by John Prados
Night-attack tactics were also a plus for Kusaka. Training this force had been difficult, for many units had had to practice while keeping up standard operating routines. The 751st Air Group was a good example. A storied unit, with battle honors for sinking the British capital ships Repulse and Prince of Wales; and a mainstay of the Philippine, East Indies, and China campaigns (under its previous identity as the Kanoya Air Group), the 751st had reunited at Rabaul in September 1942. Thereafter it had participated in the Henderson Field bombing as well as the raids at the time of Santa Cruz. The night missions had actually sharpened aviators’ skills, as the 751st demonstrated when it helped sink the American cruiser Chicago in January.
Completion of the air base at Munda created another new bastion, soon protected by eighteen heavy flak guns, twenty of 40mm caliber, and fifty quick-firing 25mm pieces by the count of Q-bush’s photo interpreters. They were well protected, their worst problem ammunition supply. Through the first half of 1943 there were only a couple hundred casualties among the flak crews, which, considering the weight of Allied attacks, amounted to very little. Repeated Allied naval bombardments damaged Munda’s runway, but it was never out of action for long. Halsey’s neutralization campaign convinced Kusaka not to station Navy planes at Munda, yet it remained vital as a bolt-hole for damaged aircraft or those low on fuel. By mid-1943 there were 12,000 Japanese at Munda, with several months of food and one month of ammunition supplies.
Gloomier aspects were also apparent. The Japanese Naval Air Force had been shorn of hundreds of its best pilots and crews. While the total number of aircrew had grown since Pearl Harbor, the percentage of less experienced fliers increased rapidly, and the Navy had no system for regular rotation of flying personnel. Men flew until they were shot down, they were assigned to another air group, or their units redeployed. The 751st Air Group, to take one case, had been so sharply reduced that after eight months in action it would be withdrawn to Tinian for retraining and reinforcement. Some 150 airmen were lost in just the first four months of 1943. Captain Sato Naohiro brought the group back to Rabaul in August. By then only a dozen of Sato’s crews were qualified for night attack. For the remainder of the campaign the 751st flew out of Vunakanau and Buka. Having returned at full strength—fifty-two aircraft—the unit would be given another fifty replacements, and in November it absorbed fifteen Bettys from the 702nd Group, which had to be disbanded. Yet when the 751st left for Tinian again it possessed just twenty planes—and eight of them were flyable but not capable of combat. In short, the air group had lost nearly a hundred warplanes. At that point officer pilots were nearly extinct in Sato’s group—two of his squadrons (hikobutai) were led by junior lieutenants and one by an ensign. The Solomons arena burned through JNAF units.
Captain Sato’s headaches regarding mechanics matched his problem with aircrews. The group had two maintenance units, each responsible for servicing the planes of a pair of 751st Group flying squadrons. With losses, one of the maintenance outfits had to be converted into a training unit. Melding Sato’s formation with the 702nd Air Group actually proved advantageous, for it brought a new gang of mechanics to replace the men reassigned as instructors.
Individual pilots were funneled in to replace losses, but reassignment usually happened in conjunction with debilitating sickness or unit withdrawal. One example would be Warrant Officer Shimakawa Masaki of the 204th Group, so badly afflicted with malaria that he was put on a hospital ship that departed in March. Another was ace Nishizawa, sent home from the 253rd Air Group in late 1943 to become a pilot instructor. A third was Warrant Officer Ohara Ryoji of the 204th, the so-called “Killer of Rabaul.” Air officer Nomura believed that an inability to keep up the level of experienced fliers and maintenance men, shortfalls in aircraft production, and the quality of Allied planes, were key reasons for high loss rates.
Averages tell the story. The percentage of pilots rated expert, with more than 600 hours in the air, had declined by a quarter. Worse, around the beginning of 1943, the JNAF reached the fifty-fifty point in terms of experts versus less experienced fliers with 300 to 600 air hours. By February those with fewer air hours exceeded expert airmen for the first time, and within a matter of months the Navy would begin sending pilots into battle with just 200 to 300 air hours. In February there were 104 combat losses but 161 aircraft destroyed by accident or mishap. By spring the ratio of operational to combat losses would rise to two to one, a rate that improved only occasionally and would often be exceeded. Despite the experienced airmen reassigned as instructors, larger numbers of trainees meant less personal attention, while diminishing supplies of aviation gas reduced training hours in the air.
Commander Ohmae, who had been at Rabaul since the onset of the Solomons campaign, estimated that barely 15 percent of the expert pilots who had flown against the Americans still manned their cockpits. The 582nd Air Group, though up to strength, had just four fighter pilots left from its original complement. By July the 204th Air Group had not a single officer pilot. In mid-July the 201st Air Group, a Zero fighter unit, arrived in Rabaul. Commander Nakano Chujiro, its boss, assessed his pilots as eight experienced, twenty competent, and twenty-four novices. Fresh-faced young fliers developed a fear of Allied interceptors, especially the F-6F Hellcats, but even of the trusty older Wildcats. An American intelligence study prepared in October 1943 captures this well:
They made glaring tactical mistakes, unnecessarily exposed themselves to gunfire, got separated and lost mutual support, and at times seemed to be completely bewildered. Both bomber and fighter pilots ceased to display the aggressiveness that marked their earlier combat. Bombers ceased to penetrate to their targets in the face of heavy fire, as they had formerly done; they jettisoned bombs, attacked outlying destroyers, gave up attempts on massed transports in the center of a formation. Fighters broke off their attacks on Allied heavy and medium bombers before getting within effective range, and often showed a marked distaste for close-in combat with Allied fighters.
On the other hand, a U.S. intelligence commentary a few months later observed that between February and June 1943 there had been a partial resurgence of high-quality performance among JNAF fliers. But in June alone, the 204th Group lost five of its most experienced prewar pilots.
The crews resigned themselves to fighting at a disadvantage yet with determination.
Early in the year there had been a daylight air raid on Rabaul, an ominous sign. But only a dozen B-17s participated. That was a big strike. General Kenney’s air force was stationed on primitive bases—like the Japanese themselves—with gaping spare parts shortages and the challenges of flying in the tropical climate. Bomb squadrons that typically possessed twelve aircraft had trouble keeping more than seven in flying shape. These were the units that went against Rabaul. “We’d go in individually,” recalled Lloyd Boren, a bombardier with the 19th Bomb Group. “We only flew in formation twice.” On many nights a few planes circled above the base, occasionally dropping a bomb, utilizing intruder tactics identical to those of “Washing Machine Charlie” over Cactus. Kenney’s airmen made more than twice as many sorties against the fortress in January 1943 than in the previous month, though their effort overall (127 flights) remained at a low level, fewer in February (110 sorties)—and these would be high points until the summer. A couple of larger night raids in February inaugurated the use of incendiary bombs. One Japanese airman at Vunakanau thought the incendiaries were like lightning bolts.
Meanwhile the Japanese aircraft industry confronted major headaches in getting its own innovations through engineering development into production. Meeting specifications required more powerful aircraft engines, and the Japanese had trouble there. Engine problems delayed both the J2M (“Jack”) and the Zero follow-on A7M (“Sam”) fighters. The Sam failed to perform with its first engine and had to await a new one, delaying the program two whole years. Tooling the manufacturing plants to produce new planes posed other difficulties. Production of the “Judy” (D4Y), a new carrier sco
ut plane, remained so sluggish that during the Guadalcanal battles the Navy’s carriers had only small detachments of these craft. The Jack was accepted for production in October 1942, but by April 1943 only fourteen had been delivered. Over the next year the plants manufactured just 141 more of these planes. With the N1K1-J (“George”) the factories turned out only seventy aircraft by the end of 1943. Japanese predilection for lightweight designs caused additional problems. The Judy had been designed as a carrier bomber but became a scout when it was revealed that carrying bombs damaged aircraft structural components. The “Jill” (B6N2), the next alternative, was revealed to have understrength arresting gear and failed its carrier landing tests aboard the Zuikaku and Ryuho in early 1943. Redesign retarded production. Deliveries by midyear numbered 133. Accidents and teething problems with the “hot” Jack fighter that summer required further design modifications and triggered more factory delays. During the time of decision in the Solomons, the new aircraft hardly made an impact. The Imperial Navy would be obliged to fight with the weapons at hand.
Such problems did not go unnoticed at the highest level. Emperor Hirohito, a scientific adept, took an interest in aircraft and the aviation industry. Lord Kido, the privy counselor, records that at the end of March the emperor spent much of an unusually long audience with him ruminating on the setbacks in the Solomons. Heavy losses in aircraft especially concerned him. From a Tokyo perspective the future seemed bleak.
Given the fragility of naval aircraft—Army planes were actually better armored and protected—and the steadily increasing numbers of new-generation Allied fighters, the trends were distressing. At the point when the Allies occupied the Russells, Admiral Kusaka’s air strength remained respectable, at 200 serviceable planes, though the Guadalcanal withdrawal cost about fifty effective aircraft. The JNAF had become inferior in both numbers and quality.
Combined Fleet chief of staff Ugaki complained incessantly to his diary of Japanese air forces found wanting. At Truk, where the fleet flagship moored, the picture was actually brighter than nearer the front. The deployment of the night-attack force bombers seemed a plus, quickly rewarded by destruction of the Chicago. But at Rabaul the high losses of experienced airmen and the poor aircraft upkeep, leading to low serviceability rates, were petrifying. It was symptomatic of this situation that some of the unit commanders and best crews in the night-attack force had perished in its first engagement. On the other hand, Allied bombing of Rabaul declined after February—to a low of just nine sorties in April. Another good sign, in May, would be the first JNAF night fighters, twin-engine Irvings converted from scouts. Commander Kozono Yasuna of the 251st Air Group suggested replacing the observer’s position in the cockpit with upward-firing 20mm cannon. The Irvings represented the first aerial opposition to the Allies’ nocturnal bomber raids, which returned to a high level in June with 141 sorties dropping 284 tons of ordnance. Ensign Kudo Shigetoshi would score the first B-17 kill with an Irving on the night of May 21. A half dozen more victories followed before August, when Admiral Kusaka gave Kudo a sword.
The Japanese high command understood the necessity to regain control of the air. No matter the weakness of the forces, this was a prerequisite to success. Admiral Nagano exhorted the Combined Fleet both privately and through Imperial Headquarters. The November IGHQ directive that underlay base construction at Munda and Kolombangara had dictated special attention to strengthening air defenses. A month later, setting operational policy for New Guinea, Imperial Headquarters again underlined the need for aerial strength. The orders that mandated the KE Operation provided for Navy and Army air forces to “display their all-out joint might.” Other activities should be conducted under this air umbrella. The Navy was to concern itself especially with the Solomons, the Army with New Guinea. Admiral Nagano hinted to the emperor that Munda would be abandoned if the base became endangered. When they next met, on January 26, Hirohito opposed that course, and the naval command backed down. Munda would be held and New Guinea contested. Recognizing the growing threat of General MacArthur’s offensive, the high command diverted to Papua, where Japanese positions were threatened, the troops earmarked for the next, now forgotten, Guadalcanal offensive.
At Rabaul the high command’s intentions boiled down to collaboration between Admiral Kusaka and General Imamura on a major reinforcement of New Guinea, with the bulk of the 51st Infantry Division to be sent there in a troop convoy at the end of February. Kusaka and Imamura believed MacArthur’s forces would need to catch their breath after their exertions at Buna, so the opportunity seemed to be offered for this maneuver. Admiral Mikawa laid down detailed plans for the scheme, called Operation 81. Eight transports would be stuffed with men and supplies, escorted by an equal number of destroyers under Rear Admiral Kimura Masatomi. Because a convoy to Lae had gone without incident in January, Mikawa felt this could succeed also. He had no illusions that the convoy would emerge unscathed—at their speed of seven knots the transports would be within attack range for as long as two days—but Guadalcanal experience suggested that at worst half the 7,000 troops would reach their destination, doubling the Lae garrison even at that level of losses. The risk seemed worth taking, given the stakes involved.
Mikawa made careful arrangements with Eleventh Air Fleet. For a few days prior to the convoy there would be neutralization attacks on Allied air bases around Port Moresby, Buna and Rabi. With Army planes participating and the arrival of the 25th Air Flotilla, as many as 200 fighters would take turns patrolling above the ships. Desperate for sustenance, the Japanese were determined to succeed. The first bad omen came when poor weather and overconfidence combined to nullify the precursor raids. Reconnaissance flights either were canceled or returned few results. The Japanese would have scant knowledge of the opposition. No one realized the great danger that lay ahead.
SLAUGHTER IN THE BISMARCK SEA
As with the bloody tales of the Guadalcanal convoys, the story of the Lae transport fleet again demonstrated the vulnerability of slow ships to mass air attack. This Allied triumph, with a minor assist from the codebreakers, was the product of energetic SOWESPAC airmen both innovating new techniques and executing their missions. As early as February 19, General Willoughby’s G-2 warned of probable enemy attempts to reinforce Lae. Two days before the Japanese convoy sailed, Ultra had enough of an inkling to issue a warning. While the picture remained fuzzy—the codebreakers were not sure of the convoy’s size, its escort, or whether the Japanese intended prior or concurrent “mouse” missions—Allied intelligence was certain that transports were involved, that their destination was Lae, and they projected a date of arrival. This was enough to alert the Fifth Air Force to search with special care, and it gave General Kenney a chance to marshal his strike planes for the appointed days. Though a number of worn-out units were resting in Australia, Kenney put together 129 bombers and 207 fighters for the battle. The Australians contributed fifty of those planes. Kenney’s bomber command even planned for contingencies, creating three different options depending on which way the Japanese turned as they approached New Guinea.
Rear Admiral Kimura, an experienced officer, had been in some tight spots already. He had had an important role in Kondo’s naval battles off Cactus, and was another of those who had witnessed the Hornet ablaze at Santa Cruz. Kimura was old-school, sporting a splendid mustache, and had risen through the ranks as a mine and torpedo expert, just recently promoted to flag rank. His experience might have helped, except that General Kenney had an enormous strike force, plus the benefit of a newly innovated technique called “skip bombing.” With this method an airplane would toss its bombs at an enemy vessel, like skipping a rock across a pond, resulting in a very flat trajectory and minimizing the ability of a ship to react. Bombs were armed with delayed-action fuses to permit the skip action to take effect. Kenney also modified his bombers with rigs of eight forward-firing machine guns to strafe as they made their attack runs. The Allies would suppress the flak gunners by having some fighters stra
fe alongside the bombers and by simultaneous attacks from low and medium altitude.
Familiarity with standard torpedo tactics would not help Admiral Kimura here, for turning into or directly away from an aircraft using skip bombing actually increased the target aspect. The old salt also would be poorly served by Japanese air cover. While the JNAF and the recently created Fourth Air Army had plenty of fighters to protect a westerly run to New Guinea, their bases were under SOWESPAC attack, and the nearest airfield on New Britain, at Gasmata, could not handle masses of aircraft. The headache of Japanese aircraft flying at extreme range repeated. The Army interceptors had less endurance than JNAF Zeroes. Some forty Navy and sixty Army fighters would patrol. Lieutenant Sato Masao brought the fighters of his Zuiho air group to Kavieng to be available for the operation. Despite preparations, Kusaka’s Eleventh Air Fleet found itself hard-pressed to keep as many as forty fighters orbiting the convoy. They would be no match for Kenney’s Fifth Air Force. Admiral Kimura steamed into a trap.
Kimura set the time of departure from Rabaul shortly before midnight of February 27. The admiral flew his flag in destroyer Shirayuki. Senior Army commanders also sailed in the tin cans, General Adachi Hatazo of the Eighteenth Army in the Tokitsukaze, and General Nakano Hidemitsu in the Yukikaze. The first day passed peacefully, a deceptive prelude to hell. Admiral Weather helped the Japanese, with a storm front above New Britain—gale-force winds, recurrent rain, plenty of mist. But late on March 1, one of Kenney’s snoopers saw the Japanese convoy for the first time. SOWESPAC tried an immediate attack with some B-17s, but the weather closed in and they could not locate Kimura. The next morning Kenney had his scouts deliberately looking and found the convoy, leading to a bombing late that day by B-24 Liberators. Kusaka’s land-based Zeroes had some success distracting the bombers, but one transport, struck aft by a heavy bomb, settled and sank. Kimura’s destroyers hovered next to her and rescued many of the embarked soldiers and crew. That night Australian PBY Catalinas followed the convoy and made harassing attacks but obtained no results. Two of Kimura’s destroyers dashed ahead to land their Army troops, including General Nakano, at Lae. The warships rejoined the convoy early in the morning of March 3.
