Storm Over Leyte

by John Prados

  The Army and Navy ministries regularly coordinated production plans. Officers from both services staffed sections of the Munitions Ministry. Vice Admiral Sakamaki Munetaka led the air materials section of the general affairs bureau. The plan for 1944 would be trashed at the very outset of Japan’s fiscal year (April). The new plan lasted just four months, until superseded by another, even more ambitious one. This plan anticipated a production rate of 5,500 aircraft a month by early 1945. Naturally this involved prioritizing aircraft production, with increased labor and raw materials. Employment at aircraft plants swelled by a third through the year.

  Herculean efforts brought a slight growth in steel production in the summer of 1944. Even though it was not as high as growth in 1943 or early 1944, this level could not be sustained. Tokyo’s stocks of both steel and aluminum were on the brink of precipitous decline. Aluminum supply stabilized only by drawing on strategic reserves. This triggered the tumble. But desperate measures resulted in production, during the three months before the impending battle, of 7,361 aircraft for the armed forces. Peak aircraft production for the entire war occurred that September, when Japanese plants churned out 2,572 warplanes.

  Production had to be matched against losses, however. The September deliveries should be viewed against the loss that month—by the Navy alone—of 773 aircraft. Over the period surveyed previously, between losses in combat and operational ones, the JNAF lost 1,975 planes. Zero fighter production, which stood at 100 in June 1944, reached 115 the next month and 135 in both August and September. It peaked when 145 Zeros left the plants in October. Deliveries of Raiden (“Jack”) and Shiden (“George”) fighters, plus Gekko (“Irving”) night fighters, added about 100 new aircraft on top of that each month. But only in July and August did deliveries outrun losses, and in one month by just a few warplanes. Deliveries of new-type carrier bombers and torpedo planes (“Jill,” “Myrt,” and “Judy”) outpaced losses but, again, only by a few aircraft on average—and the production of twin-engine medium bombers (G4M2 “Betty”) consistently ran far behind casualties.

  Japan’s practice had been to divide effort and raw materials between the armed services. At prevailing percentage rates the Imperial Navy’s share of the new production would have been roughly 4,000 warplanes. Between combat losses and wastage over the same period, the Navy lost just under half as many aircraft as new production added. Bottom line: The admirals would have planes to flesh out their air fleets, but the craft were less sturdy—and there were fewer heavy types like the twin-engine Betty bombers on which the Navy relied.

  Curtailed resources made testing of production aircraft even more important, since the designers were cutting corners and the factories were doing everything to increase production. In these circumstances, the toll of oil imports lost to the Allies became a huge impediment. Testing programs atrophied under the assault of oil scarcity. Ersatz substitutes like gasoline diluted with alcohol, methanol, and other additives were necessary but not good substitutes because they also damaged the engines’ workings. Pine root oil got attention as another substitute. Typically, an engine would be bench tested before installation, the plane would be tested at the factory, and the naval air depot would test it again before accepting delivery. The Navy bench tested engines for nine hours. A test flight would go on for several hours and feature five takeoffs and landings.

  By late 1944, though, protocols were upside down. Bench testing began to be applied randomly—typically to just one of five exemplars, though one source puts it at one in ten. Commander Suzuki Eiichiro, the NGS officer responsible for aircraft maintenance, needed to cut every corner to reduce the burden on the system. The flight from factory to air depot began to be counted as the aircraft’s flight test, and the depots rarely tested a plane on arrival. Commander Muramatsu Tokiwo estimated that aircraft were being accepted with between two and five hours of testing in total.

  Trends already developing at the time of the Solomons campaign were now well established. In general, fighter planes outnumbered strike aircraft. At the Philippines Sea battle, as a result of diligent force building and careful conservation of strength, the Imperial Navy had had a balanced force in its air groups. One more pernicious consequence of the sacrifice of the air groups in the Marianas would be to destroy Japan’s last balanced air force.

  In short, the JNAF became weaker with every passing day. That meant the current production, with all its limitations, would largely determine striking power in the next battle. On July 6, the JNAF ordered a wholesale reorganization of the fleet air arm. A number of the land-based air groups were disbanded. The existing fighter units, as with the carriers, suddenly shrank to a minuscule force. A baker’s dozen of fighter groups became just two. The Americans intercepted the message mandating these massive changes. Unfortunately they did not succeed in deciphering it until October 12.

  • • •

  HASEGAWA KAORU GRADUATED from Etajima in March 1944. Ensign Hasegawa had cottoned to the air corps—every Etajima cadet did a monthlong flight course for familiarization—and he longed to be selected for the JNAF. He got his wish, receiving orders to Kasumigaura for basic flight training. In 1940, due to the pressing need for pilots, training had been accelerated by merging elementary and intermediate courses, with sixty flight hours between them. At that time crews logged hundreds of hours of instructional flight, and just a small percentage of JNAF pilots had had fewer than 500 hours in the air. Now, by 1944, practically no Japanese aircrew had as many as 500 hours. Most of those who did had been moved up to be instructors. Elementary training now came entirely in the classroom. And while advanced combat training used to take the student up to the 100-hour mark, with half that much or more added with a unit before a pilot could fly in combat, by the time Hasegawa moved on to the advanced stage at Usa, in July, he had nothing like that amount of logged air time. By comparison, Ensign Iwasaki Kaneo, an observer and the plane captain of a Zero floatplane (“Jake”), had had the same preliminary training at Tsuchiura, had had his advanced training at Oi, and entered flight service just as Hasegawa began his advanced stage. When Ensign Iwasaki began flying in combat he had 80 hours in the air. Petty Officer Iwata Daisaburo, similarly, spent 80 hours and 10 minutes in flight during his training.

  American pilots typically had more than 400 hours in the air before even moving to a unit. Hasegawa and other JNAF pilots got no more than 80 flight hours—a man was lucky if he reached 100. Lieutenant Commander Shigeki Takeda, a trainer at Kuwa air base a little after this period, had received 160 hours of instructional flying in his preliminary flight training, then 170 hours with a combat unit before entering full duty.

  “Kate” torpedo bombers (B5N2 or Type 97) were the usual training aircraft. But with the increasing demands of the front in the middle of the war, the JNAF often skipped aircrew past the advanced training to the combat units. That backfired in 1944, since the lumbering 235 mph Kate bore no resemblance to new aircraft—fighters like the J2M “Jack” (371 mph), N1K2-J “George” (363 mph), and A7M “Sam” (357 mph); or bombers like the B6N2 “Jill” (289 mph) and the D4Y1 “Judy” (350 mph)—which were now in the units. Airmen needed advanced training for the new-generation aircraft.

  More than that, the growing superiority of Allied airpower made night attack—when just a fraction of Allied aircraft could fly—the most desirable tactic. Night attack required the most practice. Yet—because of fuel—in the spring of 1944 JNAF began imposing restrictions on flying hours for trainees. Until the Marianas campaign, the training command had few restrictions on its use of aviation gasoline. By that summer, however, the NGS began to ration aviation gas, allocating a certain amount for training.

  This was the new JNAF. Japan had been defeated in the Marianas. There were 4,000 prospective pilots and observers in training in August 1944, the high point for the war. The extensive training of the prewar and early war periods had been telescoped and then further restricted. The yearlong offi
cer course and eight-month enlisted program were both cut by two months. Fuchida Mitsuo called this the “Red Dragon” training. In addition to the shortened training regimens, age requirements to serve as a flier were dropped by two years. A fourteen-year-old “young pioneer” could enlist, spend a couple of years at a special school, then enter JNAF training. Training for ground crews shortened from a year to just four months.

  Captain Mieno Takeshi, director of training at naval air headquarters, hated the practice, but reality forced it upon him. Combined Fleet chose how to distribute gasoline among its field and training commands. Commander Terai Yoshimori saw the gasoline situation as “acute” by that autumn. Early the next year Captain Mieno would be forced to resort to limiting the monthly flight hours permitted every training plane. Trainers had also slashed washout rates—from 40 percent before Pearl Harbor to just about 5 percent by 1945. The net impact pained Mieno: Less thoroughly tested—but more dangerous—aircraft were going to units consisting of marginally trained aircrew, in a situation in which JNAF’s raw striking power had diminished.

  Ensign Hasegawa knew nothing of these calculations. He worried the war would end before he could get into it. Hasegawa also reached the fatalistic conclusion—perfectly rational, given the JNAF situation—that he would die in the air. At least the Kasumigaura trainers had an internationalist orientation and a sense of humor. Every weekend they would have Western movies shown in the auditorium. One Saturday the duty officer’s order read, “If we are to win the war, we must first know our enemy. Today, the movie One Hundred Men and a Girl will be shown. Attack the enemy!”

  • • •

  THE PARAMOUNT CHALLENGE for the Imperial Navy would be to reconstitute the carrier air groups decimated in the Marianas. Though the fleet had lost two big flattops there, more were now coming on line. The Amagi and Unryu, full-size carriers, joined the fleet in early August. A sister ship, the Katsuragi, still fitting out, would become available in a couple more months. Two Japanese battleships, the Ise and Hyuga, had been converting to hybrid aircraft carriers and were in sea trials. They could operate floatplane bombers. The behemoth Shinano, transformed from a huge Yamato-class battleship, would be launched at the same time Katsuragi joined the fleet. Half a dozen additional carriers of various sizes were under construction, with two more than 80 percent complete.

  On August 10, a reorganization revamped the carrier force. Carrier Division 1, survivors of the Battle of the Philippine Sea, comprised fleet carrier Zuikaku—the only vessel remaining from those that had struck Pearl Harbor—the converted light carriers Chitose and Chiyoda, and the light carrier Zuiho. Equipping those ships alone—they constituted Naval Air Group 601—meant qualifying pilots for 174 planes. The group would include a unit of Zero fighters, one of Zero fighter-bombers, and one combining torpedo planes and dive-bombers. The re-formed force would not be ready until the end of 1944. The loss of ships at the Battle of the Philippine Sea brought the dissolution of another full air group, which could not be re-formed until new-construction aircraft carriers joined the fleet. The new carriers soon to join the fleet brought a requirement for 250 additional carrier aircraft. Once re-created they would be Air Group 653. The hybrid battleships, in Carrier Division 3, needed 44 seaplanes. With added fighters they became Air Group 654.

  For the short term there would be no new carrier air groups. A Mobile Fleet plan issued on September 10 envisioned that pilots might be ready for daytime carrier landings by mid-October. In general, crews were not considered for shipboard service until they had at least 500 flight hours, but for Japan at this crucial passage, the rule was waived. Since the vast majority of pilots were enlisted sailors, and those ranks were filled with fresh-faced newcomers, Captain Mieno could see no alternative. So for the interim, Carrier Division 1 would have a skeleton group, with the expectation that sufficiently experienced pilots would become available around January 1945, even though current skill levels were so tenuous the fleet did not trust its pilots to fly out to their ships when the carriers sailed. Instead, the planes would be loaded aboard by crane, before the vessels sailed to battle.

  DISPELLING THE FOG OF WAR

  American spies watched all of this.

  The Estimates Section at JICPOA put out regular tabulations of Japanese strength of all kinds. Its air analysis unit became so important it was split off into the Enemy Air Section. Their figures were incorporated into the Estimates Section’s tabulations, then forwarded to fleet intelligence officer Captain Layton, who wrote commentaries and sent each package to Nimitz and other senior commanders. The intel provided guided their decisions.

  JICPOA had a crackerjack analyst for the Japanese air estimates on its team—Lieutenant Richard W. “Dick” Emory—who tracked the radio call signs of the JNAF air fleets, flotillas, and naval air groups. With his legal mind and Harvard-inculcated precision, Emory accumulated pieces of string until he could compile a Japanese air order of battle. One of Emory’s signal achievements came in February 1944 when he was able to estimate the pattern of JNAF air searches out of the Combined Fleet base at Truk, entirely by reasoning from scattered data. Using that intel, the U.S. carrier fleet made a raid on the Japanese base that would have devastated the Combined Fleet had it not already departed. (The Japanese took warning from a U.S. photo recon flight that had scouted the base.)

  Other Allied commands had their own air intelligence analysts, duplicating the work being done at Pearl Harbor. Washington split this work up among different units, two of which were the Office of Naval Intelligence’s (ONI) Far East Division order of battle unit, known as OP-16, and a combat intelligence branch working directly for Admiral King, housed in OP-20-G, which had an order of battle unit called F-22 under Commander William J. Sebald. These two units regularly exchanged information—OP-16’s air intelligence branch answered questions and compiled studies at Sebald’s request, and F-22 published Japanese strength estimates.

  Throughout this period, radio intercepts were the raw material for the strength tabulations of the Japanese. The Americans were lucky in that JNAF administrators required each base to file a daily activities report, messages that inadvertently furnished the Allies with a window into the Imperial Navy’s air arm. In addition, over time a certain number of prisoners and documents were captured. The interrogations and translations afforded new insights. In time, the material filled in the blanks, enabling Allied intelligence to project the numbers of frontline and reserve aircraft, the ratio of pilots to cockpits, standards for staffing, and so on.

  Down under, General MacArthur’s Southwest Pacific command had the Seventh Fleet and, under it, the Seventh Fleet Intelligence Center (SEFIC). Captain Arthur H. McCollum, who had headed the Far East Division of ONI, went to Australia late in 1943 to survey MacArthur’s naval intelligence needs. While there McCollum would be shanghaied as fleet intelligence officer and SEFIC chief. He had eight officers in his Estimates Section and six in Enemy Information—but twenty-two in Translation and four more interrogators. Fleet Radio Unit Melbourne (FRUMEL) would be MacArthur’s counterpart to FRUPAC at Pearl Harbor.

  MacArthur had something else that was lacking at Pearl Harbor. This was the Allied Translator and Interpreter Section (ATIS), a specialized unit for language translation of both captured documents and prisoner interviews. Many of its staff were Nisei—Japanese-Americans—who fought for the country even while their families were being imprisoned in U.S. internment camps. The Nisei were absolutely indispensable to the war effort. They represented both the largest pool of translators and the most qualified linguists.

  Washington and Pearl Harbor clashed over the Japanese air estimates, specifically over the role of the First Air Fleet. Captain Henry Smith-Hutton had sent Commander Sebald, who had charge of the air reporting, to JICPOA to have it out directly. Jasper Holmes introduced Sebald to his resident air expert, Dick Emory. The two mulled over the intelligence. In February 1944, Sebald circulated a paper correctly iden
tifying Japanese units in the First Air Fleet and discussing its purpose.

  Despite this effort, aircraft estimates continued to show wide discrepancies. The JICPOA assessments were higher, and they increased considerably that spring. The main reason for this lay in Lieutenant Emory’s belief that air groups the Japanese used to train crews could be flown for defense if the need arose.

  These arguments illustrate the difficulty of deriving meaningful estimates of JNAF strength. In practice, a projection involved some tabulation of Japan’s aircraft production, its combat losses, the loss of aircraft in accidents, crashes, and so on (termed “operational losses”), and an evaluation of planes already in units. All of these were soft figures. Allied intelligence had no hard data on Japan’s factories or operational losses, had only its own pilot claims for combat losses, and had just the scattered data for frontline air units, which had been photographed (or had been reported in Ultra message traffic) for unit strength. Pilot claims were famously known to be exaggerated, and both F-22 and JICPOA made conscious efforts to deflate them. Comparison of Japanese data provided after the war with U.S. intelligence estimates from 1944 shows the intel consistently underestimated Japanese aircraft production as well as operational losses, while still overestimating combat losses.

  Late in 1944 U.S. intelligence began to devote special attention to Japanese aircraft production. The first report in this series complained of the scarcity of Ultra data, and not long afterward an Army officer who had stopped by at JICPOA on his way to join MacArthur’s intelligence staff found a whole series of “consignment” messages sitting in the Ultra files. These intercepts recorded the Imperial Navy’s acceptance of new warplanes and what units the aircraft would join. The consignment messages furnished a direct measure of Japanese production and put the aircraft estimates on a new basis.