The Japanese on Guadalcanal

In early July 1942 Guadalcanal, a large, mountainous, jungle-covered island in the southern part of the Solomon Islands, became the target of both sides in the Pacific war at once. The Japanese navy was preparing to build an airfield on the plain beside the Lunga River on the island’s north coast. On the other side of the ocean the American chiefs of staff had just, on 2 July, signed a directive for the first offensive against Japan, aimed at the very same area. For the next five weeks the two sides were racing against time, although only one of them knew it.

Some chronologies state under 3 July that Guadalcanal was by then “firmly in Japanese hands”. That is an exaggeration. The Japanese had held neighbouring Tulagi since May, but on Guadalcanal itself on 3 July they had only small detachments, which had spent several weeks clearing ground for the future airfield. The main convoy carrying the construction workers did not arrive until 6 July, and even then the Japanese presence was confined to a strip of coast around Lunga Point. Inland, a dozen or so kilometres from the Japanese camps, British and Australian coastwatchers were still at work, and most of the islanders favoured the Allies.

From Tulagi to the Lunga

The Japanese arrived in the Solomon Islands in the spring of 1942. In March and April they occupied the northern part of the archipelago, including Buka and the Shortland Islands, and on 3 May they took Tulagi without a fight, the seat of the British Resident Commissioner. On Tulagi and the neighbouring islets of Gavutu and Tanambogo they set up a seaplane base, from which flying boats patrolled the Coral Sea. Guadalcanal, across a narrow channel, had something that tiny Tulagi and almost the whole archipelago lacked: a flat, grassy plain on the north coast where an airfield for land-based aircraft could be built.

Japanese officers inspected the ground by the Lunga on 27 May. The plan gained importance after the defeat at Midway in early June. The loss of four large carriers meant that the Imperial Navy could no longer cover distant operations with ships alone and had to rely on land-based aircraft deployed along a chain of island bases. On 13 June the Naval General Staff approved the construction of an airfield on Guadalcanal. On 19 June the site was inspected by Vice Admiral Shigeyoshi Inoue, commander of the Fourth Fleet at Rabaul, and the next day Japanese troops began cutting and burning the grass on the future runway.

The Guadalcanal airfield was meant to serve several purposes. Bombers from the Lunga would be able to reach the New Hebrides and New Caledonia, the bases along the American supply route to Australia. Reconnaissance aircraft could watch the whole of the southern Solomons and the eastern approaches to New Guinea. In the original plans the airfield was also to support Operation FS, the seizure of New Caledonia, Fiji and Samoa. After Midway that operation was postponed, and on 11 July the Japanese high command abandoned it altogether. From then on Guadalcanal became above all a forward bastion of the Empire’s defensive perimeter, shielding Rabaul from the south-east.

The builders on the Lunga

On 6 July a convoy of a dozen or more ships (twelve, according to some sources) arrived off Lunga Point. It brought two naval construction units, the 11th and the 13th, which had originally been meant to build an airfield on a captured Midway. Together they numbered some 2,500 men, a large proportion of them Korean forced labourers, plus several hundred naval troops to guard them. The whole force was commanded by Captain Kanae Monzen. The Japanese unloaded road rollers, lorries, concrete mixers, a small locomotive with wagons, a power plant, workshops and large stocks of food, and after a few days of preparation, around 9 July, work on the runway began. In the middle of the month a smaller group of civilian builders joined them, and signallers set up radio stations on Guadalcanal and Tulagi.

The work went quickly, and according to the plan the airfield was to be ready in early August. American figures compiled after the island was taken indicate that at the time of the landing some 2,230 Japanese and Koreans were on the Lunga; other estimates go as high as 2,800 men. These were, however, mainly labourers rather than soldiers. The Japanese had not fortified the coast and did not expect anyone to dare attack so far from their own bases. The newly formed Eighth Fleet under Vice Admiral Gun’ichi Mikawa, which took over responsibility for the area at Rabaul on 14 July, did not expect a serious American offensive in the coming months.

Watchers in the mountains

The Japanese construction was no secret. On Guadalcanal, as on the other islands of the archipelago, coastwatchers were at work: colonial officials, planters and missionaries who had stayed behind with radio sets after the Europeans were evacuated and reported every Japanese ship and aircraft. The network was run from Australia by Lieutenant Commander Eric Feldt of Australian naval intelligence. The most important coastwatcher on Guadalcanal was Martin Clemens, a young British district officer and captain in the British Solomon Islands Protectorate Defence Force. When the Japanese began building up on the Lunga, Clemens withdrew into the mountains with his radio and a group of local policemen, from where he could watch the plain. His reports, together with those of other coastwatchers, went to Townsville and on to the Allied commands.

The news from the ground was supplemented by aerial photographs taken by reconnaissance aircraft and bombers, which had been flying regularly over Tulagi since May, and by intercepted Japanese signals. By early July the US Navy already knew that an airfield was being built on the Lunga. In the second half of July two officers of the 1st Marine Division’s staff, Lieutenant Colonel Merrill Twining and Major William McKean, flew over Guadalcanal and Tulagi aboard a B-17 from Port Moresby. From the air they saw the burnt and cleared fields by the Lunga, but spotted no beach defences. That observation proved correct.

The directive of 2 July

The American decision to take the offensive was made independently of the Japanese airfield, although that airfield eventually determined its main objective. After the victory at Midway, Washington and Australia agreed that the advantage had to be exploited quickly, before the Japanese could rebuild their strength. The dispute was over where to strike and under whose command. On 8 June General Douglas MacArthur, commander of the South West Pacific Area, proposed a bold thrust straight at Rabaul, the main Japanese base on New Britain, if he were given a division trained in amphibious warfare and two carriers. Admiral Ernest King, Commander-in-Chief of the United States Fleet and Chief of Naval Operations, wanted instead to advance step by step, starting with Tulagi and the Santa Cruz Islands, with the navy in command. He had no intention of handing an army general the carriers, of which after Midway the navy had only four in the Pacific, and he feared that MacArthur would take them into the confined waters between the Solomons and New Guinea, within range of Japanese land-based aircraft. On 25 June King presented his plan to the Army Chief of Staff, General George Marshall, and at once told Admiral Chester Nimitz to begin preparations, making it clear that the navy would strike alone if need be.

Marshall and King negotiated from 29 June. On 2 July 1942 they signed a joint directive of the Joint Chiefs of Staff on offensive operations in the south-west Pacific. The ultimate objective was the New Britain–New Ireland–New Guinea area, and the operation was divided into three tasks. Task One, the seizure of the Santa Cruz Islands, Tulagi and “adjacent positions”, was to be carried out by a commander designated by Nimitz, with a target date of 1 August. Task Two – the rest of the Solomons together with Lae, Salamaua and the north-east coast of New Guinea – and Task Three, the capture of Rabaul, were assigned to MacArthur. To settle the command dispute, the boundary between the two areas was moved, with effect from 1 August, to the 159th meridian east. As a result Tulagi, Guadalcanal and the neighbouring islands fell within the South Pacific Area, under the navy. The first version of the directive did not even mention Guadalcanal by name. When in the first days of July Nimitz discussed the plan at Pearl Harbor with Vice Admiral Frank Jack Fletcher and Rear Admiral Richmond Turner, the Japanese airfield was already known about, and it was proposed that the island be added to the operation’s objectives.

Ghormley and Vandegrift

Task One fell to Vice Admiral Robert Ghormley, who had taken command of the South Pacific Area in Auckland on 19 June. Fletcher was to command the whole expeditionary force, with three carriers, and Turner the amphibious force. On 7 July Ghormley flew to Melbourne for talks with MacArthur. The two agreed that not only Tulagi but also the airfield on Guadalcanal had to be taken, but they sent a warning to Washington: the forces were too small, the amphibious fleet would have to lie for several days without land-based air cover, and Rabaul remained untouched. They recommended postponing Task One until all three could be carried out in a single sequence. On 10 July the chiefs of staff refused: the Japanese advance in the Solomons had to be stopped immediately, and Nimitz and the army promised to send more ships and B-17 bombers.

The striking force was to be the 1st Marine Division under Major General Alexander Vandegrift. The division was only just arriving in New Zealand, where it was to train until at least early 1943. Its headquarters and the 5th Marine Regiment reached Wellington on 14 June, and the second echelon was still at sea when on 26 June Ghormley summoned Vandegrift to Auckland and told him that in little more than a month the division was to land in the Solomons. The second echelon arrived on 11 July. The ships had come with their cargo stowed for convenience of transport rather than for combat, so the men themselves, in the rain, unloaded them on the Wellington quay and loaded them again so that weapons and ammunition would come ashore first. The division had no good maps, knew little about the island and estimated the enemy’s strength at several thousand men. On 16 July Ghormley set the landing for 7 August; no further delay could be risked, since the Japanese were finishing the airfield. On 22 July Turner’s convoy sailed from Wellington, and in the last days of July landing rehearsals were held off the island of Koro in Fiji, which Vandegrift himself later judged very harshly. Because of the haste and the shortages, the operation, code-named Watchtower, was nicknamed Operation Shoestring in the staffs – one run on a shoestring.

Place in the war

On 7 August 1942 the Marines landed simultaneously on Guadalcanal and on Tulagi, Gavutu and Tanambogo. On Guadalcanal the Americans met almost no resistance: after the bombardment from ships and aircraft Monzen’s men fled west, leaving behind equipment, food and an almost finished airfield. The Americans completed it with Japanese machinery and named it Henderson Field after a Marine aviator killed at Midway. Martin Clemens came down from the mountains and placed his scouts at Vandegrift’s disposal. Japan, however, had no intention of accepting the loss. As early as the night of 8–9 August Mikawa’s cruisers shattered the Allied screening force off Savo Island, and the Japanese high command began moving more and more army units to the island.

So began the six-month Guadalcanal campaign, a series of land, sea and air battles in which Japan lost dozens of ships, hundreds of aircraft with trained crews and tens of thousands of soldiers, many of them to hunger and disease. In early February 1943 the Japanese evacuated what remained of their forces. The airfield on the Lunga, which in July 1942 was meant to be another link in Japan’s defensive perimeter, became the place where the United States first went over to the attack and where the initiative in the Pacific finally passed into its hands. The directive of 2 July also set the course of the next two years of the war: a slow march through the Solomons and New Guinea towards Rabaul, conducted by two rival commands, the navy’s and MacArthur’s.