would first seize Binalonan and then secure Route 3 between Pozorrubio and Urdaneta.
The commitment of the 25th Division permitted General Swift, the I Corps commander, to lift his restrictions on the 6th Division’s advance toward Route 3, the Army Beachhead Line, and the Agno River. The division now directed its 20th Infantry to eliminate the Japanese known to be holding the Cabaruan Hills and ordered the 1st Infantry to strike east to seize Urdaneta, maintaining contact on the left with the 25th Division.
To provide added protection to XIV Corps’ left rear and to gather information on which to plan future advances, Krueger directed I Corps to reconnoiter south and east across the Agno in its zone. He issued no new orders to XIV Corps, which would continue to consolidate along the Agno, bring forward its supplies, and maintain its outposts south of the river.
New Plans for the Drive to Manila
Krueger intended to hold XIV Corps generally along the line of the Agno until Swift’s I Corps could overcome the resistance from Damortis to Urdaneta and, having thus eliminated the most immediate threat to the army’s left flank and base area, could begin maneuvering some of its forces south abreast of Griswold’s corps. It would be impossible, Krueger reasoned, to completely overcome the danger of counterattack on the left until he could commit the 32nd Infantry Division, the 1st Cavalry Division, and the separate 112th Cavalry RCT, all scheduled to reach Luzon toward the end of January. Then, but not until then, would it be safe in his opinion to mount an all-out drive toward Manila.4
General MacArthur, having assured the Joint Chiefs of Staff that he could secure the entire Central Plains-Manila Bay region within four to six weeks after
the assault at Lingayen Gulf,5 was unwilling to accept the two- or three-week delay in the drive toward Manila that Krueger’s plan foretokened. MacArthur was by no means as worried as Krueger that the Japanese would counterattack the extended left of the Sixth Army as its forces drove toward Manila, and, unlike Krueger, MacArthur did not think that the Japanese would defend Manila.6
It is readily apparent that MacArthur and Krueger were basing their plans on different intelligence estimates. General Willoughby, MacArthur’s chief of intelligence, had estimated that there were about 152,500 Japanese on Luzon and that these troops were scattered in three defensive areas – one north and northeast of Lingayen Gulf, another in the Clark Field region, and the third covering all southern Luzon, probably excluding Manila. Willoughby had further estimated that over half of the Japanese were located in the northern defensive area.7 By 17 January, as Sixth Army was redeploying in accordance with Krueger’s orders of the 16th, the army had over 175,000 troops ashore, at least 110,000 of them classed as combat personnel.8 Given Willoughby’s estimates, it is small wonder that MacArthur was unworried about the Sixth Army’s left and felt that Krueger would have little difficulty occupying Manila.
Krueger was basing his plans on quite different figures. His G-2, Col. Horton V. White, placed 234,500 Japanese on Luzon, an estimate approximating the actual Japanese strength of some 250,000 far more closely than Willoughby’s. White did not believe that the Japanese had as much strength on Luzon south of Manila as did Willoughby, and White felt that Manila would be strongly defended. Like Willoughby, the Sixth Army G-2 estimated that about half the Japanese on Luzon were in position to threaten the army’s left, but White placed some 50,000 more Japanese on the left than did Willoughby.9
In addition to his desire to seize Manila as early as possible, MacArthur had other reasons to push Sixth Army south more rapidly than Krueger’s plans would permit. Requirements of Pacific strategy, the theater commander radioed to Krueger on 17 January, made imperative the early seizure and rehabilitation of the Clark Field air center.10 Kenney’s Allied Air Forces manifestly needed air base facilities on Luzon far beyond the capacity of the fields that engineers could hurriedly prepare in the Lingayen Gulf area. Strategic air support requirements for Nimitz’ invasions of Iwo Jima and Okinawa alone made it necessary to develop heavy bomber fields on Luzon at an early date. The Allied Air Forces also needed to expand its base facilities in order to carry out its part in blocking the Japanese shipping lanes to the Indies and to provide adequate support for ground operations on Luzon. Finally, the Lingayen strips, not being all-weather fields, would probably wash out once Luzon’s rainy season began in late
April. The seizure of the Clark Field air center, with its prewar paved runways, its new paved strips the Japanese had constructed, its proximity to presumably repairable rail and highway facilities, and its location relatively close to the port of Manila, would go far toward meeting the air base requirements on Luzon.11
MacArthur had all these reasons for believing that XIV Corps both should and could move faster. He suggested to Krueger that the threatening dispositions of the Japanese on the Sixth Army’s left actually permitted a rapid advance at least as far as Clark Field on the part of XIV Corps. The theater commander right southward behind XIV Corps’ left proposed that Krueger echelon I Corps’ rear, thereby protecting XIV Corps while simultaneously containing – not necessarily attacking, it is to be noted – the Japanese forces on the army left. With such a plan in execution, MacArthur continued, it would not be necessary to hold XIV Corps back until I Corps could push strong forces south abreast. Even determined resistance by Japanese in the Clark Field area, MacArthur claimed, need not long delay XIV Corps, since such opposition would be “completely dislocated” by XI Corps, soon to land on the west coast of Luzon just north of Bataan Peninsula. MacArthur concluded with an order to Krueger to “direct . . . operations with a view to the earliest possible” seizure of the Clark Field air center.12
At this juncture Colonel White, revising his earlier estimates, began to feel that the proposed advance of XIV Corps might not be as risky as previously thought. By this time, the true pattern of the Japanese plan for the defense of Luzon had begun to crystallize for Colonel White, and on 17 January, about a week before Willoughby reached the same conclusion, White decided that the Japanese were not going to defend the Central Plains. He now estimated that XIV Corps would probably encounter no significant opposition until it reached Bamban, on Route 3 thirty-five miles south of the Agno River and just north of Clark Field. He guessed that the only strong Japanese force left in the Central Plains was the 2nd Tank Division, which he correctly suspected was displacing northward. And even if that Japanese division were still concentrated near Cabanatuan, twenty-five miles east across the Central Plains from Route 3 at Bamban, White did not feel that it could pose too much of a threat to XIV Corps – the destruction of intervening bridges and Allied air superiority would see to that.13
Despite these encouraging estimates from his G-2, General Krueger still felt that considerable risks were involved in any plan to speed XIV Corps toward Manila. He knew that behind MacArthur’s pressure was the theater commander’s desire to appear in the Philippine capital at the earliest possible date, and felt sure that MacArthur had in mind his birthday, 26 January, which was also Krueger’s.14 Krueger was not so confident that XI Corps’ landing north of Bataan would in any way upset
Japanese defensive plans in the Clark Field region.15 Moreover, in closer contact with XIV Corps’ situation than MacArthur, Krueger felt that the XIV Corps’ supply problems alone would slow progress. Finally, I Corps was developing so much opposition all across its front that Krueger believed the corps would be unable, as MacArthur suggested, to echelon enough strength southward on its right to protect XIV Corps’ left rear. Rather, Krueger foresaw that it would be necessary for XIV Corps to provide its own protection by echeloning its left to the rear, to this degree weakening its striking power for the advance southward.16
Nevertheless, Krueger had to alter his plans in accordance with MacArthur’s wishes, and on 18 January he issued new orders that provided for the execution of MacArthur’s directive by stages.17 XIV Corps, Krueger’s orders read, would move its main strength up to its former outpost line south of the Agno by 20 January. On the 21st, Griswold would push his right south along Route 3 to Tarlac, twenty miles beyond the Agno, and his left to Victoria, eleven miles northeast of Tarlac. Once on the Tarlac–Victoria line, the corps would make ready to move on toward Clark Field, leaving troops echeloned along its left rear to maintain contact with I Corps and cover a XIV Corps zone that Krueger now enlarged by pushing the I-XIV Corps boundary ten to fifteen miles eastward.
Krueger directed I Corps to secure Route 3 from Pozorrubio north to the Routes 3-11 junction as well as the stretch of Route 3 west to Damortis. Simultaneously, to help protect XIV Corps’ left rear, I Corps would advance its right east and southeast to a new line lying generally three miles east of Route 3 and extending southward to the eastern anchor of XIV Corps’ former outpost line. The I Corps would also send its reconnaissance forward to establish contact with XIV Corps troops at Victoria, and would then establish an outpost line running northeastward from Victoria approximately eight miles to the highway-railroad junction town of Guimba.
The I Corps’ task would obviously be the most difficult, but to accomplish its mission the corps had under its control the 43rd Division, the 6th Division, the 25th Division less the 35th RCT in Army Reserve, and the separate 158th RCT. The XIV Corps would advance southward through the Central Plains with the 37th and 40th Divisions.
Japanese Redispositions
Until XIV Corps reached the outposts of the Kembu Group in the Clark Field region, it would meet no Japanese other than scattered remnants of the Kubota Detachment.18 Yamashita knew that the western side of the Central Plains was wide open south to Bamban, but there
was nothing he either could or wanted to do about it. Like Krueger, he was much more concerned with the situation east and northeast of Lingayen Gulf, although for different reasons.
By 16 January, I Corps had largely overrun the 23rd Division-58th IMB outer line of defenses except in the Mt. Alava-Hill 355 area and on the Cabaruan Hills. Yamashita had not expected to hold these defenses very long in any case. Moreover, the 23rd Division and the 58th IMB controlled such excellent defensive terrain in the Rosario area that Yamashita does not seem to have worried that Sixth Army could or would soon mount a strong drive toward the Baguio anchor of the Shobu Group’s triangular redoubt. However, to guard against a sudden and unexpected breakthrough on his southwestern flank Yamashita, on or about 15 January, did strengthen the road junction area by dispatching south for attachment to the 23rd Division two infantry battalions of the 19th Division. For the rest, the 58th IMB and the 23rd Division were to hold the positions they then had along and on both sides of Route 3 from Palacpalac to Rosario and Damortis until forced back on Baguio.
The defense of the approaches to San Jose worried Yamashita far more. The direction of the I Corps’ advances seem to him to pose a direct and immediate threat to that gateway to the Cagayan Valley. He also feared that American forces were about to drive on San Nicolas at the southern end of the Villa Verde Trail, the best alternate route toward the valley from the south. Still trying to move supplies and troops up Route 5 through San Jose, he could at best take a very anxious view of the 43rd Division’s breakthrough along the 23rd Division’s outer line in the Manoag-Hill 200 area, for the defenses of the approaches to San Jose from this direction were still woefully weak. Some units of the 2nd Tank Division, concentrating in the Lupao area northwest of San Jose, had not yet passed through the latter town. Worse still, the advance echelons of the 105th Division, coming north from the Shimbu area with five battalions of infantry, were still twenty-five to thirty miles south of San Jose as of 15 January. Something had to be done and done quickly if the approaches to San Nicolas and San Jose were to be held much longer.
On 15 January, returning to a once-discarded plan, Yamashita directed the 2nd Tank Division to concentrate in the Tayug area, southwest of San Nicolas. The division would hold the Villa Verde Trail and the Ambayabang River valley, which, lying between the trail on the east and the Agno on the west, provided an approach to Baguio from the south and southeast. The 2nd Tank Division would also assume control over 10th Division elements – principally the 10th Reconnaissance Regiment – already in the Tayug-San Nicolas area. The Shigemi Detachment, still at San Manuel across the Agno west of Tayug, was to move up to Binalonan to cover the displacement of the rest of the 2nd Tank Division. Ultimately, the 2nd Tank Division would withdraw up the Villa Verde Trail to Route 5, re-concentrating along Route 5 to defend the southern approaches to the Bambang anchor of the Shobu defense triangle. The 10th Division, meanwhile, would defend the immediate approaches to San Jose, holding that town until the 105th Division passed through on its way up Route 5. Then
the 10th Division would itself withdraw up Route 5.
Yamashita could not execute these plans, for the 2nd Tank Division reported that it could not carry out the role assigned it. The terrain in the Tayug-San Nicolas area, the division reported, was ill suited to armored operations. Moreover, the division’s terrain reconnaissance parties had concluded that the Villa Verde Trail, the shortest route of withdrawal from the Tayug-San Nicolas region, was impassable for tanks and trucks.
Another event forcing Yamashita to alter his plans provides a sad commentary on the state of Japanese communications. On 17 January the 14th Area Army commander belatedly learned that the 10th Division had never concentrated at San Jose and that it had made no real effort to dispose itself along the entire Tayug–Umingan–Lupao–San Jose defense line for which it was responsible. Lt. Gen. Yasuyuki Okamoto, the division commander, had decided that he did not have sufficient strength to hold the relatively open ground assigned to him. Most of his 39th Infantry was with the Kembu Group, the bulk of the 10th Infantry, greatly understrength, was attached to the 103rd Division for the defense of northern Luzon, and, at least as late as 15 January, he had received no word as to when he might expect the attached Tsuda Detachment to arrive in the San Jose area from the east coast. He had therefore withdrawn most of his troops up Route 5 from San Jose and had started disposing them along the line Yamashita had intended the 105th Division to hold; leaving behind only a reinforced infantry company and two artillery battalions to secure the all-important railhead. Okamoto had directed the 10th Reconnaissance Regiment to remain in the San Nicolas area, and he stationed three or four rifle companies of his 63rd Infantry along the Tayug–Lupao line and in rising ground to the southwest.
Faced with these unexpected problems, Yamashita again had to make sweeping changes in his plans. He decided that the best thing to do was to accept the 10th Division’s redeployment as a fait accompli. He thereupon directed the 2nd Tank Division, which had already started moving toward Tayug, to hold its main strength southeast of Tayug to protect the immediate approaches to San Jose. Leaving the Shigemi Detachment in the San Manuel area, the division would concentrate at Lupao and establish its Ida Detachment – a combat command built upon the 6th Tank Regiment – at Muñoz, on Route 5 about nine miles southwest of San Jose. Thus, both main approaches to the latter town – via Route 8 from the northwest and Route 5 from the southwest – could be held, and forces could be shifted between the two concentrations along a secondary road connecting Lupao and Muñoz.
Yamashita directed the 10th Division to complete defensive preparations in the area where it was already disposing itself; the 105th Division, instructed to speed its northward movement, would drop two of its five first-echelon infantry battalions at San Jose. There the two battalions, as well as the 10th Division detachments at San Jose and in the area to the west, would pass to 2nd Tank Division control. The rest of the 105th Division’s first echelon would continue north up Route 5.
To the northwest, there was one further change. As the Shigemi Detachment prepared to move west from San Manuel to Binalonan in accordance with the earlier plans, it found Sixth Army troops already in the outskirts of the latter Route 3 town. Therefore the combat command decided to fight it out at San Manuel, where it could hold at least one approach to the Villa Verde Trail.
None of the rapid changes in plans for the defense of the San Jose area affected Yamashita’s program for the employment of the 23rd Division and the 58th IMB. These units were already in excellent position to hold the approaches to Baguio, a fact that became increasingly clear to I Corps as it continued to attack toward the Routes 3-11 junction in accordance with Sixth Army’s new plans.