In the fall of 1941 the Japanese Army and Navy High Commands were urgently formulating plans for war against the United States, Great Britain, and the Netherlands in the event that diplomacy failed to achieve a speedy solution of the Pacific crisis. A basic stipulation of these plans was that Japan must attack her primary objectives in the southern area during the coming winter when climatic conditions in Siberia would preclude a possible offensive from the rear by Soviet Russia. Specifically, this meant that the Philippines, Malaya, and the Dutch East Indies must be securely in Japanese hands by the end of February, 1942. Accordingly, an Imperial Conference on September 6 resolved that Japan's decision for war or peace must be taken by mid-October at the latest so that, if it was to be war, final preparations might be made in time to launch hostilities in the first part of November. At the mid-October deadline, however, the nation's leaders were still hesitant to take the fateful plunge, and it was not until November 5 that they definitely decided to go to war in early December if no diplomatic settlement were reached in the interim. The armed forces immediately began girding themselves for battle, and D-day was set at December 8.
There was thus a delay of one month in the opening of hostilities. But in spite of this delay, the war planners did not alter the stipulation that the conquest of all "firstphase" objectives must be completed by the end of the following February. As a consequence the final invasion timetable imposed on the armed forces the stupendous task of occupying the Philippines in only fifty days and securing the whole southern area in ninety days from the start of hostilities. Although this exacting schedule was primarily intended as a precaution against possible Soviet interference, tactical considerations also argued in favor of the Japanese conquering their initial objectives with maximum possible speed. Not only would this facilitate the operations themselves, but it would also reduce the enemy's chances of moving in the reinforcements which would render the task of our expeditionary forces more difficult.
Of the various forms of reinforcement which might be attempted, the first our planners had to consider was the dispatch of additional American air strength. This was judged especially probable if the surprise attack on Pearl Harbor should prove successful, for the United States would then be incapable of sending major fleet strength to Asiatic waters and would be limited largely to air reinforcement. It was estimated, however, that the danger of such reinforcement would be safely averted if we succeeded in occupying our objectives within the time limits set by the war plan.
Particularly heavy responsibility for the successful execution of the invasion schedule rested on the shoulders of our own air forces, which were to spearhead and support the amphibious advance. As the bulk of our carrier strength was assigned to the Pearl Harbor attack, support of the southern invasions would have to be provided mainly by shore-based air. The initial moves against Luzon and Malaya would be supported by planes operating from Formosa and southern French Indochina, and subsequent advances would be carried out by stages, a primary objective of each stage being to secure air bases to which our planes could move forward to support the next stage. In order that this step-by-step process might be completed on schedule, it was decided that the advance southward from Luzon must in no case be delayed even if ground operations on that island were not complete.
In the Philippines, we estimated that our only serious opposition would come from the United States armed forces stationed there, and that they, in all probability, would not be augmented after the outbreak of war. The strength of these forces was estimated as follows:
Ground: Approximately 20,000 regular U. S. Army troops.
Naval: Heavy cruiser Houston, seaplane tender Langley, two light cruisers, 15 destroyers, 15 submarines.
Air: 110 fighters, 40 bombers, 20 scout planes, 10 light seaplanes, and 35 flying boats, for a total of 215 planes. In addition there were believed to be some light aircraft, including trainers of the Philippine Air Force.
To deal with this enemy strength, the following Japanese Army and Navy forces were assigned to the invasion of the Philippines:
Ground: Fourteenth Army, comprising two-and-a- half infantry divisions plus supporting and service troops.
Naval: (a) For direct participation in amphibious operations: Five heavy cruisers, five light cruisers, 29 destroyers, two seaplane tenders, and a large number of small craft of various types, with light carrier Ryujo to be incorporated as circumstances might require.
(b) To operate in nearby waters as a covering force: Two battleships, two heavy cruisers, and nine destroyers under direct command of the theater naval commander.
Air: (a) Army: 5th Air Group, comprising 72 fighters, 27 twin-engined bombers, 54 light bombers, 27 reconnaissance planes, and 12 liaison planes; a total of 192 planes.
(b) Navy: Eleventh Air Fleet main strength, comprising the 21st and 23rd Air Flotillas with 108 Zero fighters, 13 old-type fighters, 81 new-type bombers, 36 old-type bombers, 15 reconnaissance planes, 24 flying boats, and 27 transport planes; for a total of 304 planes. (This was about 60 per cent of Eleventh Air Fleet strength; the remainder was assigned to operations in Southeast Asia.)
As indicated by the respective numbers of Army and Navy aircraft assigned, the major role in the air phase of the Philippines invasion was allotted to the Navy. This was mainly because of the much shorter combat range of Army planes, which had been designed primarily for a continental war against Russia, in which they would operate against Siberian targets from nearby bases in Manchuria. Consequently, Army fighters at this time had a radius of less than 300 miles, while Army bombers carrying a normal bomb load could not cover the round-trip distance between southern Formosa bases and Lingayen Gulf, the principal invasion landing point on Luzon.
Owing to these considerations, it was agreed that in the air offensive planned to precede the initial landings on northern Luzon, Army planes would be responsible only for hitting targets north of the 16th parallel, while Navy air forces would take care of targets south of that line. This meant that the major concentrations of enemy air strength, which the offensive was intended to knock out, lay within the Navy zone. In addition, the naval air forces were charged with combat air and anti-submarine patrol for the invasion convoys at sea, with covering landings on eastern and southern Luzon and Mindanao, and even with support of ground operations on the other islands. Navy and Army planes jointly were to cover the preliminary landings on northern Luzon and the later main landing at Lingayen Gulf (Army planes then to be operating from occupied northern Luzon bases), but Army aircraft alone would be responsible for supporting ground operations on Luzon subsequent to the landings. Quite frankly, it was only in this last-mentioned mission that the Navy air force was counting upon any real contribution by Army air.
With regard to the employment of Philippine air bases earmarked for early seizure, it was agreed that Legaspi, Davao, and Jolo would be used by the Navy, Aparri jointly by Army and Navy, and Vigan and Laoag by Army air forces.
Of special significance in the make-up of the Navy air contingent assigned to the Philippines invasion was the fact that it included virtually every Zero fighter plane which the Navy then possessed except those allocated to the Carrier Striking Force for the attack on Pearl Harbor. This was because the Zero, though designed primarily as a carrier-borne fighter, possessed an exceptionally long range. In 1940 a group of Zero fighters based at Hankow, in central China, had made a record flight in attacking Chungking, 420 miles distant. We thus knew that their action radius was in excess of 420 miles, but there was serious question whether they could operate successfully from shore bases on southern Formosa to support attacks on targets in the Manila area, a full 550 miles away.
The Navy's air operation planners consequently found themselves confronted by an urgent problem for which there appeared to be only two alternative solutions. Either aircraft carriers would have to be employed to serve as a base of operations for the Zeros, or means would have to be found of augmenting the range of these planes so that they could achieve the required 550-mile radius.
Although all six of the Navy's big fleet carriers had been reserved for the vitally important attack on Pearl Harbor, there were three other ships of smaller size which could be used in the Philippines invasion. These were Ryujo, displacing 9,400 tons and carrying 24 planes; Zuiho, of 11,200 tons and a 28-plane capacity; and Kasuga Maru, a converted merchant ship of 17,000 tons, which could carry 23 planes. At first glance employment of these carriers seemed to offer the simplest solution of the problem, but more careful consideration indicated that there were also some serious drawbacks.
In the first place, these three ships were inadequate for the task since, all told, they could not carry more than 75 fighters, and the number which actually could be used for attack operations would be substantially less because some planes would have to be reserved for combat air patrol over the carriers. Furthermore, the ships were so slow that - unless the wind velocity exceeded twenty miles per hour - planes taking off had to run almost the full length of the flight deck. Consequently, at such times, none of these carriers could launch with more than half its planes on deck, and a ship's air group had to be flown off in two divisions.
Much more serious than the deficiencies of the carriers, however, was the difficulty that would be encountered in coordinating the attack operations of Formosa-based bombers with those of carrier-based fighters far off at sea. The respective times of take-off would have to be carefully scheduled in advance to assure that bomber and fighter formations would meet at the proper time and place to attack in concert. Yet the schedule might be completely thrown off by differing weather conditions at the Formosan bases and around the carriers, or by other unforeseen developments affecting either the bombers or the fighters. Last-minute readjustments of plan to meet such contingencies would be hard to effect.
The difficulties of achieving proper air co ordination and generally of maintaining tight control of all the invasion forces would inevitably be increased by the fact that the carrier group would have to observe strict radio silence in order to conceal its whereabouts from the enemy. This weakening of coordination and control was viewed as particularly risky in the Philippines attack because here, owing to the 5½-hour time difference between the Philippines and Hawaii, the Americans would already have been alerted for several hours before our air forces delivered their first blow shortly after daybreak on December 8. Enemy countermeasures therefore had to be considered a definite probability, and to cope with them it was vitally necessary that the tightest possible coordination and control of our forces be maintained. The radio silence under which the carrier group would have to operate, if it were employed, would clearly not be conducive toward this end.
The use of carriers also seemed undesirable from two further standpoints. One was the risk of forewarning the enemy of our intentions prior to the outbreak of hostilities, as the carriers would have to maneuver close to launch Zeros for the opening attack. The other was the loss of efficiency which would result from splitting up our scarce air maintenance personnel to station some on board the carriers.
Because of these considerations, the conclusion of the Navy's air planners was that the second alternative, namely to find means of augmenting the range of the Zeros enough to permit them to operate from shore bases, should be vigorously explored. At the same time, however, the use of carriers could not be definitely abandoned pending some assurance that the efforts to expand the Zeros' range would succeed. Therefore, parallel with these efforts, it was decided that preparations for the eventual employment of carriers should also be carried out.
Evacuating its former base at Hankow in central China, Eleventh Air Fleet concentrated its main strength at Formosan bases early in September, 1941, and began war preparations late the same month. Experimental studies got under way immediately, looking toward extension of the Zero's combat radius. There was also training in such basics as air fighting, strafing land targets, and night formation flying. And when carriers were dispatched to Formosa in mid-October, flight-deck training was begun for the Zero pilots.
It was just about this time that I joined Eleventh Air Fleet headquarters in Takao as a junior staff officer. The Air Fleet's strength in Formosa had nearly tripled by that time as a result of the feeding in of reinforcements. These included a large proportion of fliers insufficiently trained for combat, and virtually none who had had any training in carrier operations. Consequently, with less than two months in which to prepare, the burden of training the fighter pilots so that they could operate either from land bases or from carriers, as eventual circumstances might require, was exceedingly heavy.
This unsatisfactory situation spurred the already strenuous efforts being made to extend the combat range of the Zeros. The Air Fleet Commander, Vice Admiral Nishizo Tsukahara, and his staff, as well as staff officers of the subordinate air flotillas, conferred frequently on this problem, and experts were called in from Air Technical Arsenals to assist. On the lower levels, pilots and maintenance crews likewise worked unremittingly at various means of improving plane performance.
By late October a combat radius of 500 miles had been achieved for the Zeros without any modification in plane engine or equipment. This was accomplished by reducing the engine cruising speed from the previously established 1,850 RPM to 1,650-1,700 RPM with corresponding adjustment of the propeller pitch, and setting the fuel mixture as lean as possible. Thus reduced fuel consumption was achieved without any sacrifice in plane speed. This assured a 500-mile radius, allowing a maximum of fifteen minutes over the target, but it was still fifty miles short of the radius required to operate against objectives in the Manila Area. The further SO-mile extension in combat radius would have to be achieved through pilot skill and discipline to insure constant flight speed, especially in night formation flying. This demanded even more extensive and severe training.
While no one deemed it certain that the required goal could be achieved in time, a final choice between using carriers and not using them could no longer be delayed. Little more than a month remained before D-day, and if our forces were to be ready, we could not continue to train and prepare for both carrier-based and shore-based operations; we must concentrate on one or the other. Accordingly, a staff conference was held early in November to decide the issue. The consensus of the staff was overwhelmingly in favor of unified bomber-fighter operations from shore bases rather than flying the fighters from carriers. Vice Admiral Tsukahara's decision followed the staff view, and an order was issued to limit future training to shore-based operations.
Even with this limitation the training program throughout November was the most rigorous the Air Fleet had ever been through. Every effort was made to bring the flying crews up to peak combat efficiency, and daily fuel consumption rose to such a high level that the supply corps was astonished. Meanwhile, since the use of carriers had been abandoned and further extension of the Zero's range was problematical, other alternatives had to be considered. Tentative plans were made for the occupation on the morning of D-day of Batan Island, midway between Formosa and Luzon, so that our Zeros might make an emergency fueling stop there, if necessary, on their way back from Luzon.
We had known for several years that there was an airfield on Batan Island, but as no recent or detailed information was available concerning it, a secret air reconnaissance was carried out over the island on October 25. Similar reconnaissance of key areas on Luzon was not attempted until November 20, owing to the risk of alerting the enemy to our intentions. Starting on that date, a series of sporadic flights was carried out over a period of four or five days, every possible precaution being taken to guard against enemy discovery of our planes. Final recon naissance missions were flown on December 5 in order to ascertain any changes in the enemy situation just prior to the opening of hostilities.
We recognized that such limited reconnaissance would not provide all the information we needed, but this penalty was readily accepted in preference to the far graver consequences that would have resulted from premature divulgence of our intentions. The prudent attitude of the Navy air force, however, was not everywhere duplicated. For example, the concentration of scores of transport vessels in the south Formosan port of Takao and at Mako, in the Pescadores, was - if the enemy learned of it - an almost unmistakable tip-off that a large-scale amphibious move toward the south impended.
Eleventh Air Fleet nevertheless continued, for its own part, to exercise the utmost caution. Following the first clandestine reconnaissance missions over Luzon, the Air Fleet on November 25 began sending out weather observation planes over the waters flanking the island's east and west coasts with a view to obtaining necessary weather data for the areas which our attack groups would traverse en route to their targets on D-Day. Parallel with all these preparatory activities, detailed planning of the air operations went ahead. The rigorous schedule that had been fixed for the conquest of the Philippines was postulated on the assumption that our forces would win complete control of the air at the outset, and this therefore became our primary mission. As its fulfillment would depend upon the effectiveness of our operations during the first few days of hostilities, it was to these operations that we naturally devoted foremost attention.
Annihilation of the enemy's air strength bad to be the central goal of the initial air offensive, but some members of the Air Fleet staff were dubious that bomber attacks against enemy air bases would contribute much toward this end. Experience in China had shown that amazingly little damage was inflicted even when scores of bombers in tight formation virtually blanketed an enemy airfield with bombs. Consequently, the emphasis in our air tactics had tended to shift to the offensive use of fighters, especially since the Zero fighter had emerged as the dominant factor in Chinese skies in the fall of 1940. The prevalent view thereafter was that bombers should be employed against surface ships and submarines rather than against land air bases, where they were relatively ineffective.
Nevertheless, despite these considerations, the Air Fleet staff finally came to the conclusion that our opening offensive in the Philippines, by both bombers and fighters, should be directed exclusively against the enemy air force. There were three reasons for this decision: First, the enemy's air strength was a much greater menace to our amphibious convoys than his relatively weak surface strength. Second, strafing attacks by our fighters on enemy airfields would be easier and more effective if preceded by bomber attacks to knockout ground defenses. Third, if we attacked early enough on D-day, there might be some chance of gaining tactical surprise and catching enemy planes parked on their fields, in which event concerted attacks might succeed in crippling the enemy air force at a single blow. It was further decided that, in these attacks, the top-priority target at enemy bases would be heavy bombers since they constituted the biggest offensive threat to the invasion forces.
Shortly after these decisions were reached, the aerial reconnaissance of Luzon carried out November 20-25 revealed that several American submarines were tied up alongside a tender in Manila Bay. The undersea craft were considered a worthwhile target despite the earlier decision, for although the enemy's surface strength gave us no real concern, the same was not true of his submarines which might well inflict telling damage on our invasion convoys. Consequently, the plan to send our entire strength against enemy air bases was modified in favor of employing 15-20 per cent of our bombers to attack the submarine concentration in Manila Bay. This modification proved short-lived, however, because the final reconnaissance on December 5 showed that most of the submarines spotted earlier had disappeared and that the few remaining were widely dispersed around the Bay. Under these circumstances, the diversion of part of our bombers to attack them no longer seemed worthwhile, and the original plan was reinstated.
Next to be determined was H-hour, the time for launching the air offensive. Obviously, the closer the time of our initial attack to the Pearl Harbor air strike, the greater would be our chances of achieving surprise with all its attendant advantages. But Japanese planes were to hit Pearl Harbor shortly after sunrise on December 7, Hawaii time, which was several hours before daylight, December 8, in the Philippines. Thus, we had given early consideration to a plan by which our bombers would open hostilities with a night attack in the small hours of December 8, after which a second wave, mostly fighters, would deliver a post-dawn attack, taking advantage of the confusion caused by the bombers. But since experience in China showed that our night bombsight was not sufficiently reliable, a night attack was rejected, and it was determined that H-hour should be the earliest time at which successful bombing results could be expected.
In accordance with this decision, the final plan issued on December 6 for the first attack on Luzon fixed departure time for Eleventh Air Fleet attack groups from Formosan bases at 0230 on December 8. Fifteen minutes after an 0615 sunrise, Nichols Field was to be hit by one force of 54 bombers and 50 fighters from Takao, and Clark Field by another of 54 bombers and 36 fighters from Tainan. These two targets were selected because they were the main concentration points of the enemy's heavy bomber strength. The fighter groups, in addition to knocking down any air opposition, were to execute strafing attacks on both fields as well as on adjacent subsidiary bases. Bombers and fighters not employed in attack operations were assigned to combat air patrol over our Formosan bases and to combat air and anti-submarine patrol for the convoys carrying the northern Luzon advance landing forces. Flying boats were assigned to patrol the waters east of the Philippines.
The overall plan of air operations also called for an attack on Davao, in southern Mindanao, to be executed at dawn on D-day. This mission, however, was assigned to planes of light carrier Ryujo, which it had been decided to employ in support of operations in the southern Philippines. Ryujo was not a powerful carrier but, since no significant enemy air strength was located in the Davao area, she was considered adequate for this mission.
Prior to final adoption, Eleventh Air Fleet's operation plan was carried to Tokyo by special courier and submitted to the Navy High Command for approval. All radio communications of such nature as might risk tipping off the enemy to our intentions were naturally being avoided at this time. Consequently, it was with no little amazement and annoyance - that we shortly received a radio from Imperial General Headquarters in Tokyo, which said:
“Imperial General Headquarters is quite confident of success in jamming the enemy's radio frequencies so that any warning dispatched to the Philippines as a result of the Carrier Striking Force's attack on Hawaii will not get through. Meanwhile, in order to assure the success of the Hawaii attack, it is imperative that Eleventh Air Fleet in Formosa take every precaution to guard against the enemy's learning of our military movements before that attack takes place.”
Here was the highest headquarters instructing us to take precautions when, by sending out a message filled with such ultra-secret information, it was itself guilty of a most flagrant breach of security!
When the operations plan was issued on December 6, our knowledge of the enemy situation, as pieced together from radio and other intelligence and from the reports of our air reconnaissance missions through December 5, was roughly as follows.
1. Most of the enemy surface units and submarines observed in Manila Bay in late November were no longer there. It was estimated that the surface units had moved to southern Philippine waters, while the submarines appeared to be widely scattered. Several submarines had been located by radio to the east of the Philippines and around the Palau Islands, and others were believed to be maneuvering off western Luzon near Lingayen Gulf. Also, on several occasions subsequent to early November, American submarines had been reported to the east and west of Formosa.
2. Most of the enemy's heavy bombers were based on Clark and Nichols, with a few scattered at Nielson, Murphy, Iba, Del Carmen and other minor airfields situated around the two major bases. Starting in mid-November, daily routine air patrols had been carried out over the waters west of Luzon. On December 5 enemy air units in the Philippines had been ordered to a 15-minute stand-by alert.
In addition, our reconnaissance planes had succeeded in obtaining good photographic coverage of Lingayen Gulf, the northern Luzon invasion beaches, and the Bataan Peninsula. The photos of Bataan attracted keen attention as they indicated the existence of extensive fortifications, but no one in our headquarters was capable of interpreting them accurately, and they were immediately sent to Fourteenth Army for more careful study. Actually it was not until our ground forces fought their way through these defenses in the spring of 1942 that their full extent and formidableness were realized.
On December 5 the arduous training program of the past two-and-a-half months came to a close, and the succeeding two days were devoted to overhauling and servicing all planes. On the eve of hostilities the disposition of Eleventh Air Fleet forces was as follows:
Air Base Units
Takao Headquarters, Eleventh Air Fleet
Headquarters, 23rd Air Flotilla
54 medium bombers ("Betty")
50 (approx.) Zero fighters
7 land reconnaissance planes
Tainan Headquarters, 21st Air Flotilla
36 medium bombers ("Nell")
50 (approx.) Zero fighters
8 land reconnaissance planes
Taichu 27 medium bombers ("Betty")
Kagi (Army base) 27 transport planes (for possible use by paratroopers)
During the planning stage there had been a proposal that a part of our strength be shifted to bases on Hainan Island, off the South China coast, in order to avoid possible congestion at Takao and Tainan fields after D-day. This proposal had been rejected for much the same reasons that had prevailed against splitting up our bombers and fighters in order to base the latter on carriers; but, as a precautionary measure, bases at Taihoku and Shinchiku in northern Formosa, and at Karenko, on the east coast, were prepared to accommodate our planes in case congestion should develop at Takao and Tainan.
In addition to the strength enumerated above, Eleventh Air Fleet also had 24 flying boats and 13 old-type fighters ("Claude") which were based on Palau. Army planes which were to participate in the Philippines invasion were based at Heito, Choshu, Kato, and Koshun, all on southern Formosa.
On December 7 orders were issued restricting all Eleventh Air Fleet personnel to their bases, and the men were assembled and told for the first time that Japan would go to war with the United States and its allies the following day. The same afternoon the commanders of the Army and Navy air forces, together with their staffs, met in a joint conference at Navy headquarters in Takao and decided, after studying the weather forecasts for the next day, that the planned air offensive against the Philippines should be initiated as scheduled. Orders to this effect were promptly issued to all subordinate air commands.
As the last hours of peace rapidly ticked away, there must have been many whose thoughts, like my own, were shadowed by misgiving. On seeing the outline for first phase operations I had been struck by its resemblance to a railroad time-table and had wondered if a war could really be fought in this manner, so completely at the will of one side. These doubts had eased somewhat as we proceeded to tackle and solve each difficulty in planning and preparing for our own segment of the operation, but now, when the time for execution was at hand, I was once again assailed by apprehension that our grandiose plan of conquest might be just a castle in the air.
It was too late, however, for futile misgivings. Far to the east our Carrier Striking Force was already making its final run-in toward Oahu. The die of war was cast, and there remained naught but for each man to carry out his assigned role with courage and determination.
Since the attack groups were scheduled to take off at 0230 and cover the greater part of the outward flight in darkness, it was important that the pilots have all possible information about the weather along their line of flight. To obtain this weather data, one scout plane was launched at 2030 and another at 2230 on the 7th. So important was this mission that it was decided to send a staff officer to fly as observer in the second plane, and I was chosen.
The weather that we encountered, while not ideal, was not so bad that the attack would have to be postponed. I gave my opinion, in brief radio reports, that our planes could take off on schedule. Use of the radio was kept to a minimum so as not to alert the enemy, but, nevertheless, there were clear indications that either my plane or the earlier one had been detected. At 2315 our radio monitoring center at Takao overheard Manila sending warnings to Iba and Clark Fields, and at the same time the enemy began jamming the frequencies our weather planes were using.
Just at this critical moment a completely unseasonal mist began to settle over the southern part of Formosa, threatening to upset everything. By midnight the fog was so thick around Tainan that the Air Fleet operations staff was forced to postpone the Clark Field attack from that base. Nevertheless, it was decided to carry out the Nichols Field attack from Takao on schedule. Thirty minutes later, however, the bad weather had reached Takao; the planes there were also grounded. Under these circumstances it was necessary to modify the attack plan for execution as soon as the weather permitted.
Every minute's delay in our attack would render the enemy more prepared. If we still followed our original plan to attack Clark and Nichols Fields, enemy fighter planes based at Iba would be ready for us and could strike the flanks of our squadrons coming and going. Therefore, the attack planned for Nichols Field was diverted to Iba, even though it meant that all of the heavy bomb ers based at Nichols (about half of the enemy's heavy bomber strength in the Philippines) would be left temporarily intact.
The plan was further modified to provide for a diversion. A group of 27 bombers was to be launched early and maneuver close to Iba in order to draw off intercepting fighters based there. After two hours of these tactics, the bombers would join the rest of our striking force in all-out attacks on Iba and Clark Fields just as the intercepting fighters had to land for fuel.
At 0200 the fog over our Formosan bases still showed no sign of clearing, but the entire air striking force was nevertheless alerted to stand by on two-hour notice after 0400. Reports soon began coming in of successful Japanese attacks in other parts of the Pacific. At 0220 came word that the Pearl Harbor Striking Force had attacked the American naval base at Oahu. A United States declaration of war against Japan was reported at 0315. Forty-five minutes later a monitored enemy message from Guam announced attacks on that island. Next came a report that some of our air groups stationed in French Indochina had delivered strikes on Singapore.
Shortly thereafter the heavy weather in Formosa seemed to be clearing, but by 0500 it had again closed in. At Air Fleet Headquarters, anxiety mounted with each passing hour. Finally at 0700 the fog gave way to clearing mist, and the sortie was ordered, far behind schedule. As the projected diversionary feint by our bombers would cause a delay of two additional hours, with the result that the entire attack force would not return to base until after dark, the plan was again altered to eliminate the deception. All attack squadrons were in the air and heading south by 0845, and by 0900 the fog had cleared completely. A radio report announced shortly that Batan Island had been occupied and that its airstrip was available for our use.
My weather plane, its mission completed, had arrived back over Takao at 0600. A heavy overcast seemed to cover all of southern Formosa, and we had to go on to Taichu and land there until the weather cleared. Accordingly, I did not get back to Takao until after the attack squadrons had taken off, but was soon filled in on the changes that had taken place in my absence. Imperial General Headquarters in Tokyo had been making frequent inquiries about developments in Formosa. It must have been a great relief to them to learn that the Philippine strikes had at last been launched.
Our entire operation plan had been based upon seizing the initiative, and here we were six hours behind schedule. What if the enemy got off an attack on Formosa before their own bases were hit? Were we prepared for it? Indeed, our defenses were far from complete. The air raid warning system and antiaircraft defenses were totally inadequate.
Moreover, we had little air strength left since, in addition to the attack groups sent against Luzon, we had dispatched planes to provide anti-submarine patrol for the invasion convoys heading for Aparri and Vigan. A few planes had been held in reserve-some bombers for off-shore patrol and fighters for combat air patrol over our airfields but these were barely enough to compensate for our lack of search radar and would have been ineffective against a determined enemy attack.
Our apprehension over the possibility of an enemy attack on our bases persisted until our squadrons returned from their mission. It was certainly strange that no such attack developed. We were at war with the United States, expecting action at any minute, yet the atmosphere on Formosa remained peaceful and serene almost to the point of unreality.
The sun was lowering to the horizon when the first returning bomber group came into sight, followed by a number of fighter planes. The speedy fighters were behind because they had remained to strafe ground objectives after the slower bombers had completed their work.
As the first plane landed and rolled to a stop, I stood by to listen to the remarks of the crew. Clambering down from their plane, they said in great bewilderment, "Are we really at war?" "We met no opposition." "What is the matter with the enemy?" When similar remarks were heard from other participants in the attack, a fearful suspicion occurred to me. Had the enemy fields been cleared of planes in advance, making our attack completely fruitless? We had frequently experienced this sort of frustration during the war in China, but we had been convinced that our attack on the Philippines would meet with strong opposition.
When the returning crews had reported in greater detail, however, it became apparent that the Jack of opposition was not deliberate. There had been some slight reaction from anti-aircraft guns but no interception by enemy fighters. Even more astonishing was the fact that our fliers had found the enemy's planes lined up on the target fields as if in peacetime. Small wonder that the crews had been bewildered! We were bewildered, too, for it seemed almost as if the enemy did not know that war had started. Could it be that no warnings from Pearl Harbor had yet gotten through to the Philippines?
When action reports were in from all the squadrons, it was apparent that both our fighters and bombers had scored great successes. The reports, of course, had to be very carefully studied to guard against duplication of enemy losses and insure accuracy of the final assessment. Aerial photos taken after the attacks were of limited assistance because there were no pre-attack photos with which to compare them. Indeed, this serious defect in our practice was not corrected until the last year of the Pacific War, and it largely accounts for the constant over-estimation of attack results which so gravely handicapped our operational planning. Perhaps the explanation of this failure lies in the fact that, during the China Incident, the over-estimation of attack results had never produced ill effects to make us more careful. In World War II we awoke to the danger, but only when it was too late.
Our final tally for the first day of war showed enemy losses to be 102 planes. This number included heavily damaged planes as well as those which had been totally destroyed.
Again there was a rash of urgent inquiries from top-level headquarters in Tokyo, especially anxious to learn the outcome of the first attack because they knew that it had been carried out far behind schedule. In answer, our successes as well as our losses only seven Zero fighters and one bomber were duly reported. Within minutes after this message had been filed, the information was being proudly broadcast to the Japanese public.
Since the first day's offensive had departed from the original plan, the attacks scheduled for December 9 also had to be modified. Nichols Field, which was to have been hit the first day but had been dropped in favor of attacking Iba, was now designated the primary target of the second day's offensive. It was decided to open the assault on Nichols with a small-scale night bombing attack, following with heavier strikes after dawn. Accordingly, a force of nine bombers took off around midnight on the 8th. Two planes had to turn back because of engine trouble, but the rest struck Nichols Field at 0303 on the 9th, destroying two hangars and setting another afire.
So far so good, but as dawn neared, our bases were again enveloped in mist. Around 0600 it appeared to be clearing and the main attack groups were readied for takeoff. Once more, however, the fog thickened and the attack had to be finally abandoned. Search flights, attacks on enemy shipping in the waters around Luzon, and all other scheduled missions were cancelled as the foul weather persisted throughout the day. Our air bases, jammed with planes armed and fueled for the offensive, would have been perfect targets for an enemy attack. But the weather which rendered us immobile served also to protect us from attack.
During the 9th our radio intelligence center repeatedly picked up transmissions from American planes searching off the west coast of Luzon, and this activity continued for several days. We surmised that the enemy must be searching for possible invasion convoys and, quite likely, also for aircraft carriers, suspecting that our fighters must have taken off from ships to take part in the Luzon attacks. Such suspicion would have been natural since the enemy, though probably aware that our Zeros had attacked over a distance of 420 miles in China, could hardly have expected that they were capable of flying from Formosa to attack the Philippines and return.
The third day, December 10, brought a drizzling rain which started around 0300. The same weather officer who had forecast good weather for the opening day of hostilities now predicted that the rain would clear shortly and give way to fine flying conditions. The operations staff, though somewhat skeptical, decided to proceed on the basis of this prediction, and made plans to send out all attack groups except our bombers based at Taichu, where the weather was too bad. Time of sortie for the first planes was set at 0830.
Before any planes took off, however, reports were received from the Vigan and Aparri invasion convoys, now standing off the landing beaches, that they had been under attack by American bombers and fighters since 0700. These raids were sporadic and did not inflict serious damage, but they were rather trying for some of the troops and naval crews who were receiving their baptism of fire. At any rate, eighteen Zeros were promptly detached from the attack groups to reinforce the air cover of the advance landing forces.
The attack groups which finally took off were thus somewhat smaller than we had originally planned. One group of 27 bombers and 36 fighters went out to attack Nielson, Murphy and other strips around Nichols Field; eighteen fighters headed for Del Carmen and its satellite bases; and 54 bombers flew to strike at Cavite Naval Base and shipping in Manila Bay. There was undoubtedly some special reason for this departure from the policy of concentrating everything on the destruction of enemy air forces, but I do not now recall what it was.
Despite the weather officer's optimistic forecast, the weather at our bases got worse instead of better after the attack groups took off. By dusk, when the squadrons should have been· returning, visibility had dropped, and the ceiling was down to 100-150 meters. At every field anxiety mounted, and even the sensational news that Eleventh Air Fleet planes based in French Indochina had sunk two British battleships off the coast of the Malay Peninsula failed to lighten our concern.
At last a heartening report came in that most of our fighters had made forced landings on Koshun airfield near the southern tip of Formosa. The headquarters wished to verify this report immediately, and, as communications were bad between that field and Takao, I was ordered to proceed to Koshun by automobile and investigate. Upon arrival I found that nearly all of our Zeros had returned safely. They had for the first time engaged in aerial combat with American fighter planes, mostly P-40s, and had acquitted themselves well. The morale of the pilots was high.
After consolidating the action reports of the fighter pilots at Koshun, I headed back to Takao, arriving about midnight. By then, our bomber squadrons had also returned to their bases and reported on their successes. The combined results showed a total of 104 enemy planes destroyed, of which 43 had been shot down in air combat; direct bomb hits on two destroyers, two submarines, two small transports, and three other surface vessels; and severe damage to fuel dumps and other installations at Cavite Naval Base, where the bomber crews reported several blazing fires.
We did not learn until after the war that one of the most telling blows delivered by our bombers in the Cavite attack was the destruction of the enemy's supply of submarine torpedoes stored there. This severely restricted enemy submarine activity for the remainder of the battle for the Philippines.
The end of operations on December 10 found our planes so widely scattered that it was necessary to reassemble them before we could resume the air offensive. Consequently no attacks were mounted on the 11th, although search missions were flown to the west of Luzon and fighters were sent out to maintain combat air patrol over the northern Luzon anchorages where our advance forces had landed the preceding day.
The primary purpose of these landings was to gain possession of the airfields at Vigan and Aparri, so that they might be used as fighter bases for support of the later main landings on Luzon. The first echelon of Army fighters moved up to Vigan on December 11, and other Army air units advanced to Aparri within the next few days. Eleventh Air Fleet had also planned to move some of its Zeros to the Aparri field, which had been designated for joint use, but our observers with the landing force reported that the field was unfit for the use of our planes, and the plan was dropped. The Navy habitually was opposed to risking operational damage to its planes on poor fields and, in fact, was quite fastidious on this point. The Army, on the contrary, because of the short range of its aircraft, necessarily pursued a policy of moving its air strength forward as far and as rapidly as possible, even though its planes might be jeopardized by poor airfield conditions.
After the one-day interruption of attack operations to permit reassembly of our planes, the air offensive was resumed with a vengeance on December 12. Every one of the enemy's principal air bases on Luzon came under attack by either Navy or Army planes during that day, and more than forty enemy aircraft were shot down or destroyed. Aerial reconnaissance in the late afternoon indicated that the enemy had fewer than fifty operational planes left scattered about the island, and only about thirty ships still remained afloat in Manila Bay, as compared with almost fifty on December 10.
Thus far we had been able to launch attacks only every other day, but on December 13, for a change, the weather continued favorable, permitting the offensive to go on unabated. The attacks carried out during this day administered the coup de grace to the U. S. air force in the Philippines and marked the successful conclusion of the initial air offensive. The next day, back on Formosa, Air Fleet personnel were allowed to leave their bases for the first time since December 7. This relaxation, however, did not extend to mechanics and maintenance men who continued to work double shifts until the 17th to put all planes back in tiptop condition.
Our Zero pilots were now combat tested and had developed confidence that their fighters were superior to any that the enemy had. Some of them had previously fought in China, where most of the opposing fighter planes were Russian-built and flown by Chinese pilots. They had fully anticipated that American fighters would be more formidable adversaries, but during the first week of war they had met and successfully engaged the P-40s, which seemed to be the best fighter planes the enemy had in the Philippines, and had found them inferior to their own Zeros in everything except diving acceleration. Throughout the seventy days of action in this area, the confidence of our fighter pilots continued to grow, nurtured by the absence of effective opposition.
On December 12, two days after the first landings on northern Luzon, a Japanese amphibious force from Palau made another advance landing at Legaspi, on southern Luzon, and quickly seized the airfield there. As at Aparri, the landing strip was found to be in poor condition, but since the Navy alone was responsible for manning this base, nine Eleventh Air Fleet fighters were reluctantly ordered to move up to it on the 14th. Bad field conditions caused two of these planes to overturn in landing, resulting in their destruction, and further misfortune occurred the same day when an enemy P-40 sneaked in to strafe our planes, slightly damaging two more fighters and five bombers (the latter being used for transport) parked on the ground. Our combat air patrol over the base at the time was flying high and did not see the enemy fighter skim in low for his attack.
In spite of these setbacks, Eleventh Air Fleet promptly dispatched additional fighters to Legaspi as replacements and this group played an important part thereafter in assuring Japanese air supremacy over the Philippines. The detachment moved forward again to the island of Jolo, in the Sulu Archipelago, on January 7 and continued its good work which was recognized in a unit citation by our commander-in-chief.
Thus, by December 15, enemy air power in the Philippines had been smashed, and the job had been accomplished almost entirely by planes of Eleventh Air Fleet. Army planes, after moving up to Vigan and Aparri, had carried out one strike on Iba and another on Clark Field, but outside of these two attacks they had left the destruction of the enemy air force to Navy planes since their own primary mission was direct support of ground troops. A consolidation of the battle results achieved by Eleventh Air Fleet during the first week of war in the Philippines follows:
American losses
Aerial combat
Fighters - 63
Bombers - 4
Flying boats - 3
70
Destroyed on ground
Fighters - 59
Bombers and recon 62
Flying boats - 9
130
Japanese losses (from all causes)
Fighters - 23
Bombers - 10
Flying Boats - 1
34
The American losses given in this tabulation were compiled at the time on the basis of a careful evaluation and synthesis of the reports of our air crews, but they are admittedly subject to the over-estimation inherent in such a process.
After December 14 our offensive operations were greatly curtailed by a lack of indicated targets, although many worthwhile targets did, in fact, remain. There were still, for example, enemy cargo ships at 'anchor in Manila Bay, but they were ignored for the most part, since they did not constitute a direct menace to Japanese. operations. Our only concern with these ships was the possibility that they might be used to evacuate enemy troops, and it was felt that we could deal with such an eventuality when and if it arose. Only one strike was made on them (on December 14) by a flight of 26 bombers, and no damage was inflicted because the squadron leader's attack plan was inadequately prepared.
On the other hand, both the Air Fleet headquarters and Combined Fleet were greatly concerned over the whereabouts of enemy warships which had suddenly disappeared from the Manila area. A photographic reconnaissance of central Luzon on December 5 had disclosed the presence of two cruisers, two destroyers, and a submarine in Manila Harbor; a seaplane tender, three destroyers, and six submarines in Cavite Harbor; and several warships in Olongapo Harbor. After hostilities were opened these ships could not be located and it was presumed that they had taken refuge at Iloilo, on the coast of Panay, which was a good central position for strategic defense as it lay outside the radius of Japanese reconnaissance flights. Accordingly we planned a bomber attack on this locality from our Formosan bases, a distance of 750 miles. The strike would have to be made without further information as we could not reconnoiter the area. Furthermore the bombers would be able to take only half their normal bomb load in order to carry the extra fuel required to fly the distance involved.
Combined Fleet Headquarters did not consider this plan adequate. A surprising message received by Eleventh Air Fleet from the Combined Fleet Chief of Staff stated: "Enemy surface craft are believed to be closing in with the intention of blocking our seizure of Davao. Eleventh Air Fleet is advised to dispatch a part of its planes to Palau in anticipation of expected enemy action."
It should be noted that a powerful Japanese surface force, centered around three heavy cruisers, was then stationed at Palau ready to sortie. This group was more than adequate to cope with any makeshift force that the enemy could assemble in the southern Philippines, yet the implication of the Chief of Staff's message was that our air force must run interference to eliminate every possible obstacle before the surface force moved into action. This was the first indication we had of such an attitude on the part of Combined Fleet, and unfortunately it was not the last. But, like it or not, the "advice" of the Chief of Staff had to be honored the same as if it had come from CinC Combined Fleet.
Accordingly we prepared 27 bombers to proceed to Palau on December 17. The movement was actually delayed one day because of a request from the Japanese forces besieging Hong Kong for a bombing of that city and because of damage suffered in a typhoon which hit Formosa on the 17th. The transfer, however, was carried out on the 18th, and the bomber group began operating from Palau the next day.
On the same day that the transfer was effected, the Air Fleet also carried out its own planned attack on Iloilo from Formosa. The bombers found no enemy naval force, however, so the results were negative. Two days later armed bombers searched a broad sector of the southern Philippines and Celebes Sea hoping to find some trace of the vanished U. S. Asiatic Fleet, but these searches, too, proved unavailing.
With the occupation of Davao, the focus of our operations shifted southward. Our flying boat group advanced its base to Davao on the 22nd, and fighter groups followed the next day. This enabled us to intensify our efforts to wipe out the last remnants of enemy air strength in the Philippines, and searches for the elusive enemy surface forces were also stepped up.
On December 25, Jolo was taken and again the field of battle shifted to the south. Although we were supreme in the air, enemy planes continued to make occasional attacks on our newly-won bases both on Jolo and at Davao. Neither of these fields was large enough to accommodate a sufficient number of planes, and in addition the landing strips were extremely poor. That of the Davao field was too soft, and the one at Jolo was set on an incline, which meant that planes had to take off uphill and land downhill regardless of the direction of the wind.
Indeed, few of the air bases which we occupied, not only in the Philippines, but also in Borneo and the Celebes, were in satisfactory condition - a fact that made the planned southward advance of our air squadrons much more difficult than had been anticipated. Although Navy planes did not use it, even Nichols Field, one of the two main enemy bases on Luzon, was found to have some of the roughest airstrips we had ever seen on a big operational base. At Davao and Jolo it took an inordinately long time before the fields were repaired and enlarged sufficiently to permit the bulk of our air squadrons to move forward to them. As an interim measure, small groups of fighter planes were moved up first, following temporary repairs, while the bombers stayed far behind on Formosa until the fields were put in shape for their use.
In the latter part of December, the bomber squadrons were at last ordered to carry out intensive attacks on shipping in Manila Harbor, as well as on the fortifications of Corregidor. These attacks were begun on December 25 and continued for six days, involving a total of more than 300 individual sorties. The results were not commensurate with the effort expended, but direct hits were registered on some thirty merchant vessels and two destroyers. On the day that Manila fell, we observed a great number of vessels that had settled to the bottom with only their superstructures visible above the surface of the water.
By the end of December the missions of the Navy air forces in the Philippines had been fully accomplished, and Eleventh Air Fleet's offensive action was thereafter directed toward the Celebes and the Dutch East Indies. But the complete occupation of the Philippines, which was supposed to be accomplished in fifty days, was actually not realized until the surrender of Bataan and Corregidor on May 7, 1942. Thus, compared with the slow progress of the land forces in this area, it must be conceded that the operations of the naval air forces were remarkably successful.
These air operations were unquestionably small in scale when compared with operations in the European theater and with later air campaigns in the Pacific. Nevertheless, the Navy's shore-based air forces which spearheaded the invasion of the Philippines must be given due credit for the fact that, despite being opposed by approximately equal numbers of American planes at the outset, they never lost the initiative and accomplished their missions with exceedingly small losses both in personnel and aircraft.
In my opinion, it was our Zero fighters which were most responsible for our success. In the Philippines campaign Eleventh Air Fleet functioned like a smooth-running locomotive, and the Zeros were the pistons which propelled it forward. Like the infantryman of land warfare, they moved forward step by step, advancing their bases to keep up with the combat areas, and covering the entire zone of battle with their offensive might.
In his book Strategic Air Power, Stefan T. Possony observed, "Much as the battleship was the queen of the sea, the heavy bomber is the king of the skies." Such, however, was not the case in the Japanese invasion of the Philippines. There our sword, shield, and buckler was the Zero fighter.