IV: The Japanese Move Back
IV: The Japanese Move Back
The growing strength of American naval, ground, and air forces and the withering losses of the campaign, ultimately forced the Japanese High Command to order the evacuation of the island and establish a line which included New Georgia, Kolombangara, Vella Lavella and intervening islands, with Munda as a central pivot. Imperial General Headquarters made the decision on 31 December and issued orders for the evacuation on 4 January 1943 to Hyakutake, who remained on Guadalcanal until early February. Destroyers were employed for the evacuation, with 80 large barges, 100 small barges, and 300 collapsible boats to uplift men and materials from the shore. The first units of 38 Division left the island on the night of 1 February from beaches round Cape Esperance—site of the Japanese base, 25 miles along the coast from Henderson Field; the evacuation was completed by 8 February, by which time 12,000 army and about 1000 naval personnel were moved to concentration areas in Southern Bougainville and the Shortland Islands. According to Japanese records, 3500 of these went into hospital suffering from beri-beri, dysentery, and malaria; 600 of them died.page 222
American intelligence failed to appreciate the Japanese evacuation which, because of the concentration of shipping in anchorages to the north, was mistaken for another attempt to land reinforcements on a large scale. A report made on 17 April 1943 by the American Commander-in-Chief of the Pacific Fleet confessed that ‘Not until after all (Japanese) organised forces had been evacuated on 8 February did we realise the purpose of their air and naval dispositions; otherwise, with the strong forces available to us ashore on Guadalcanal and our powerful fleet in the South Pacific, we might have converted the withdrawal into a disastrous rout’. The cautiousness of commanding officers in action for the first time may have been partly responsible for a certain lack of aggressiveness among the men fighting the jungle as well as the Japanese.
Guadalcanal cost the Japanese at least 24,000 officers and men killed in action and lost in sunken ships. Figures gathered from both American and Japanese sources, which are as accurate as any figures of this campaign can be, since most of the enemy records were either lost or destroyed, state that between 36,000 and 37,000 Japanese fought on Guadalcanal between August and the end of December 1942; 14,800 were killed or missing and 9000 died of disease. Of these, 4346 were drowned at sea; 1000 were taken prisoner. Only 2516 of 7648 officers and men from 38 Division who landed on the island returned to bivouac areas in the Shortland Islands. Six hundred aircraft and their pilots were also lost in attempting to hold the island.
The Japanese at first did not appreciate the necessity for a series of intermediate air bases through the Solomons, beginning them hastily only when losses on the 600-mile journey between Rabaul and Guadalcanal weakened their air power. Weather conditions changed so swiftly during this flight that operations were hampered and required drastic changes from the original plans. A seaplane base was therefore established at Rekata, on Santa Isabel; an airfield at Buin, in Southern Bougainville, was ready by 7 October; Munda, in New Georgia, by the end of December; and Vila, on Kolombangara, also in December. By that time, of course, the fate of Guadalcanal was sealed. Ten destroyers used in running the Tokyo Express were sunk and 19 damaged. By comparison American army losses in manpower were light—1752 killed and missing out of a total of 6111 casualties. Navy losses were much more severe. Throughout the whole campaign the Japanese made excessive claims of sinking and damaging American naval craft and of destroying aircraft.page 223
Following the retreat from Guadalcanal to the Central Solomons line, 17 Japanese Army was given the task of defending Bougainville in support of a new line swinging on Munda, where, in February, Rear-Admiral Ota established his headquarters and took command of 5500 navy and army personnel. Ota, who was commander of 8 Fleet Special Unit, was made responsible for all Central Solomons operations, but he had great difficulty in controlling navy and army units, since Army refused to send in any more men. Differences of opinion between army and navy commanders after the withdrawal to New Georgia weakened the Japanese defence plans, and the continual cancellation and reissue of orders by 8 Area Army, which was formed at Rabaul to direct the whole of the Solomons and New Guinea campaigns, produced confusion which destroyed any unity of command.
In March, also, Japanese morale suffered a blow by the loss of Admiral Isoroku Yamamoto, Commander-in-Chief of their Combined Fleet, who was the dominating mind in Japanese naval strategy and originator of the attack on Pearl Harbour. On 18 March he left Rabaul by special aircraft, accompanied by his chief of staff and several senior staff officers and escorted by nine fighters. While on their way to Buin, in the south of Bougainville, where Yamamoto was to inspect both army and navy units and inspire them to further effort, the flight was intercepted by American fighters and the two planes carrying the Commander-in-Chief and his senior staff officers were shot down. Yamamoto was killed when his machine crashed into the jungle; the other machine fell into the sea, injuring all the occupants. Vice-Admiral Kondo took over command of the Combined Fleet until the arrival of Admiral Mineichi Koga, commander of the China Fleet. Through the following months Ota's garrison was increased until, by the end of June, there were 10,500 men in the New Georgia and Kolombangara areas deployed to protect airfields and fleet anchorages, and another 3400 round Rekata seaplane base on Santa Isabel. Early that month he was relieved by Rear-Admiral Noboru Sasaki, whose instructions were to unify and command naval and army forces in all land operations.
Meanwhile American strength was increasing in readiness for an advance into the New Georgia area, with Munda as the next objective. Throughout June, action on sea and in the air paved the way for the landing at Rendova on 30 June. On that and the following day 125 Japanese aircraft were shot down, heartening proof of Allied air superiority. Although the Japanese put up a stout resistance and prolonged the battle for New Georgia for six weeks against 14 Corps, which was forced to commit its three page 224 divisions, the commander of the garrison reported ‘we were overwhelmed by the enemy's material and military strength’. By this time the Americans had reduced disembarkation to a speed which baffled the Japanese, and from then on until the end of the campaign the Japanese were outmanœuvred. ‘Our losses in men and planes were beyond our estimation’, the Southern Army commander, Terauchi, reported to Tokyo in June.
The Japanese were never able to anticipate the next Allied thrust in the Solomons. After the fall of Guadalcanal, they did not expect the attack to continue to the next objective for at least a year. Although land action in the jungle was slow and laborious, the pressure of naval action at sea was maintained without ceasing. Through the months of preparation by the land forces, strong naval units bombarded at night the Munda and Vila airfields and Japanese installations throughout the area, and shot up barge traffic known to be running between the islands.
The Japanese lost as heavily in attempting to hold and reinforce their garrisons in the New Georgia Group as they did in finally evacuating troops from islands to which they had been driven as Griswold's corps closed round Munda, which fell on 5 August. Fighting, however, continued for another fortnight on adjoining islands of the group. Small groups of reinforcements had reached New Georgia in barges, torpedo boats, and submarine chasers, running in under cover of darkness, and when Munda fell efforts were made to strengthen Kolombangara so that any remaining island garrisons could be maintained from that base.
The final attempt to reinforce Kolombangara on the night of 6–7 August, anniversary of the opening battle for Guadalcanal, ended in complete disaster. Units of 6 and 38 Divisions were despatched from Southern Bougainville under the protection of four destroyers. As they passed into Vella Gulf they were intercepted and taken completely by surprise by an American task force, commanded by Commander Frederick Moosbrugger, which had been ordered to sweep the gulf to disrupt such traffic. In a few minutes three of the enemy destroyers were sunk and the fourth heavily damaged. Most of the reinforcements were drowned—820 army and 700 navy personnel; 190 army and 120 navy survivors reached the shores of Vella Lavella on rafts or by swimming and joined the garrison which had been sent there previously to organise staging bases and lookouts.
That same night Admiral Sasaki, the Munda commander, moved his headquarters back to Vanga Island, and the following night to Kolombangara. On 14 August he was instructed to withdraw page 225 all the Munda garrison, and the following day American forces landed on Vella Lavella. This was the beginning of the by-passing strategy which was continued during the remainder of the Solomons campaign. Remnants of the Japanese forces from New Georgia had concentrated on Arundel and Gizo Islands by 16 August, but as Griswold's forces closed round them they moved piecemeal to Kolombangara by barge, the last units leaving Gizo on the night of 21 September, the day on which 14 Brigade of 3 New Zealand Division began operations to clear Vella Lavella of the enemy.
The loss of Munda and Vella Lavella seriously menaced the Japanese forces on Kolombangara, who were now outflanked, with all their supply routes severed, and Sasaki was instructed to continue his withdrawal to Bougainville, moving via staging bases on Choiseul. On the night of 28–29 September, while 3 New Zealand Division units were forcing the Vella Lavella garrison into the north of the island, 2115 Japanese sick and wounded were uplifted from Kolombangara in three destroyers and taken direct to Rabaul. Small parties continued the evacuation, making their escape at night in barges and torpedo boats, and on the nights of 1–2–3 October the last of the garrison departed—5400 moving in 136 barges and other small craft and 4000 in six destroyers. Twenty-nine barges and torpedo boats were destroyed by American destroyers and motor torpedo boats, but the Japanese records, from which the above figures were taken, state that 12,435 all ranks from Kolombangara and Choiseul reached Buin and Erventa in Bougainville. On the night of 6–7 October the last of the Vella Lavella garrison was uplifted under cover of a naval engagement, which is recorded here merely to emphasise the Japanese propensity for making excessive claims of damage. During this action, fought in the midnight hours north of Vella Lavella in violent rain storms, they claimed to have sunk two American cruisers and three destroyers, whereas only three American destroyers opposed them. (See Chapter 5.)
The loss of New Georgia and Vella Lavella created further strife among Navy and Army leaders concerning future defence strategy and caused the Japanese High Command to modify their Z plan, which was conceived by Yamamoto, and withdraw their vital defence line to the Kurile-Mariana-Caroline Groups. This Z plan originally established an unyielding line for the defence of the Japanese mainland running from the Aleutians through Wake Island, the Marshalls, the Gilberts, Nauru and Ocean Islands, and the Northern Solomons to the Bismarck Group, with the Combined Fleet retained as a mobile reserve to attack any invading force at any place in or on that line. Further modifications became necessary page 226 as this line was broken by successive actions through 1943 and 1944. After the fall of Vella Lavella the Japanese were given no respite. As soon as an airfield was ready at Barakoma, a further thrust was made into the Treasury Group by units of 3 Division supported by American formations. This and a diversionary raid on Choiseul paved the way for a large-scale landing at Empress Augusta Bay on Bougainville on 1 November 1943.
Unable to anticipate the next Allied thrust, the Japanese concentrated their main force in areas in Southern Bougainville, with 17 Army Headquarters established near Buin, but despite their numerical strength, in the descriptive language of the soldier, they were never able ‘to take a trick’ during the remainder of the campaign. Ground strength numbered 15,000 troops, mostly from 6 Division, and there were also 6800 base personnel who were employed for the defence of loading installations and the two airfields outside Buin, where Mikawa, commander of 8 Japanese Fleet, also had his headquarters. The airfield on Ballale Island, in Shortland Bay, was also defended by naval units. About 5000 men of 4 South Sea Garrison Unit and a formidable force of coastal and anti-aircraft artillery units were deployed on Shortland Island, only about eighteen miles across the water from Mono Island, where 8 Brigade of 3 New Zealand Division was securely established. There were between 2000 and 3000 troops and naval lookouts in the Gazelle area and another 4000 to 6000 army and 200 navy personnel stationed in the Kieta area, midway along the north-east coast of Bougainville. All these were by-passed when Griswold's 14 Corps landed at Empress Augusta Bay on 1 November, against little opposition but in territory which almost bogged down the landing forces.
Later, in March, when the Japanese moved a strong force through the mountains and launched a determined attack on the perimeter, they were driven off with severe loss. With the occupation of the Green Islands Group by 3 New Zealand Division in February 1944, enemy forces on Bougainville were completely isolated, so that they were forced to maintain themselves by growing their own food or by using native foods. Rice cultivated in large areas was one of the objectives of Allied aircraft operating from the Empress Augusta Bay airfields and they sought daily to destroy it with oil spray and incendiary bombs. The capture of Green Islands on 15 February and of Emirau Island on 20 March 1944 ended the Solomons campaign. New Zealand ground forces were then withdrawn from the forward areas, but air force units remained under American and later Australian command until the surrender of Japan on 15 August 1945.page 227
This translated extract from an 8 Area Army order, issued to the commander of 17 Army at the time 3 New Zealand Division occupied Green Islands, is a typical example of the fanaticism which prompted Japanese resistance, though it was not frequently exercised:
If supply should be stopped and there is no alternative but to starve, the troops will charge into the enemy before they are entirely exhausted and, obtaining food from the enemy sources, they will continue fighting up to the very last.
Five days after 3 Division landed on Green Islands, 8 Area Army reported that not one single moveable aeroplane remained to the Japanese command in the South Pacific area; 70 per cent of the remaining ground forces were living in unhealthy conditions in caves to which they were driven by the fury and accuracy of Allied bombing, and 8 Fleet had lost all its ships except a few landing barges. Japanese records compiled by former service staff officers from information available to them and from their own personal documents, gave the following losses of 8 Area Army:
From December 1942 to July 1944: killed in action and died of injuries, 52,684, including 12,679 drowned in sunken ships; died of sickness, 8216; seriously injured, 43,234. At the time of the surrender deaths in action were estimated at 55,379 and deaths from sickness 15,936.
From October 1943 few medical supplies reached elements of the army stationed beyond Rabaul, and when the war ended 17.3 per cent of the total strength was ill, 11.5 per cent of them suffering from malaria.