The final offensive on Guadalcanal

On 23 January 1943 American infantry entered Kokumbona, a coastal village west of the Matanikau River which had housed the headquarters of the Japanese Seventeenth Army since the autumn. Before dawn on the same day the last defenders of the Gifu, a fortified area on Mount Austen that had held up the Americans for five weeks, were killed. War chronologies record under this date that the Japanese “continue fighting in the western part of Guadalcanal”. That is true but incomplete: for several days they had been fighting solely to cover their withdrawal. The decision to abandon the island had been taken in Tokyo back in December, and the January offensive of Major General Alexander Patch’s XIV Corps – the largest American land operation on the island – struck an enemy that was preparing a secret evacuation.

Two further events of January 1943 are linked to this offensive: the attack by the submarine USS Silversides on a Japanese convoy on 20 January, and a mention of XIV Corps that chronologies place under 25 January.

The decision to withdraw

By the end of 1942 the Japanese troops on Guadalcanal were starving. Supplies brought in at night by destroyers – the so-called Tokyo Express – and drums of food dropped into the sea were not enough, and after the Battle of Tassafaronga deliveries shrank further still. According to American studies based on Japanese documents, by the first week of January only about 14,000 remained of the roughly 36,000 soldiers landed on the island since August, many of them too sick and exhausted to fight. Malaria, dysentery and malnutrition were killing more men than American fire.

During the fighting for Mount Austen, on 31 December 1942, Emperor Hirohito approved the request of the army and navy to evacuate the island. The plan was named Operation Ke. The troops were to fall back to the western tip of the island, around Cape Esperance, from where destroyers would take off the survivors over several nights at the turn of January and February. The new defensive line in the Solomons was to run through New Georgia, and the weight of the fighting was shifting to New Guinea. The order was brought to Guadalcanal on 14 January by the Yano Battalion, the last Japanese unit sent to the island, to act as a rearguard for the withdrawal, accompanied by Lieutenant Colonel Kumao Imoto of the staff of Lieutenant General Hitoshi Imamura’s Eighth Area Army. Late in the evening of 15 January Imoto delivered it at Kokumbona to Lieutenant General Harukichi Hyakutake. The Seventeenth Army staff, which had hoped to the last for a new offensive, accepted it reluctantly and on 18 January sent the plan out to the units; the 38th Division was to begin withdrawing on 20 January.

For a long time the soldiers in the front line knew nothing of these plans. The defenders of the Gifu and the hills above the Matanikau had been ordered to hold their positions – and they did so, although they had had no food since New Year.

XIV Corps

On the American side the change ran the other way: fresh forces were arriving. In December 1942 General Patch had relieved the exhausted 1st Marine Division, and his Americal Division had taken over the defence of the perimeter around Henderson Field. On 2 January 1943, when the last units of Major General J. Lawton Collins’s 25th Infantry Division and the rest of the 2nd Marine Division had reached the island, all American units on Guadalcanal and Tulagi were combined into XIV Corps under Patch’s command. Brigadier General Edmund Sebree took over the Americal Division. The corps numbered just over 50,000 men – a superiority several times over the starving Seventeenth Army.

Some lists state under 25 January that XIV Corps “arrived in the Pacific theatre”. That cannot be right: the corps did not sail in from elsewhere but had been formed on Guadalcanal itself more than three weeks earlier, and had been on the offensive since 10 January. The date of 25 January does, however, correspond to a regrouping during the pursuit: in the last days of January Patch formed the improvised Composite Army-Marine Division (CAM) from the 6th Marine Regiment and infantry regiments of the Americal Division, which from 26 January advanced westwards along the coast. It is also possible that the news of the corps’ creation was mistakenly transferred to this day.

On 5 January Patch issued the order to clear the island. The 2nd Marine Division was to advance from the Matanikau along the coast, the 25th Division was to complete the capture of Mount Austen and seize the hills in the forks of the Matanikau, and the Americal Division and the 147th Infantry Regiment were to guard the airfield. Patch, convinced by intelligence that the Japanese were preparing a new offensive, did not want to strip the perimeter.

Galloping Horse and Sea Horse

The offensive opened at dawn on 10 January, after a bombardment by six artillery battalions and air strikes. The 25th Division’s objectives were two hill masses named after their shapes on the aerial map: Galloping Horse – a sprawling ridge between the forks of the Matanikau – and Sea Horse, made up of Hills 43 and 44. The 27th Infantry Regiment attacked Galloping Horse from the north. It was held by Major Haruki Nishiyama’s battalion of about 600 men, which stopped the advance for three days with machine-gun and mortar fire, while heat and lack of water put more Americans out of action than Japanese bullets did. The defence was broken only by a daring attack by five men under Captain Charles Davis on a knoll that formed the pivot of the Japanese positions; by 13 January Hill 53, the horse’s “head”, was in American hands. The Americans counted about 170 bodies there and over the following days killed or scattered the rest of the battalion – according to American studies the Japanese lost about 400 dead in the area, while more than 200 survivors with Nishiyama broke through to their own lines on 19 January.

Meanwhile two battalions of the 35th Infantry Regiment had outflanked Mount Austen in a long march through the jungle and on 10 January attacked Sea Horse from the south. The Americans had learned some of these trails in December thanks to Carlson’s Long Patrol, whose last stage had led precisely to the slopes of Mount Austen. By evening they had taken both hills and cut off the Gifu. Their supplies were carried by islanders hired as porters, and when these could not keep up, B-17 bombers dropped food and ammunition. Colonel Akinosuke Oka, commander of the 124th Infantry Regiment, slipped away westwards with part of his staff; the Americans counted 558 Japanese dead around Sea Horse.

The fall of the Gifu

The Gifu held out longest – a horseshoe of 45–50 interconnected pillboxes between the summit of Mount Austen and Hills 27 and 31, defended by 500–600 men under Major Takeyoshi Inagaki. The Americal Division’s 132nd Infantry Regiment, which had been assaulting it since December, had lost 115 killed and 272 wounded by early January, and on 9 January it was relieved by the 2nd Battalion of the 35th Regiment. Its attack on 15 January was completely repulsed. Inagaki rejected an order from Colonel Oka, passed over the last telephone line, to break out westwards – according to American studies because he would have had to leave the sick and wounded behind. The Americans broadcast appeals to surrender in Japanese through loudspeakers; almost no one came out. On 17 January forty-nine guns fired on the fortifications, and from 18 January the infantry pushed in from the weaker western side, taking one pillbox after another until torrential rain halted the fighting.

A tank decided the outcome. On 22 January the Americans brought a single Marine Corps M3 Stuart light tank up the mountain – of the three sent, only this one negotiated the muddy trail. Covered by a dozen or so riflemen, it drove right through the Gifu, destroying eight pillboxes and opening a breach about 180 metres wide in the defensive line. During the night of 22/23 January, at around 2.30 a.m., Inagaki led roughly a hundred of his last men still able to fight in a suicidal charge; almost all were killed. The Americans lost 64 killed in the fighting for the Gifu between 9 and 23 January, and 175 in the whole struggle for Mount Austen. Japanese losses were never established; many of the wounded and sick died of hunger in the pillboxes.

Kokumbona

The Marines were attacking at the same time. On 13 January the 2nd and 8th Marine Regiments moved west along the coast and over the adjoining hills, and the 6th Regiment soon relieved the exhausted 2nd. When on 16 January part of Lieutenant General Masao Maruyama’s Japanese 2nd Division tried to withdraw, in line with the new orders, the 6th Regiment wheeled towards the sea and trapped them in a pocket. By 17 January, according to American figures, the Marines had killed 643 Japanese there and taken two prisoners.

On 20 January the 25th Division attacked Hills 87, 88 and 89 inland, which dominated Kokumbona. To the surprise of the Americans, who knew nothing of the withdrawal, resistance was weak: the 38th Division was just leaving its positions. On 22 January Collins also took Hills 90 and 91 and threatened to cut off the whole Japanese 2nd Division. The Japanese hastily abandoned Kokumbona and the army headquarters; the Americans occupied it on 23 January. Some Japanese units were surrounded and destroyed, but most escaped westwards.

From then on rearguards delayed the pursuit on a narrow strip, 270–550 metres wide, between the sea and steep coral ridges, cut every few hundred metres by streams. Patch still feared a Japanese landing and sent forward the equivalent of only one regiment at a time, keeping the rest by the airfield. On 26 January the CAM Division, advancing along the shore, was stopped at the Marmura River by the Yano Battalion, which fell back slowly over the next three days and from 29 January held a line on the Bonegi River. By the end of the month most of the surviving soldiers of the Seventeenth Army had managed to assemble in the Cape Esperance area.

Silversides off Truk

The war for Guadalcanal was also fought far from the island, on the routes along which the Japanese brought men and supplies to Rabaul and the Solomons. On 20 January the American submarine USS Silversides under Lieutenant Commander Creed Burlingame, on her fourth war patrol out of Brisbane, tracked a convoy heading towards the Solomons – according to some lists about 286 nautical miles from Truk in the Carolines. Two days earlier she had sunk the tanker Tōei Maru of about 10,000 tons off Truk, her largest prize of the war. She shadowed the convoy all day, overtook it at dusk and lay in wait on its course, then fired torpedoes at the overlapping silhouettes of the ships. Contemporary reports, on which popular chronologies rely, spoke of the transport Meiu Maru sunk and Surabaya Maru damaged; the American history of the submarine and later lists credit her with sinking three ships: Surabaya Maru, Somedono Maru and Meiu Maru. Immediately after the attack it turned out that an armed torpedo had stuck in one of the bow tubes; the captain ordered full speed astern and fired it again – successfully. Because of a fuel leak Silversides returned to Pearl Harbor on 31 January.

Such successes were still rare at the time. American submarines – mainly modern Gato-class boats – had begun unrestricted commerce warfare on 7 December 1941, but for the first year and a half of the war their main weapon let them down. The Mark 14 torpedo ran deeper than set and passed under the hulls; the Mark 6 magnetic exploder detonated prematurely or not at all, and the contact exploder often failed on a hit at right angles. Captains who complained were long blamed for poor shooting. Only tests carried out on the initiative of Admiral Charles Lockwood, from February 1943 commander of the Pacific Fleet’s submarines, exposed all three defects; the last was remedied in the autumn of 1943. Later American submarines sank most of the Japanese merchant fleet and cut Japan off from the raw materials of the south.

Place in the war

The January offensive was the last act of the Guadalcanal campaign. American intelligence read the Japanese preparations to the end as the prelude to a new offensive – as late as 26 January it warned of an offensive codenamed “Ke” – and so neither Patch nor Admiral William Halsey, commanding in the South Pacific, threw all their forces into the pursuit or sealed off the sea around Cape Esperance. On the nights of 1, 4 and 7 February 1943 Japanese destroyers took off 10,652 army soldiers, according to Japanese figures, and the Americans realised what had happened only on 9 February, when their columns met at the western tip of the island and declared it clear of the enemy. Some historians fault both commanders for letting the enemy escape despite their superiority on land, in the air and at sea; others point out that the evacuation of emaciated, sick men no longer changed the outcome of the campaign.

The balance of six months of fighting was heavy for Japan: by various estimates some 20,000–25,000 Japanese soldiers were killed or died of hunger and disease on and around the island, and the navy and air arm lost dozens of ships and hundreds of aircraft together with their experienced crews. For the first time in this war Japan gave up territory it had captured, and Imperial General Headquarters went over to the defensive in the South Pacific, shifting its effort to New Guinea and the central Solomons. For the Americans Guadalcanal became a school of jungle warfare and of cooperation between ground, naval and air forces. XIV Corps, from April 1943 under General Oscar Griswold, led the fighting on New Georgia that summer, and Patch and Collins later held commands in Europe – the former the Seventh Army, the latter VII Corps. The campaign opened the way to the Solomon Islands campaign, whose objective was Rabaul, and in the wider plan to the American offensive across the Pacific.