The Bougainville Invasion (Part 3): December 1943 – March 1944

We resume the quite comprehensive articles provided by CINCLAX as part of the ongoing Solomon Islands Campaign blog project.  With the exception of some noteworthy battles at sea and on land, the Solomons campaign slogged on in near anonymity, except for those doing the fighting.  We would learn much in the process – about joint operations, supporting forces ashore, the flexibility of carrier- and shore-based air, logistics and the like that would be applied in the coming campaigns through the Southwest and Central Pacific that would break the back of the Japanese military and lead the way to ending the war in the Pacific.  That, however, lays still in the future.  In the meantime, Bougainville continues…

– SJS

Expansion of the Torokina Beachhead

The first—or 3rd Marines—part of the Bougainville campaign had cost the Marines 423 killed and 1,418 wounded. Japanese dead were counted at 2,458; only 23 were taken prisoner. It had been a remarkably smooth operation.

On December 15, 1943 command of the Torokina beachhead Area had passed from IMAC (MG Roy Geiger) to XIV Corps (MG Oscar Griswold). Almost all of the 3rd Marines were withdrawn by the end of the month, and the Americal Division (MG John R. Hodge) and 37th Division (MG Robert Beightler) moved in to take their places. In fact elements of the 37th had already been in place, and initially Geiger had assigned them to the comparatively “peaceful” western part of the perimeter. Of the Marines, only the 3rd Defense Battalion would remain. Their 155mm guns would prove invaluable in defense of the perimeter.

Meanwhile the airfields were being readied to reduce Rabaul and its environs. Since December 10th, F4U Corsairs of VMF 216 had been based on the new Torokina strip, and they would initially be the key to the successful AirSols bombing offensive against Rabaul. Before the Piva strips became operational on January 9th, Allied bombers would lift off from more distant fields and be joined by the Torokina fighters, so as bomber escorts they made feasible large-scale raids from elsewhere.

During the initial period of the landings, air activity in support of the beachhead, consisted of daily flights over the Torokina area, in close air support (CAS), as well as regular strikes on southern Japanese bases like Kahili, Kieta, Kara and Ballale, and as visits to Buka and Bonis in the north.

Meanwhile the Marines were perfecting their CAS techniques, and on ten occasions in November-December ground troops requested it. Each of these required that the strike be run within 500 yards or less from American front lines; three at 500 yards, three at 200 yards, one at 120 yards, one at 100 yards, and two at only 75 yards. Marine spotter aircraft used colored smoke to mark front line positions and white smoke to mark the target areas, setting up a solid liaison between air and ground units. Techniques developed here would form the doctrinal basis for later Marine campaigns.

Very occasionally Japanese aircraft from Rabaul would score hits on command posts, supply dumps, ships, or small craft in Puruata Harbor (between Puruata Island and Cape Torokina), and on airfields which were under construction within the American perimeter. The net effect of these raids was minimal, and as enemy air strength diminished on Rabaul, raids dwindled to virtually nothing by the end of February 1944.

In time, most of AirSols assets would move to Bougainville, and it would become AirNorSols in June 1944.

The Americal Division was somewhat unusual in that it had never been given a number designation. In fact it was so-named because it had been formed up in May, 1942 in New Caledonia (representing the “Cal” part of the name). The Americal was also the first Army Division to take offensive action against the Japanese, and had fought with some with some distinction in the latter phases of the Guadalcanal campaign.

Like many other early Army divisions, the Americal was formed from National Guard Regiments, in this case 132nd (Massachusetts), the 164th (North Dakota), and 182nd (Illinois).

The 37th, or “Buckeye Division,” also had National Guard roots—only from Ohio. It had originally been formed in Fiji, then moved to Guadalcanal for training in March 1943. Four battalions had assisted the initially hapless 43rd Division on New Georgia, and learned their trade the hard way in the attack on Munda. It was at Munda that XIV commander Griswold had “cut his teeth” as he straightened out the faltering Army effort.

ARMY GROUND COMMANDERS – MG Robert Beightler (left) was the only CO the 37th Division would ever have in WW II. MD John Hodge was the Americal Division CO on Bougainville.	The 37th Division was assigned the western sector of the beachhead, formerly occupied by the 3d Marine Division, the 37th extended its right flank and took over some 2,000 additional yards of perimeter.	THE PIVA AIRFIELDS – (shown here in February 1944 photograph) became key bomber and fighter strips in the aerial offensive against Rabaul. Piva Yoke is the nearest strip; Piva Uncle lies behind it. In the distance, near the sea, is the original Torokina fighter strip, opened in December 1943.

Hyakutake’s Last Counterattack, March 9-17

After his December failure to dislodge the Marines on and around Hellsapoppin’ Ridge, and now cut off from any significant supplies or reinforcements, one might assume that GEN Hyakutake would return to Buin and await a war outcome effected by people other than himself. But the old Guadalcanal veteran had lots of fight left in him.

In January and February 1944, the general’s men built or improved trails, so that the 17th Army could move from southern Bougainville to assembly areas in the hills inland from the XIV Corps’ perimeter. By mid-February the soldiers were on their way. Hyakutake planned to use the main strength of his 17th Army, which consisted principally of the 6th Division and several battalions of the 17th Division that Imamura had sent down from Rabaul in early November. The 6th Division was allegedly the toughest in the entire Japanese Army, and its commander, GEN Kanda Masatane, was a noted firebrand. Just before they attacked in March, he spoke to his men:

We must fight to the end to avenge the shame of our country’s humiliation on GUADALCANAL . . . . There can be no rest until our bastard foes are battered, and bowed in shame–till their . . . blood adds lustre . . . to the badge of the Sixth Division. Our battle cry will be heard afar. . .

Griswold first knew something was afoot, as a reconnaissance in force of Fijian troops, under New Zealand command, went up the Numa Numa trail to see what they could find. A mile or so north of the XIV Corps perimeter, they were met by a strong Japanese force and had to quickly retreat.

Making the same mistakes twice

Total Japanese strength involved was about 15,000, while Hyakutake had underestimated his foe by nearly an entire combat division. In an interesting way, Japanese strategy was a repeat of their October 1942 offensive on Guadalcanal, and authored by the same man. Essentially it meant slogging through the jungle to circumnavigate the American perimeter and flank it at several points, while hopefully remaining undetected traveling over long jungle trails. Just as on the ‘Canal, the Americans on Bougainville enjoyed interior lines of communication, via a well-developed network of roads to sprint reinforcements to any threatened section of the perimeter. Meanwhile the flanking Japanese units had to make do with what they could carry through the jungle; if they needed additional troops, ammunition, food, medical supplies, etc., they were basically out of luck.

But unlike Guadalcanal, this time there would be no friendly IJN battleships and heavy cruisers arriving to support the Japanese attack; now all off-shore gunfire would be from American sources. There would be no more daily air raids from Rabaul or Kahili or the Shortlands, either. Now AirSols enjoyed overwhelming strength and air superiority, and was ready to respond with large-scale close air support.

In October 1942 Hyakutake’s attack failed miserably and was repulsed with heavy losses. His Bougainville efforts would reap similar results.

Preliminaries

As they had tried before at Koromokina Lagoon in November, the Japanese had still hoped to launch an amphibious counter landing, coupled with an attack on the American perimeter inland. A shortage of Daihatsu landing barges made this very difficult, although it was not for lack of trying against increasingly strong LCI(G) and PT patrols. Nevertheless the Japanese had some success, and barges operating on moonless nights did manage to transport some heavy equipment, including artillery, to a point east of Cape Torokina from where it was laboriously hauled inland into the hills around the perimeter.

Meanwhile, at the beginning of March 1944 XIV Corps’ perimeter was somewhat larger than it had been when Griswold took over from the 3rd Marines in December. The beach frontage had been pushed eastward a bit and now totaled about 11,000 yards, while maximum perimeter depth was about 8,000 yards, or just northeast of Hellsapoppin’ Ridge.

Griswold’s main combat force was roughly split between Hodge’s Americal and Beightler’s 37th Divisions, totaling some 27,000 men, all veteran jungle fighters (Americal on Guadalcanal, 37th on New Georgia). All of Griswold’s combat regiments were placed on the perimeter and had had weeks to improve their defensive positions. Another 35,000 personnel, including AirSols, Marines and Navy, were attached to the XIV Corps. All these men had had at least a modicum of weapons training, and as events would show, had no fear of jumping into a battle. Indeed Griswold had previously taken measures to prevent “rear echelon” people from taking a rifle to the front lines “to get me a Jap.”

Hayakutake’s attack, dubbed the “TA” Operation, planned for three attack forces, largely acting independently. Named after their commanding generals, these were:

• The Iwasa Unit – 2nd battalion of the 13th Infantry Regiment, the 23rd Infantry Regiment, plus two batteries of field artillery and supporting troops. These troops assembled behind Hill 1111 (see map above).
• The Magata Unit – the 45th Infantry Regiment, plus some mortars and field artillery. They assembled at Mt. Nampei, on the Numa Numa Trail, the only cross-island path on Bougainville.
• The Muda Unit – the rest of the 13th Infantry Regiment, plus engineers. This contingent assembled at Peko, a village on the East-West Trail
• An artillery group commanded by COL Saito consisted of four 150mm howitzers, two 105mm howitzers and various smaller pieces. About 300 rounds per gun were allotted.

Hayakutake’s plan was to make two thrusts from the north on March 8th, then reorganize on the 9th and 10th and move on the Piva airstrips. Simultaneously the Muda Unit was to seize two hills then join with a battalion of the Iwasa Unit to attack Hill 608 from the southeast and northwest. After that, assuming everything went to schedule, on March 11th the Magata Unit was supposed to unite with the Iwasa Unit and capture the Piva strips. Then all Units were to drive to the sea and capture the Torokina fighter strip by March 17th. In typical Japanese fashion, it was an incredibly complex plan with little allowance for any local setbacks or flexibility to cope with American responses that might differ from expectations.

In short order, the Japanese attack was soundly defeated. Their artillery was quickly silenced by AirSols dive bombers and naval gunfire; then GEN Beightler sent in M-4 tanks (Shermans) when the enemy got inside the perimeter near the Piva strips. Helping out were Seabees and even medical personnel, who serviced aircraft under fire and occasionally rushed into the front line. On March 24th-25th Kanda’s 6th Division made its last attempt, at one point succeeding in getting within 25 yards of a battalion command post. But all for naught; on the 27th the Japanese were expelled from Hill 260, nearly one half mile outside the perimeter.

And so the battle was over. The largest Japanese land attack in a year and a half was routed. Hayakutake lost 5469 KIA, Griswold 263.

Still, it hadn’t been easy. Corps Commander Griswold, after eight major enemy attacks, wrote in a letter four days later:

I am absolutely convinced that nowhere on earth does there exist a more determined will and offensive spirit in the attack than that the Japs exhibited here. They come in hard, walking on their own dead, usually on a front not to exceed 100 yards. They try to effect a break-through which they exploit like water running from a hose. When stopped, they dig in like termites and fight to the death. They crawl up even the most insignificant fold in the ground like ants. And they use all their weapons with spirit and boldness . . . . Difficult terrain or physical difficulties have no meaning for them.

The Japanese would make an additional series of half-hearted attempts, mostly by barge convoys from Buin. Again, CAPT “Scrappy” Kessing’s “Bougainville Navy” of LCI(G)s, PTs and destroyers shot up every small group of Japanese soldiers who got close to the shores of Empress Augusta Bay. Now for Hayatuke, the war was finally over. Marooned in southern Bougainville, out of food and supplies and with discipline rapidly declining, he was forced to assign most of his troops to growing vegetables in order to survive. In 1945 he suffered a stroke and was replaced by Kanda as CO of the 17th Army.

Final Analysis

In retrospect Hyakutake’s plan was as unsound as his 1942 Guadalcanal attack. He spread out his forces and attacked in three places, whereas he would certainly have inflicted more damage on XIV Corps had he concentrated his forces and broken through the perimeter into the rear areas. With little artillery and absolutely no air support, the Japanese could not afford to delay any aspect of their attack, while American gunfire and CAS methodically eliminated pockets of Japanese resistance when their attacks stalled and they were forced onto the defensive.

References

• The Pacific War Online Encyclopedia (http://pwencycl.kgbudge.com/) © 2006-2009 by Kent G. Budge
• Bougainville, 1943-1945: the Forgotten Campaign, Harry Gailey, University of Kentucky Press, 1949
• General Kenney Reports, George C. Kenney USAAF, Duell, Sloan & Pearce, Inc., 1949
• Cartwheel: The Reduction of Rabaul, John Miller, Jr., U.S. Army in World War II – The War in the Pacific, Office of the Chief of Military History, Department of the Army, Washington, DC, 1959
• Breaking the Bismarcks Barrier, Vol. VI of History of U.S. Naval Operations in World War II, by Samuel Eliot Morison, Little, Brown, 1950
• Bougainville and the Northern Solomons, MAJ John N. Rentz, USMCR, Historical Branch, Headquarters, U.S. Marine Corps, 1946
• The Siege of Rabaul, Henry Sakaida, Phalanx, 1996
• Japan’s Fatally Flawed Air Forces in World War II, John W. Whitman, Aviation History, issue of September 2006