Guadalcanal campaign

For six months, from August 1942 to February 1943, Allied and Japanese forces fought for control of Guadalcanal, a jungle island in the southern Solomon Islands, and of the seas and skies around it. The campaign, codenamed Operation Watchtower by the Americans, was the first major Allied land offensive against Japan in the Pacific War. It ended with a Japanese withdrawal, and after it the strategic initiative in the Pacific passed permanently to the Allies.

After the battles of the Coral Sea and Midway in May and June 1942 had checked Japan's advance, Admiral Ernest King pressed for an offensive to protect the sea routes between the United States and Australia. The Japanese had occupied Tulagi in May and in July began building an airfield at Lunga Point on Guadalcanal, from which bombers could threaten those routes. The Allies resolved to seize the islands as a first step towards Japan's base at Rabaul.

On 7 August 1942 about 16,000 Allied troops, mostly of the 1st Marine Division under Major General Alexander Vandegrift, landed on Guadalcanal, Tulagi and nearby islands. On Guadalcanal the Japanese construction troops and their guards fled, and the Marines took the unfinished airfield, which they named Henderson Field. On the night of 8–9 August a Japanese cruiser force surprised the Allied screening ships at the Battle of Savo Island, sinking four cruisers. The Allied transports withdrew, leaving the Marines short of food and equipment.

The struggle became a contest of reinforcement. By night, Japanese destroyers, nicknamed the "Tokyo Express" by the Americans, ran troops down the channel known as the Slot; by day, aircraft from Henderson Field, the "Cactus Air Force", controlled the surrounding waters. Japanese attacks on the Marine perimeter failed repeatedly: Colonel Ichiki's advance force was almost wiped out at the Tenaru in August, Kawaguchi's brigade was thrown back at Edson's Ridge in September, and in late October a larger offensive by the 2nd Division was defeated with the loss of perhaps 2,200 to 3,000 Japanese soldiers. In mid-October Japanese battleships bombarded the airfield, destroying around half its aircraft. Solomon Islander scouts such as Jacob Vouza gave the defenders vital warnings.

At sea the two navies fought a series of costly battles. The carrier action of the Eastern Solomons in August cost Japan a light carrier, and at Cape Esperance in October an American cruiser force won a night engagement. At the Santa Cruz Islands later that month the US Navy lost the carrier Hornet, but Japan lost many experienced aircrew. The decisive clash came in the Naval Battle of Guadalcanal from 12 to 15 November, when Japanese efforts to bombard the airfield and land a large convoy were defeated: Japan lost two battleships, and all eleven transports of the convoy were sunk or destroyed, so that only 2,000 to 3,000 of its troops got ashore. Japanese destroyers still won a sharp night action at Tassafaronga on 30 November, but the garrison was starving.

On 31 December the Emperor approved abandoning the island. In January 1943, as fresh US Army and Marine units under General Alexander Patch cleared Mount Austen and nearby ridges, Japanese commanders prepared Operation Ke, and on three nights in early February destroyers evacuated 10,652 men. The last left on 7 February, and on 9 February Patch declared the island secure.

About 7,100 Allied servicemen were killed, and both navies lost dozens of ships and hundreds of aircraft. Japanese deaths are variously put at around 19,000 to 30,000, most of them from starvation and tropical disease rather than combat. Japan could not replace the aircrews, ships and veteran troops it lost. Together with the battles in New Guinea, the campaign marked the turning of the tide in the Second World War in the Pacific.

Our 1938 map shows the Pacific before the war, when the Solomon Islands were a British protectorate, and the 1945 map shows the Pacific at the end of the war, after the collapse of the Empire of Japan. The islands are today the independent Solomon Islands.