Operation Ke
Operation Ke was the largely successful withdrawal of Japanese forces from Guadalcanal, concluding the Guadalcanal Campaign of. The operation took place between 14 January and 7 February 1943, and involved both Imperial Japanese Army and Imperial Japanese Navy forces under the overall direction of the Japanese Imperial General Headquarters. Commanders of the operation included Isoroku Yamamoto and Hitoshi Imamura.
The Japanese decided to withdraw and concede Guadalcanal to Allied forces for several reasons. All attempts by the IJA to recapture Henderson Field, the airfield on Guadalcanal in use by Allied aircraft, had been repulsed with heavy losses. Japanese ground forces on the island had been reduced from 36,000 to 11,000 through starvation, disease, and battle casualties. IJN forces were also suffering heavy losses attempting to reinforce and resupply the ground forces on the island. These losses, plus the projected resources needed for further attempts to recapture Guadalcanal, were affecting strategic security and operations in other areas of the Japanese Empire. The decision to withdraw was endorsed by Emperor Hirohito on 31 December 1942.
The operation began on 14 January 1943 with the delivery of a battalion of infantry troops to Guadalcanal to act as rearguard for the evacuation. Around the same time, IJA and IJN air forces began an air superiority campaign around the Solomon Islands and New Guinea. During the air campaign, a US cruiser was sunk in the Battle of Rennell Island and one of its escorting destroyers was heavily damaged by torpedo bombing. Two days later, Japanese dive bombers sank a US destroyer off Verahue and damaged another, and Japanese R Area Airforce floatplanes mounted an effective reconnaissance operation around Guadalcanal that spotted most allied naval units operating in the area. The withdrawal was carried out in three runs on the nights of 1, 4, and 7 February by destroyers.
At a cost of one destroyer sunk and three damaged, the Japanese evacuated 10,652 men from Guadalcanal. During the evacuation 600 died and 3,000 more required extensive hospital care. On 9 February, Allied forces realized that the Japanese were gone and declared Guadalcanal secure, ending the six-month campaign for control of the island.
Background
Guadalcanal Campaign
On 7 August 1942, the US 1st Marine Division landed on Guadalcanal, Tulagi, and Florida Islands in the Solomon Islands. The landings on the islands were meant to deny their use by the Japanese as bases for threatening the supply routes between the US and Australia, and to secure the islands as starting points for a campaign with the eventual goal of capturing or neutralizing the major Japanese base at Rabaul while also supporting the Allied New Guinea campaign. The landings initiated the six-month-long Guadalcanal campaign.Taking the Japanese by surprise, by nightfall on 8 August the Marines secured Tulagi and nearby islands as well as the Japanese airfield under construction at Lunga Point on Guadalcanal. The Allies later renamed it "Henderson Field". Allied aircraft operating out of Henderson were called the "Cactus Air Force" after the Allied code name for Guadalcanal.
In response to the landings on Guadalcanal, the Japanese Imperial General Headquarters assigned the Imperial Japanese Army's 17th Army, a corps-sized command headquartered at Rabaul under the command of Lieutenant General Harukichi Hyakutake, the task of retaking Guadalcanal. Because of the threat by CAF aircraft, the Imperial Japanese Navy was unable to use large, slow transport ships to deliver troops and supplies to the island. Instead, warships based at Rabaul and the Shortland Islands were used to carry forces to Guadalcanal. The Japanese warships, mainly light cruisers and destroyers from the Eighth Fleet under the command of Vice Admiral Gunichi Mikawa, were usually able to make the round trip down "The Slot" to Guadalcanal and back in a single night, thereby minimizing their exposure to CAF air attack. These high speed warship runs to Guadalcanal occurred throughout the campaign and were later called the "Tokyo Express" by Allied forces and "Rat Transportation" by the Japanese.
File:RabaulStrategicArea.jpg|thumb|left|The Solomon Islands area in the south Pacific. The Japanese base at Rabaul is at the upper left. Guadalcanal lies at the southeastern end of "The Slot".
Using forces delivered to Guadalcanal in this manner, the IJA tried three times to retake Henderson Field, but was defeated each time. After the third failure, an attempt by the IJN to deliver the rest of the IJA 38th Infantry Division and its heavy equipment failed during the Naval Battle of Guadalcanal from 12 to 15 November. Because of this failure, the Japanese cancelled their next planned attempt to recapture Henderson Field.
In mid-November, Allied forces attacked the Japanese at Buna-Gona in New Guinea. Japanese Combined Fleet naval leaders, headquartered at Truk and under the overall command of Admiral Isoroku Yamamoto, felt Allied advances in New Guinea posed a greater threat to the security of the Japanese Empire than an Allied military presence in the southern Solomons. Therefore, Combined Fleet naval staff officers began to prepare plans for abandoning Guadalcanal and shifting priorities and resources to operations around New Guinea. At this time, the navy did not inform the army of their intentions in this regard.
As December began, the Japanese experienced considerable difficulty in keeping their troops on Guadalcanal resupplied because of Allied air and naval attacks on the Japanese supply chain of ships and bases. The few supplies delivered to the island were not enough to sustain Japanese troops who, by 7 December, were losing about 50 men each day to malnutrition, disease, and Allied ground or air attacks. The Japanese had delivered almost 30,000 army troops to Guadalcanal since the campaign began, but by December only about 20,000 of that number were still alive; of those, only around 12,000 remained more or less fit for combat duty, with the rest incapacitated by battle wounds, disease, or malnutrition.
The IJN continued to suffer losses and damage to its ships in attempting to keep the Japanese on Guadalcanal resupplied. One destroyer was sunk by American warships at the Battle of Tassafaronga on 30 November. Another destroyer plus a submarine were sunk and two destroyers damaged by American PT boat and CAF air attacks during subsequent resupply missions from 3–12 December. Compounding the navy's frustration, very few of the supplies carried on these missions reached IJA forces on the island. Combined Fleet leaders began telling their army counterparts the losses and damage to warships engaged in the resupply effort threatened future strategic plans for protecting the Japanese Empire.
Decision to withdraw
Throughout November, Japan's top military leaders at the IGH in Tokyo continued to openly support further efforts to retake Guadalcanal from Allied forces. At the same time, lower-ranking staff officers began to discreetly discuss abandoning the island. Takushiro Hattori and Masanobu Tsuji, each of whom had recently visited Guadalcanal, told their colleagues on the staff that any further attempt to retake the island was a lost cause. Ryūzō Sejima reported that the attrition of IJA troop-strength on Guadalcanal was so unexpectedly severe that future operations would be untenable. On 11 December two staff officers, IJN Commander Yuji Yamamoto and IJA Major Takahiko Hayashi, returned to Tokyo from Rabaul and confirmed Hattori's, Tsuji's, and Sejima's reports. They further reported that most of the IJN and IJA officers at Rabaul appeared to support abandoning Guadalcanal. Around this time, Japan's War Ministry informed the IGH that there was insufficient shipping to support both the effort to retake Guadalcanal and transport strategic resources to maintain Japan's economy and military forces.On 19 December, a delegation of IGH staff officers led by IJA Colonel Joichiro Sanada, chief of the IGH's operations section, arrived at Rabaul for discussions about future plans concerning New Guinea and Guadalcanal. Hitoshi Imamura, commander of the 8th Area Army in charge of IJA operations in New Guinea and the Solomons, did not directly recommend a withdrawal from Guadalcanal but openly and clearly described the current difficulties involved with any further attempts to retake the island. Imamura also stated that any decision to withdraw should include plans to evacuate as many of the soldiers from Guadalcanal as possible.
Sanada returned to Tokyo on 25 December and recommended to the IGH that Guadalcanal be abandoned immediately and all priority given to the campaign in New Guinea. The IGH's top leaders agreed with Sanada's recommendation on 26 December and ordered their staffs to begin drafting plans for the withdrawal from Guadalcanal and establishment of a new defense line in the central Solomons.
On 28 December, General Hajime Sugiyama and Admiral Osami Nagano personally informed Emperor Hirohito of the decision to withdraw from Guadalcanal. On 31 December, the Emperor formally endorsed the decision.
Plan and forces
On 3 January, IGH informed the 8th Area Army and the Combined Fleet of the decision to withdraw from Guadalcanal. By 9 January, the Combined Fleet and 8th Area Army staffs together completed the plan, officially called Operation Ke after a mora in Japanese Kana vocabulary, to execute the evacuation.The plan called for a battalion of IJA infantry to land by destroyer on Guadalcanal around 14 January to act as a rear guard during the evacuation. The 17th Army was to begin withdrawing to the western end of the island about 25 or 26 January. An air superiority campaign around the southern Solomons would begin on 28 January. The 17th Army would be picked up in three lifts by destroyers the first week of February with a target completion date of 10 February. At the same time, Japanese air and naval forces would conduct conspicuous maneuvers and minor attacks around New Guinea and the Marshall Islands along with deceptive radio traffic to try to confuse the Allies as to their intentions.
Yamamoto detailed aircraft carriers and, battleships and – with four heavy cruisers and a destroyer as the screening force – under Nobutake Kondō to provide distant cover for Ke around Ontong Java in the northern Solomons. The evacuation runs were to be carried out by Mikawa's 8th Fleet; the Reinforcement Unit and R area force, consisting of the support unit of the heavy cruisers and and light cruiser which would remain at Kavieng, and 21 destroyers gathered at the Shortlands, which would conduct the transportation of troops. RADM. Satuma Kimura, one of the finest destroyer flotilla commanders in the navy at the time, would command the Reinforcement Unit, but he was wounded when his destroyer Akizuki was damaged by a submarine torpedo on January 19 off the Shortlands. Command of the Reinforcement Unit was then shifted to RADM. Koyanagi, though Koyanagi was in turn shortly replaced by the recently promoted RADM. Shintarō Hashimoto as commander of the Reinforcement Unit for Operation KE. Yamamoto expected that at least half of Mikawa's destroyers would be sunk during the operation.
Supporting the air superiority portion of the operation were the IJN's 11th Air Fleet and the IJA's 6th Air Division, based at Rabaul with 212 and 100 aircraft, respectively. 64 aircraft from carrier s air group were also temporarily assigned to Rabaul. An additional 60 floatplanes from the IJN's "R" Area Air Force, based at Rabaul, Bougainville and the Shortland Islands, brought the total number of Japanese aircraft involved in the operation to 436. The combined Japanese warship and naval air units in the area formed the Southeast Area Fleet, commanded by Jinichi Kusaka at Rabaul.
Opposing the Japanese and under the command of United States Navy Admiral William Halsey Jr., commander of Allied forces in the South Pacific, were fleet carriers and, six escort carriers, three fast battleships, four old battleships, 13 cruisers, and 45 destroyers. In the air, the 13th Air Force numbered 92 fighters and bombers under United States Army Brigadier General Nathan F. Twining and the CAF on Guadalcanal counted 81 aircraft under US Marine Brigadier General Francis P. Mulcahy. Rear Admiral Aubrey Fitch was overall commander of Aircraft South Pacific. The air units of the fleet and escort carriers added another 339 aircraft. In addition, 30 heavy bombers were stationed in New Guinea with sufficient range to conduct missions over the Solomon Islands. In total, the Allies possessed around 539 aircraft available to oppose the Ke operation.
By the first week of January, disease, starvation, and battle had reduced Hyakutake's command to about 14,000 troops, with many of them too sick and malnourished to fight. The 17th Army possessed three operable field cannon, with very little ammunition. In contrast, the Allied commander on the island, US Army Major General Alexander Patch, fielded a combined force of US Army and US Marines, designated the XIV Corps, totaling 50,666 men. At Patch's disposal were 167 artillery weapons, including M116 howitzer|, M101 howitzer|, and M114 155 mm howitzer| howitzers, and plentiful stocks of shells.