The Matanikau Offensive, from 1–4 November 1942, sometimes referred to as the Fourth Battle of the Matanikau, was an engagement between United States (U.S.) Marine and Army and Imperial Japanese Army forces around the Matanikau River and Point Cruz area on Guadalcanal during the Guadalcanal campaign of World War II. The action was one of the last of a series of engagements between U.S. and Japanese forces near the Matanikau River during the campaign.
In the engagement, seven battalions of U.S. Marine and Army troops under the overall command of Alexander Vandegrift and tactical command of Merritt A. Edson, following up on the U.S. victory in the Battle for Henderson Field, crossed the Matanikau River and attacked Japanese Army units between the river and Point Cruz, on the northern Guadalcanal coast. The area was defended by the Japanese Army's 4th Infantry Regiment under Nomasu Nakaguma along with various other support troops, under the overall command of Harukichi Hyakutake. After inflicting heavy casualties on the Japanese defenders, U.S. forces halted the offensive and temporarily withdrew because of a perceived threat from Japanese forces elsewhere in the Guadalcanal area.
Background
Guadalcanal campaign
On 7 August 1942, Allied forces (primarily U.S.) 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 U.S. and Australia, and to secure the islands as starting points for a campaign with the eventual goal of isolating the major Japanese base at Rabaul while also supporting the Allied New Guinea campaign. The landings initiated the six-month-long Guadalcanal campaign.Hogue, Pearl Harbor to Guadalcanal, pp. 235–36.
Taking the Japanese by surprise, by nightfall on 8August the 11,000 Allied troops, under the command of Lieutenant General Alexander Vandegrift and mainly consisting of United States Marine Corps units, had secured Tulagi and nearby small islands, as well as an airfield under construction at Lunga Point on Guadalcanal. The airfield was later named Henderson Field by Allied forces. The Allied aircraft that subsequently operated out of the airfield became known as the "Cactus Air Force" (CAF) after the Allied codename for Guadalcanal. To protect the airfield, the U.S. Marines established a perimeter defense around Lunga Point.Morison, Struggle for Guadalcanal, pp. 14–15; Shaw, First Offensive, p. 18.
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 from Allied forces. Beginning on 19 August, various units of the 17th Army began to arrive on Guadalcanal with the goal of driving Allied forces from the island.Griffith, Battle for Guadalcanal, pp. 96–99; Dull, Imperial Japanese Navy, p. 225; Miller, Guadalcanal: The First Offensive, pp. 137–38.
Because of the threat by CAF aircraft based at Henderson Field, the Japanese were unable to use large, slow transport ships to deliver troops and supplies to the island. Instead, the Japanese used warships based at Rabaul and the Shortland Islands to carry their forces to Guadalcanal. The Japanese warships, mainly light cruisers or 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. Delivering the troops in this manner, however, prevented most of the soldiers' heavy equipment and supplies, such as heavy artillery, vehicles, and much food and ammunition, from being carried to Guadalcanal with them. 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.Frank, Guadalcanal, pp. 202, 210–11.
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 to 14 September, with the 6,000 soldiers under the command of Major General Kiyotake Kawaguchi being defeated in the Battle of Edson's Ridge. After their defeat at Edson's Ridge, Kawaguchi and the surviving Japanese troops regrouped west of the Matanikau River on Guadalcanal.Frank, Guadalcanal, pp. 141–43, 156–58, 228–46, 681.
As the Japanese regrouped, the U.S. forces concentrated on shoring up and strengthening their Lunga defenses. On 18 September, an Allied naval convoy delivered 4,157 men from the U.S. 7th Marine Regiment to Guadalcanal. These reinforcements allowed Vandegrift, beginning on 19 September, to establish an unbroken line of defense completely around the Lunga perimeter.Griffith, Battle for Guadalcanal, p. 156; Smith, Bloody Ridge, pp. 198–200.
General Vandegrift and his staff were aware that Kawaguchi's troops had retreated to the area west of the Matanikau and that numerous groups of Japanese stragglers were scattered throughout the area between the Lunga Perimeter and the Matanikau River. Vandegrift therefore decided to conduct a series of small unit operations around the Matanikau valley.Smith, Bloody Ridge, p. 204; Frank, Guadalcanal, p. 270.
The first U.S. Marine operation against Japanese forces west of the Matanikau, conducted between 23 September and 27 September 1942 by elements of three U.S. Marine battalions, was repulsed by Kawaguchi's troops under Colonel Akinosuke Oka's local command. In the second action, between 6October and October, a larger force of U.S. Marines successfully crossed the Matanikau River, attacked newly landed Japanese forces from the 2nd (Sendai) Infantry Division under the command of generals Masao Maruyama and Yumio Nasu and inflicted heavy casualties on the Japanese 4th Infantry Regiment. The second action forced the Japanese to retreat from their positions east of the Matanikau.Zimmerman, The Guadalcanal Campaign, pp. 96–101; Smith, Bloody Ridge, pp. 204–15; Frank, Guadalcanal, pp. 269–90; Griffith, Battle for Guadalcanal, pp. 169–76; Hough, Pearl Harbor to Guadalcanal, pp. 318–22. The 2nd Infantry was called Sendai because most of its soldiers were from Miyagi Prefecture.
In the meantime, Major General Millard F. Harmon, commander of United States Army forces in the South Pacific, convinced Vice Admiral Robert L. Ghormley, commander of Allied forces in the South Pacific Area, that U.S. Marine forces on Guadalcanal needed to be reinforced immediately if the Allies were to successfully defend the island from the anticipated Japanese offensive. Thus on 13 October, a naval convoy delivered the 2,837-strong 164th U.S. Infantry Regiment, an Army National Guard formation from the U.S. Army's Americal Division, to Guadalcanal.Frank, Guadalcanal, pp. 293–97; Morison, Struggle for Guadalcanal, pp. 147–49; Miller, Guadalcanal: The First Offensive, pp. 140–42; Dull, Imperial Japanese Navy, p. 225.
Battle for Henderson Field
Between 1 October and 17 October, the Japanese delivered 15,000 troops to Guadalcanal, giving Hyakutake 20,000 total troops to employ for his planned offensive. Because of the loss of their positions on the east side of the Matanikau, the Japanese decided that an attack on the U.S. defenses along the coast would be prohibitively difficult. Therefore, 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 Infantry Division), under Lieutenant General Masao Maruyama and comprising 7,000 soldiers in three infantry regiments of three battalions each was ordered to march through the jungle and attack the American defences from the south near the east bank of the Lunga River.Shaw, First Offensive, p. 34; Rottman, Japanese Army, p. 63. To distract the Americans from the planned attack from the south, Hyakutake's heavy artillery plus five battalions of infantry (about 2,900 men) from the 4th and 124th Infantry Regiments under the overall command of Major General Tadashi Sumiyoshi were to attack the American defenses from the west along the coastal corridor.Rottman, Japanese Army, p. 61; Frank, Guadalcanal, pp. 289–340; Hough, Pearl Harbor to Guadalcanal, pp. 322–30; Griffith, Battle for Guadalcanal, pp. 186–87; Dull, Imperial Japanese Navy, pp. 226–30; Morison, Struggle for Guadalcanal, pp. 149–71. The Japanese troops delivered to Guadalcanal during this time comprised the entire 2nd (Sendai) Infantry Division, two battalions from the 38th Infantry Division, and various artillery, tank, engineer, and other support units. Kawaguchi's forces also included what remained of the 3rd Battalion, 124th Infantry Regiment which was originally part of the 35th Infantry Brigade commanded by Kawaguchi during the Battle of Edson's Ridge.
Sumiyoshi's forces, including two battalions of the 4th Infantry Regiment under Colonel Nomasu Nakaguma, launched attacks on the U.S. Marine defenses at the mouth of the Matanikau on the evening of 23 October. U.S. Marine artillery, cannon, and small arms fire repulsed the assaults and killed many of the attacking Japanese soldiers while suffering only light casualties.Hough, Pearl Harbor to Guadalcanal, pp. 332–33; Frank, Guadalcanal, pp. 349–50; Rottman, Japanese Army, pp. 62–63; Griffith, Battle for Guadalcanal, pp. 195–96; Miller, Guadalcanal: The First Offensive, pp. 157–58. The Marines lost 2killed in the action. Japanese infantry losses are not recorded but were, according to Frank, "unquestionably severe." Griffith says that 600 Japanese soldiers were killed.
Beginning on 24 October and continuing over two consecutive nights, Maruyama's forces conducted numerous, unsuccessful frontal assaults on the southern portion of the U.S. Lunga perimeter. More than 1,500 of Maruyama's troops were killed in the attacks while the Americans lost about 60 killed.Hough, Pearl Harbor to Guadalcanal, p. 336; Frank, Guadalcanal, pp. 353–62; Griffith, Battle for Guadalcanal, pp. 197–204; Miller, Guadalcanal: The First Offensive, pp. 160–62; Miller, Cactus Air Force, pp. 147–51; Lundstrom, Guadalcanal Campaign, pp. 343–52.
Further Japanese attacks near the Matanikau on 26 October by Oka's 124th Infantry Regiment were also repulsed with heavy losses for the Japanese. Thus, at 08:00 on 26 October, Hyakutake called off any further attacks and ordered his forces to retreat. About half of Maruyama's survivors were ordered to retreat back to the area west of the Matanikau River while the rest, the 230th Infantry Regiment under Colonel Toshinari Shoji, was told to head for Koli Point, east of the Lunga perimeter. The 4th Infantry Regiment retreated back to positions west of the Matanikau and around the Point Cruz area while the 124th Infantry Regiment took up positions on the slopes of Mount Austen in the upper Matanikau Valley.Frank, Guadalcanal, pp. 363–406, 418, 424, 553; Zimmerman, Guadalcanal Campaign, pp. 122–23; Griffith, Battle for Guadalcanal, p. 204; Hough, Pearl Harbor to Guadalcanal, p. 337; Rottman, Japanese Army, p. 63.