Carlson's patrol, also known as The Long Patrol or Carlson's long patrol, was an operation by the 2nd Marine Raider Battalion under the command of Evans Carlson during the Guadalcanal campaign against the Imperial Japanese Army from 6 November to 4 December 1942. In the operation, the 2nd Raiders attacked forces under the command of Toshinari Shōji, which were escaping from an attempted encirclement in the Koli Point area on Guadalcanal and attempting to rejoin other Japanese army units on the opposite side of the U.S. Lunga perimeter.
In a series of small unit engagements over 29 days, the 2nd Raiders killed almost 500 Japanese soldiers while suffering 16 killed, although many were afflicted by disease. The Raiders also captured a Japanese field gun that was harassing Henderson Field, the Allied airfield at Lunga Point on Guadalcanal.
Background
Guadalcanal campaign
On 7 August 1942, Allied forces (primarily U.S. Marines) landed on Guadalcanal, Tulagi, and Florida Islands in the Solomon Islands. Their mission was to deny the Japanese use of the islands as bases for threatening the supply routes between the U.S. and Australia, and to secure the islands as starting points for a campaign to isolate the major Japanese base at Rabaul while also supporting the Allied New Guinea campaign. The landings initiated the six-month-long Guadalcanal campaign.
The Japanese were taken by surprise, and by nightfall on 8 August the 11,000 Allied troops—under the command of Lieutenant General Alexander Vandegrift—secured Tulagi and nearby small islands as well as an airfield under construction at Lunga Point on Guadalcanal. The Allies later renamed the airfield Henderson Field. To protect the airfield, the U.S. Marines established a perimeter defense around Lunga Point. Additional reinforcements over the next two months increased the number of U.S. troops at Lunga Point to more than 20,000.
In response to the Allied landings on Guadalcanal, the Japanese Imperial General Headquarters assigned the Imperial Japanese Army's 17th Army—a corps-sized command based at Rabaul and under the command of Lieutenant-General Harukichi Hyakutake—with the task of retaking Guadalcanal. Units of the 17th Army began to arrive on Guadalcanal on 19 August to drive Allied forces from the island.
The first Japanese attempt to recapture Henderson Field failed when a 917-man force was defeated on 21 August in the Battle of the Tenaru. The next attempt took place from 12–14 September, ending in the defeat of the 6,000 soldiers under the command of Major General Kiyotake Kawaguchi at the Battle of Edson's Ridge. Kawaguchi and the surviving Japanese troops then regrouped west of the Matanikau River on Guadalcanal.
Battle for Henderson Field
Between 1 and 17 October, the Japanese delivered 15,000 troops to Guadalcanal, giving Hyakutake 20,000 total troops to employ for his planned offensive. After his staff officers observed the American defenses around Lunga Point, Hyakutake decided that the main thrust of his planned attack would be from south of Henderson Field. His 2nd Division (augmented by troops from the 38th Division), under Lieutenant General Masao Maruyama was ordered to march through the jungle and attack the American defenses from the south near the east bank of the Lunga River. The 7,000-member 2nd Division was split into three units; the Left Wing Unit under Major General Yumio Nasu containing the 29th Infantry Regiment, the right wing unit under Kawaguchi consisting of troops from the 230th Infantry Regiment (from the 38th Infantry Division), and the division reserve led by Maruyama comprising the 16th Infantry Regiment.
On 23 October, Maruyama's forces struggled through the jungle to reach the American lines. Kawaguchi—on his own initiative—began to shift his right wing unit to the east, believing that the American defenses were weaker in that area. Maruyama, through one of his staff officers, ordered Kawaguchi to keep to the original attack plan. When he refused, Kawaguchi was relieved of command and replaced by Colonel Toshinari Shōji, commander of the 230th Infantry Regiment. That evening, after learning that the left and right wing forces were still struggling to reach the American lines, Hyakutake postponed the attack to 19:00 on 24 October. The Americans remained unaware of the approach of Maruyama's forces.