The Guadalcanal campaign, also known as the Battle of Guadalcanal and codenamed Operation Watchtower by the United States, was an Allied offensive against forces of the Empire of Japan in the Solomon Islands during the Pacific Theater of World War II. It was fought between 7 August 1942 and 9 February 1943, and involved major land and naval battles on and surrounding the island of Guadalcanal. It was the first major Allied land offensive against Japan during the war.
In summer 1942, the Allies decided to mount major offensives in New Guinea and the Solomon Islands with the objectives of defending sea lines to Australia and eventually attacking the major Japanese base at Rabaul on New Britain. The Guadalcanal operation was under the command of Robert L. Ghormley, reporting to Chester W. Nimitz, while the Japanese defense consisted of the Combined Fleet under Isoroku Yamamoto and the Seventeenth Army under Harukishi Hyakutake.
On 7 August 1942, Allied forces, predominantly U.S. Marines, landed on Guadalcanal, Tulagi, and Florida Island in the southern Solomon Islands. The Japanese defenders, who had occupied the islands since May 1942, offered little initial resistance, but the capture of Guadalcanal soon turned into a lengthy campaign as both sides added reinforcements. The Allies captured and completed Henderson Field on Guadalcanal and established a defense perimeter. The Japanese made several attempts to retake the airfield, including in mid-September and in late October. The campaign also involved major naval battles, including the Battles of Savo Island, the Eastern Solomons, Cape Esperance, and the Santa Cruz Islands, culminating in a decisive Allied victory at the Naval Battle of Guadalcanal in mid-November. Further engagements took place at the Battle of Tassafaronga and Battle of Rennell Island. In December, the Japanese decided to abandon Guadalcanal to focus on the defense of the other Solomon Islands, and evacuated their last forces by 9 February 1943.
The campaign followed the successful Allied defensive actions at the Battle of the Coral Sea and the Battle of Midway in May and June 1942. Along with the battles at Milne Bay and Buna–Gona on New Guinea, the Guadalcanal campaign marked the Allies' transition from defensive operations to offensive ones, and effectively allowed them to seize the strategic initiative in the Pacific theater from the Japanese. The campaign was followed by other major Allied offensives in the Pacific, most notably: the Solomon Islands campaign, New Guinea campaign, the Gilbert and Marshall Islands campaign, the Mariana and Palau Islands campaign, the Philippines campaign of 1944 to 1945, and the Volcano and Ryukyu Islands campaign prior to the surrender of Japan in August 1945.
Background
Strategic considerations
On 7 December 1941, Japanese forces attacked the United States Pacific Fleet at Pearl Harbor, Hawaii. The attack killed almost 2,500 and crippled much of the U.S. battleship fleet, precipitating formal declarations of war between the two nations the next day. The initial goals of the Japanese leadership were to neutralize the U.S. Navy, seize territories rich in natural resources, and establish strategic military bases with which to defend Japan's empire in the Pacific Ocean and Asia. Initially, Japanese forces captured the Philippines, Thailand, Malaya, Singapore, Burma, the Dutch East Indies, Wake Island, Gilbert Islands, New Britain and Guam. The U.S. was joined in the war against Japan by several of the Allied powers, including the British Empire and the Dutch government-in-exile, both of which had also been attacked by Japan.
The Japanese made two attempts to continue their offensive and extend their outer defensive perimeter in the south and central Pacific to a point at which they could threaten Australia, Hawaii, and the U.S. west coast. The first offensive was thwarted in the naval Battle of the Coral Sea, which was a tactical stalemate but a strategic Allied victory in that it checked Japan's expansion across the Pacific for the first time: it was the Allies' first major victory against the Japanese and significantly reduced the offensive capability of Japan's carrier forces.
However, the battle did not temper Japan's audacious offensive military posture for several crucial months, with Japanese forces attempting a failed attack on Port Moresby over the Kokoda track. The second major Japanese offensive was stopped at the Battle of Midway. Both sides suffered significant losses in carrier aircraft and aircrew during these engagements. Crucially, while the Americans were able to reconstitute their naval air strength in relatively short order, Japanese limitations in industrial and pilot training capacity meant combat losses rapidly outpaced replacement men and matériel. These strategic victories allowed the Allies to transition to a more offensive stance in the Pacific theater, and attempt to seize the strategic initiative from Japan.
The Allies chose the Solomon Islands (a protectorate of the United Kingdom), specifically the southern islands of Guadalcanal, Tulagi and Florida Island, as their first target, designated Task One (codename Pestilence), with the initial objectives of occupying the Santa Cruz Islands (codename Huddle), Tulagi (codename Watchtower), and "adjacent positions". Guadalcanal (codename Cactus), which eventually became the focus of the operation, was not even mentioned in the early directive, and only later took on the operation name Watchtower. Tulagi, although small, had a large natural harbor that was ideal for a float-plane base; Florida Island also had to be taken, as it dominated Tulagi. Guadalcanal, much larger than the other two islands and located to the south across the soon-to-be-named Ironbottom Sound, was added when it was discovered the Japanese were constructing an airbase there.
The Imperial Japanese Navy (IJN) had occupied Tulagi in May 1942 and had constructed a seaplane base nearby. Allied concern grew when, in early July, the IJN began constructing a large airfield at Lunga Point on nearby Guadalcanal. From such a base, Japanese long-range bombers could threaten the sea lines of communication and maritime trade and transportation routes from the west coast of the Americas to the populous east coast of Australia. By August, the Japanese had about 900 naval troops on Tulagi and nearby islands, and 2,800 personnel (including 2,200 Korean forced laborers and trustees, as well as Japanese construction specialists) on Guadalcanal. These bases were meant to protect Japan's major naval base at Rabaul, threaten Allied supply and communication lines, and establish a staging area for a planned offensive against Fiji, New Caledonia and Samoa (Operation FS). The Japanese planned to deploy 45 fighters and 60 bombers to Guadalcanal. In the overall strategy for 1942, these aircraft would provide ground-based air cover for Japanese naval forces advancing farther into the South Pacific.
The Allied plan to invade the southern Solomons was conceived by U.S. Admiral Ernest King, Commander in Chief, United States Fleet. He proposed the offensive in order to deny the use of the islands to the Japanese as bases from which the supply routes between the United States and Australia could be threatened, and to use them as starting points for further Allied offensives in the South Pacific. With U.S. President Franklin D. Roosevelt's tacit consent, King also advocated for an invasion of Guadalcanal. Due to the Roosevelt administration's support for Great Britain's proposal that priority be given to defeating Germany before Japan, Allied commanders in Pacific theater had to compete for personnel and resources with the European theater.
An early obstacle was the desire of both the U.S. Army and the Roosevelt administration to initiate offensive action in Europe prior to a large-scale operation in the Pacific. In addition, it was initially unclear who would command the campaign: Tulagi lay in the area under the command of General Douglas MacArthur, whereas the Santa Cruz Islands lay in Admiral Chester W. Nimitz's Pacific Ocean Area, which would also supply almost all Allied offensive forces that would be staged, supplied and covered from that area. Both problems were overcome, and the Chief of Staff of the U.S. Army, General George C. Marshall, gave the operation his full support, despite MacArthur's command being unable to directly assist in the operation and the U.S. Navy taking full operational responsibility. As a result, and in order to preserve the unity of command, the boundary between MacArthur's South West Pacific Area and Nimitz's Pacific Ocean Area was shifted 60 miles (97 km) to 360 miles (580 km) to the west, effective from 1 August 1942.
Chief of Staff to the Commander in Chief William D. Leahy established two goals for 1942–1943: first, that Guadalcanal would be taken, in conjunction with an Allied offensive in New Guinea under MacArthur; and second, that the Admiralty Islands and Bismarck Archipelago, including the major Japanese base at Rabaul, would be captured as well. The directive held that the eventual goal was the American reconquest of the Philippines, from which American forces had been evicted in early 1942. The U.S. Joint Chiefs of Staff created the South Pacific theater, with Vice Admiral Robert L. Ghormley taking command on 19 June, to direct the offensive in the Solomons. Nimitz, based at Pearl Harbor, was designated as overall Allied commander-in-chief for Allied forces in the Pacific.
Task force
In preparation for the offensive in the Pacific in May 1942, U.S. Marine Major General Alexander Vandegrift was ordered to move his 1st Marine Division from the United States to New Zealand. Other Allied land, naval and air units were sent to establish or reinforce bases in Fiji, Samoa, New Hebrides and New Caledonia.
The island of Espiritu Santo, in the New Hebrides, was selected as the headquarters and primary staging ground for the offensive, codenamed Operation Watchtower, with the commencement date set for 7 August. At first, only the seizure of Tulagi and the Santa Cruz Islands was planned, omitting a landing on Guadalcanal. After Allied reconnaissance discovered Japanese airfield construction efforts on Guadalcanal, its capture was added to the plan, and planned landings on the Santa Cruz islands were (eventually) abandoned. The Japanese were aware, via signals intelligence, of the large-scale movement of Allied forces in the South Pacific Area, but concluded that the Allies were reinforcing either Australia or Port Moresby on the southern coast of New Guinea.
The Watchtower force, numbering 75 warships and transports (including vessels from the U.S. and Australia), assembled near Fiji on 26 July and conducted a single rehearsal landing prior to leaving for Guadalcanal on 31 July. The commander of the Allied expeditionary force was U.S. Vice Admiral Frank Fletcher, Commander of Task Force 16 (whose flag was on the aircraft carrier USS Saratoga). Commanding the amphibious forces was U.S. Rear Admiral Richmond K. Turner. Vandegrift led the 16,000 Allied (primarily U.S. Marine) infantry earmarked for the amphibious landings. The troops sent to Guadalcanal were fresh from military training, armed with legacy bolt-action M1903 Springfield rifles and a meager 10-day supply of ammunition. Because of the need to get the troops into battle quickly, the Allied planners had reduced their supplies from 90 days to only 60. The men of the 1st Marine Division began referring to the coming battle as "Operation Shoestring".
Events
Landings
Bad weather allowed the Allied expeditionary force to arrive unseen by the Japanese on the night of 6 August and morning of 7 August, taking the defenders by surprise. This is occasionally referred to as the "Midnight Raid on Guadalcanal". A Japanese patrol aircraft from Tulagi had searched the general area that the Allied invasion fleet was moving through, but was unable to spot the Allied fleet due to severe storms and heavy clouds. The landing force split into two groups, with one group assaulting Guadalcanal and the other Tulagi, Florida, and other nearby islands. Allied warships bombarded the invasion beaches, while U.S. carrier aircraft bombed Japanese positions on the target islands and destroyed 15 Japanese seaplanes at their base near Tulagi.
Tulagi and two nearby small islands, Gavutu and Tanambogo, were assaulted by 3,000 U.S. Marines under the command of Brigadier General William Rupertus. The 886 IJN personnel manning the naval and seaplane bases on the three islands fiercely resisted the Marine landings. With some difficulty, the Marines secured all three islands: Tulagi on 8 August, and Gavutu and Tanambogo by 9 August. The Japanese defenders were killed almost to the last man, and the Marines suffered 248 casualties.
In contrast to Tulagi, Gavutu, and Tanambogo, the landings on Guadalcanal encountered much less resistance. At 09:10 on 7 August, Vandegrift and 11,000 U.S. Marines came ashore on Guadalcanal between Koli Point and Lunga Point. Advancing towards Lunga Point, they encountered scant Japanese resistance and secured the airfield by 16:00 on 8 August. The Japanese naval construction units and combat troops, under the command of Captain Kanae Monzen, had panicked after coming under naval bombardment and aerial bombing, and had abandoned the airfield and fled about 3 miles (5 km) west to the Matanikau River and Point Cruz area. Japanese troops left behind food, supplies, intact construction equipment and vehicles, and 13 dead at the airfield and surrounding area.
During the landing operations on 7 and 8 August, Rabaul-based Japanese naval aircraft under the command of Yamada Sadayoshi attacked the Allied amphibious forces several times, setting on fire the transport USS George F. Elliott, which sank two days later, and heavily damaging the destroyer USS Jarvis. Over the course of two days of air attacks, Japanese air units lost 36 aircraft, while the U.S. lost 19 (including 14 carrier aircraft), both in combat and to accidents.