by John Prados
The warplanes themselves were worn out and beset with problems. Maintenance crews could hardly keep up with the damage. Spare parts were scarce and being run into Rabaul aboard destroyers. On paper the Eleventh Air Fleet was supremely powerful, with 144 Betty medium bombers, 96 Val dive-bombers, 24 Kate torpedo planes, an equal number of patrol aircraft, and 312 fighters, an aggregate of 608 aircraft. Yet Admiral Kusaka’s serviceable strength amounted to barely 200 airplanes. Two-thirds of his flying machines were useful only as a boneyard to scavenge for parts to keep others in the air.
Commander Okumiya presently departed to help reorganize the Carrier Division 2 air groups. In the Solomons the fight went on. Heavy fighting over the Buin complex took place almost daily. By late July AIRSOLS was striking with eighty bombers at a time accompanied by more than a hundred fighters. In mid-September JNAF interceptors had to repel five air raids in a single day. The cumulative effects told. “Prior to the beginning of 1943,” noted Chief Petty Officer Iwamoto Tetsuzo, Rabaul’s top ace, “we still had hope and fought fiercely. But now we fought to uphold our honor…. We believed that we were expendable, that we were all going to die. There was no hope of survival—no one cared anymore.” In a postwar study for the Occupation, former Imperial Navy officers, considering morale at this stage, chose to compare mid-1943 with that fall in order to set a baseline permitting them to conclude that until this point morale had remained stable.
Equally problematic, losses among the dive-bomber and torpedo plane units, combined with low production, condemned the JNAF to a critical shortage of striking power. That spring, attack formations like those in Yamamoto’s big offensive were already being sent off with two to four fighters per bomber. By the fall, ratios of fighters to attack planes as low as two to one were unheard-of. Five or more fighters per bomber had become typical. Partly attributable to JNAF desperation to penetrate the curtains of Allied air patrols, partly to simple numbers of available aircraft, the trend took hold. Since the Zero had yet to evolve any significant fighter-bomber capacity, this deficit in Japanese attack capability was even greater than raw aircraft numbers suggest.
Not least among Kusaka Jinichi’s worries was keeping his excitable cousin Ryunosuke in check. It was the other Kusaka who was the aviation expert, and he watched with increasing concern as the Eleventh Air Fleet proved completely unable to blunt Halsey’s advance. The Rabaul command also faced continuing demands for action in New Guinea. Kusaka Ryunosuke coped by focusing Sakamaki’s 26th Air Flotilla on the Solomons while the Rabaul-based 25th concentrated on New Guinea. The Japanese Navy was serious about New Guinea, continuing raids there even as Rabaul came under siege. Rear Admiral Ueno Keizo’s 25th Air Flotilla attacked Buna, Lae, Oro Bay, Finschhafen, Woodlark, and Goodenough islands, and other targets. Finschhafen, just occupied by Australian troops, became a focal point, struck more than a half dozen times. The last significant offensive missions in the Solomons were against Munda and Vella Lavella at the end of September and beginning of October.
But the Allies compelled Japanese attention to the Solomons. Bull Halsey’s air commanders, Rear Admiral Marc A. Mitscher of AIRSOLS and Brigadier General Nathan F. Twining of the Thirteenth Air Force, gave the enemy no respite. The proportion of Japanese supplies sunk in the Solomons, which had hovered at one-tenth the previous year, was up to a quarter. AIRSOLS carried out 158 attacks during October for a total of 3,259 sorties. Twining’s Army air force was right behind. In that month the Army airmen flew 684 bomber sorties and 1,659 with fighters. The recently formed Thirteenth, though working through teething troubles, was emerging as a powerful force. Through the end of October Twining’s airmen were credited with sinking nearly 20,000 tons of shipping, with a few more vessels rated as “probable,” and to have damaged another 60,000 tons. Admiral Nimitz would recall Mitscher to lead Pacific Fleet carriers, with Twining left in the top command. AIRSOLS and the Thirteenth Air Force made the combination of Army, Navy, and Marine aviation that finally turned Rabaul into a smoking ruin.
Before that happened, the South Pacific airmen advanced the Allied aerial curtain to Rabaul’s very gates. On October 4 the “Sun Setters” of the 339th Fighter Squadron swept in on Kahili with their P-38s ahead of a B-24 attack. Commander Shibata Takeo’s 204th Air Group pulled out of Buin on October 8. AIRSOLS continued its harassment and threw a punch there on the tenth, in tandem with a Thirteenth Air Force attack on Kahili. By October 15 the enemy was reeling under another major attack on Buin, then similar raids almost daily. Japanese plane counters were tabulating 150 to 250 aircraft per mission. Each time, runways at the JNAF bases became unusable for hours at a time. Both Kusakas agreed conditions had become intolerable. Kusaka Jinichi ordered Rear Admiral Sakamaki to withdraw his 26th Air Flotilla to Rabaul. The last fighter unit, Commander Nakano Chujiro’s 201st Air Group, retreated to the fortress after October 22. The forward detachment of Captain Sato Naohiro’s medium bomber group held on at Buka until November 1, then abandoned it just before the base was creamed by a U.S. cruiser bombardment. Japanese power had shrunk to the hard kernel of Rabaul.
However, the Buin complex remained formidable, with the fields of Buin itself, Kahili, Ballale, and a new one at Kara. The Imperial Navy had real resources. In addition to almost a dozen big pieces of coastal artillery and twenty-one smaller cannon, a powerful array of flak guns defended the complex. These included ten 4.7-inch antiaircraft guns, seven 3.2-inch guns, twenty-seven 70mm weapons, seventy 25mm AA machine guns, and another forty of the 13mm variety. There were also sixteen searchlights. Protected by strong defenses, the Japanese could still slip planes through to strike the Allies farther south. Therefore SOPAC did not let up. By October 18, Japanese air commanders had to rate Ballale as beyond repair. Two days later they concluded that Buin itself could serve no further purpose. A week later Admiral Samejima moved Eighth Fleet headquarters from Shortland back to Rabaul.
In the meantime something happened in the Central Pacific that affected the siege of Rabaul. Combined Fleet C-in-C Koga, sensitive to an American advance, stood ready to implement his decisive battle scheme. For his part, Admiral Nimitz had created a Central Pacific Force in early August, and put his newly invigorated carrier unit to work raiding Japanese-held islands. Marcus was hit late in August and Tarawa in September. Admiral Koga sortied from Truk in response to the latter attack. In early October the Americans—now with six flattops—struck Wake. Radio traffic analysis convinced Admiral Koga that Nimitz was about to raid the Marshalls. Koga led the Combined Fleet out of Truk on October 16. Measures of how seriously Koga took the threat lie in his orders for an I-boat to reconnoiter Pearl Harbor, in his air reinforcements to the Marshalls—for which planes were actually recalled from Rabaul—and in a surge of radio traffic on Imperial Navy command circuits, combined with a change in the JN-25 code, making it temporarily unreadable. But there was nothing for Koga to find. Disappointed, he returned to Truk on October 26. This is important, because the frustrated Koga, having twice chased phantom menaces, suddenly faced an actual threat in the Solomons.
Without a doubt the acceleration of operations, from the Japanese perspective, had become quite disturbing. Barely three weeks before, on October 6, the Imperial Navy had fought a sharp destroyer engagement in The Slot to protect its withdrawal from Vella Lavella. Then in short order Fortress Rabaul had been attacked massively, the Japanese air force had been driven out of Bougainville, and JNAF attacks in New Guinea had continued ineffective. When flagship Musashi dropped anchor off Dublon in Truk lagoon, Rabaul had just endured three straight days of Allied air raids. Shortly after dawn on October 27, a JNAF scout just south of New Britain saw the fleet carrying New Zealand troops to invade Stirling and Mono islands in the Treasuries.
Koga Mineichi had a contingency plan for something called the RO Operation. This involved rapid reinforcement of the Southeast Area Fleet to regain the initiative in the Solomons and New Guinea. Admiral Koga decided to put that into effect. He alerted Vice Admiral Ozawa of
the Kido Butai to prepare to send his carrier planes to Rabaul. Allied codebreakers recorded a high volume of priority traffic on the Truk-Rabaul circuit. The next day’s Ultra summary noted “what appeared to be a short directive possibly modifying, canceling, or putting into effect a prearranged plan or phase of operations, possibly as a result of recent Allied activity in the northern Solomons.” The message originated with the C-in-C of the Combined Fleet. It was addressed to commands charged with “frontier defenses.” The fat had gone into the fire.
INVASION
The Bougainville invasion was the Big Show. Everyone was there. Bull Halsey moved his SOPAC headquarters up to “Camp Crocodile” on Guadalcanal for the occasion. There he met with Rear Admiral Wilkinson, the amphibious force commander, and Lieutenant General Alexander A. Vandegrift, leading the I Marine Amphibious Corps. Even Vandegrift came back for Bougainville, though his participation resulted from tragic circumstances. The general leading the corps had fallen to his death from an open window at Nouméa. Vandegrift, headed to Washington to take charge of the entire Marine Corps, made a detour to help Halsey. But the selection of a new permanent commander had already been made—Major General Roy S. Geiger, once the Cactus air boss. The Bougainville landing was a gathering of the clan. On October 30 Vandegrift and Wilkinson embarked on transport George Clymer for the last leg of their voyage to the invasion area. The George Clymer too had been at Guadalcanal, where she had landed supplies and brought back Japanese prisoners.
Tip Merrill had his cruisers at the invasion; Arleigh Burke, his destroyers. Sailor Jim Fahey, fresh from liberty in Australia, manned his 40mm flak tub on the main deck of the Montpelier. As a result of Halsey’s recent visit to Pearl Harbor and appeal to Admiral Nimitz, the Pacific Fleet had left the light aircraft carrier Princeton in SOPAC, and she, along with the Saratoga, were providing the carrier support, under Rear Admiral Ted Sherman, another South Pacific stalwart. Ray Calhoun aboard his destroyer Sterett soon arrived in a carrier group screen. Nimitz was now so flush with flattops he promised Halsey the loan of another group, even though he was set to kick off his Central Pacific offensive. John F. Kennedy had his PT-59 working in the simultaneous Marine diversion on Choiseul. Ace pilots Pappy Boyington, with his “Black Sheep” squadron, and Jimmy Swett of VMF-221 were flying over the beach providing air cover. It seems the only ones not at the party were the Japs.
Admiral Halsey made an inspired choice of invasion site, Cape Torokina, at one end of Empress Augusta Bay. Bull Halsey was to secure airfields on Bougainville to aid in the suppression of Rabaul. Though Bougainville was replete with Japanese bases, those were the very places where the enemy concentrated. At the southern end, around Buin there were more than 12,000 Imperial Navy sailors and 15,000 Japanese Army soldiers with their coast artillery, strong flak, and the stockpiled supplies that had supported all the Solomons. The main strength was the 6th Infantry Division with 17th Army headquarters under General Hyakutake Haruyoshi—the Japanese veterans of Guadalcanal, hardened by their ordeal. At Kieta on the east coast were another 6,000 troops plus some naval personnel. At Buka in the north were 6,000 more men, most of them from the Army. Across the island as a whole there were some 40,000 Japanese Army troops and 20,000 Imperial Navy men—again outnumbering a native population of about 40,000—but in the Empress Augusta Bay sector there were only two to three thousand of the enemy, and in the actual invasion area just 270 Japanese with a single gun.
So the landing would be easy. Even though scout parties had recently discovered swampy land behind the beaches, due to the prowess of the Seabees, who had refined their airfield construction techniques into an engineering marvel, the airfield part would be relatively easy too. While this gets ahead of our story, the 71st Seabees completed the first of two Torokina airfields in just forty days with the war raging all around them. Ground crews arrived the day before the Seabees finished, and Marine Fighter Squadron 216 became the first occupants of what became key bases for the siege of Rabaul.
Getting from here to there was still the problem, but Halsey began with a smart choice of objective and funneled the entire 3rd Marine Division and 2nd Raider Regiment through a narrow beachhead on L-Day, November 1. In the amazingly short time of eight hours the invasion fleet landed 14,000 men and 6,200 tons of supplies. The worst aspect was dangerous reefs and currents that swamped a number of landing craft. The Marines fought their way inland. Japanese troops inflicted some casualties but fell back before this host. The Americans soon had a mile-deep beachhead they continued to expand. The real fight on Bougainville would not take place until weeks later, once Hyakutake had had time to march big units down from Buka and up from Buin. During that interval, in a series of transport echelons, General Geiger, who replaced Vandegrift shortly after L-Day, brought in additional troops and equipment. A great novelty would be the return of the coastwatchers, infiltrated from submarine Guardfish, the first time these spies inserted behind enemy lines as part of an invasion.
Japanese commanders knew the threat posed by Allied forces on Bougainville. They reacted instantaneously. Nothing was possible from Buka—Tip Merrill with his cruiser group administered a drubbing to that base area the night before the landing. During the predawn hours Merrill raced south to do the same at Shortland. Sherman’s carrier planes busted up Buka too, and AIRSOLS helped suppress the Buin complex with a nightmarish succession of air strikes—more than a dozen, totaling 344 planes.
That left Rabaul. On the basis of an air scout’s report the previous day, Admiral Kusaka had already sent a surface action group to intercept the invasion fleet. Rear Admiral Omori Sentaro with his Cruiser Division 5 had just escorted a convoy to the fortress, so his heavy ships formed the fleet’s backbone. Omori believed the Allies bound for the Shortlands. A succession of confusing reports pulled him in different directions and finally he returned to Rabaul, arriving on L-Day morn. Admiral Samejima thought it better to hustle Omori back to Truk, but Kusaka overruled him. Omori’s chance to meet the Americans in a battle royal at just the point when they were nearing Cape Torokina was lost. But Southeast Area Fleet now learned the invasion had begun. Kusaka ordered troops assembled for a counterlanding, and Samejima instructed the Omori fleet to escort them. The cruiser commander received his orders in the early afternoon.
Rabaul’s airfields were busy that day. Admiral Ozawa’s Carrier Division 1 planes were streaming in. Ozawa departed Truk and flew off his air groups 200 miles north of the fortress. Vice Admiral Ozawa brought Kido Butai headquarters to Rabaul, establishing his command post on land on November 1. Receiving this substantial reinforcement of 173 warplanes, Kusaka might yet smash the Bougainville landing. Air strikes could soften up the enemy; Omori would hit them with a compact but powerful force. Allied intelligence made up the fly in this ointment. On October 30, traffic analysis indicated aerial reinforcements en route to the Southeast Area. Then came Halloween. Ultra revealed Kusaka informing Koga that his disposable force numbered only seventy-one fighters and ten dive-bombers. A series of messages discussed urgent reinforcements. The Allies detected movement of a number of fighter and bomber squadrons alongside “possible” deployment of Kido Butai carrier planes. Kusaka’s increased air strength would be no surprise. Another decrypt disclosed the arrival of Admiral Omori’s cruiser unit. On November 1, Ultra reported the Japanese expecting a surprise U.S. landing, perhaps even on the coast of New Britain. Bougainville happened instead.
The Japanese response could just possibly have worked. A one-two punch might drive Halsey’s fleet away. Bougainville could then be sealed tight by Kusaka’s pumped-up air force. Roy Geiger’s Marines would become beleaguered the same way the Americans had been on Cactus in that now dimly remembered past. General Hyakutake could assemble his ground troops and obtain revenge. The Japanese were in an excellent position to do this. But since August 1942, their power had deteriorated markedly. The consequences became apparent in the air strikes against Empress Augusta Bay. The first came early in the morning. The J
NAF mustered only seven dive-bombers with forty-four Zero fighters. Then came a pure fighter sweep by eighteen Zeroes. Early in the afternoon there was a mission flown by seven Vals accompanied by forty-two fighters. Though JNAF fliers claimed sinking cruisers and transports and setting many landing craft afire, the Allies seem to have suffered no damage whatsoever. Against that nugatory result, the Japanese lost seventeen fighters and six bombers, with ten more planes damaged, two of them seriously.
That night Kusaka sent seven torpedo-armed Bettys accompanied by scouts and flare planes against Sherman’s carriers off Buka. Admiral Sherman recounts that his crews had reached the point of complaining they never saw any action, grousing that land-based air got the juicy assignments. The Buka strikes supplied a corrective, while the pyrotechnics of a Japanese torpedo attack at night woke them right up. Several attack aircraft were splashed.