The Battle of Mount Austen, the Galloping Horse, and the Sea Horse, part of which is sometimes called the Battle of the Gifu, or the Battle of the Mountain of Blood among the Japanese, took place from 15 December 1942 to 23 January 1943 and was primarily an engagement between United States and Imperial Japanese forces in the hills near the Matanikau River area on Guadalcanal during the Guadalcanal campaign. The U.S. forces were under the overall command of Major General Alexander Patch and the Japanese forces were under the overall command of Lieutenant General Harukichi Hyakutake.
In the battle, U.S. soldiers and Marines, assisted by native Solomon Islanders, attacked Imperial Japanese Army forces defending well-fortified and entrenched positions on several hills and ridges. The most prominent hills were called Mount Austen, the Galloping Horse, and the Sea Horse by the Americans. The U.S. was attempting to destroy the Japanese forces on Guadalcanal, and the Japanese were trying to hold their defensive positions until reinforcements could arrive.
Both sides experienced extreme difficulties in fighting in the thick jungles and tropical environment of the battle area. Many American troops were also involved in their first combat operations. The Japanese were mostly cut off from resupply and suffered greatly from malnourishment and lack of medical care. After some difficulty, the U.S. succeeded in taking Mount Austen, in the process reducing a strongly defended position called the Gifu, as well as the Galloping Horse and the Sea Horse. In the meantime, the Japanese decided to abandon Guadalcanal and withdrew to the west coast of the island. From there most of the surviving Japanese troops were successfully evacuated during the first week of February 1943.
Background
Guadalcanal campaign Eight months after the beginning of the Pacific War, 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, pp. 235–236.
The Japanese were taken by surprise. By nightfall on 8 August, the 11,000 Allied troops—primarily from the 1st Marine Division of the United States Marine Corps under the command of Lieutenant General Alexander Vandegrift—secured Tulagi and nearby small islands as well as the Japanese airfield under construction at Lunga Point on Guadalcanal. The Allies later renamed the airfield Henderson Field. Allied aircraft operating out of Henderson were called the "Cactus Air Force" (CAF) after the Allied code name for Guadalcanal. To protect the airfield, the U.S. established a perimeter defense around Lunga Point. Additional reinforcements over the next two months increased the number of U.S. troops at Lunga Point on Guadalcanal to more than 20,000.Morison, pp. 14–15; Miller, p. 143; Frank, p. 338; and Shaw, 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. Units of the 17th Army began to arrive on Guadalcanal on 19 August to drive Allied forces from the island.Griffith, pp. 96–99; Dull, p. 225; Miller, pp. 137–138.
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 the Allies and "Rat Transportation" by the Japanese.Frank, pp. 202, 210–211.
Using forces delivered to Guadalcanal in this manner, the Japanese tried three times to retake Henderson Field, but they were defeated each time. First, a reinforced battalion from the 28th Infantry Regiment was defeated in the Battle of the Tenaru on 21 August. Next, the augmented 35th Infantry Brigade was defeated in the Battle of Edson's Ridge on 12–14 September. Finally, the 2nd Infantry Division augmented by one regiment from the 38th Infantry Division was defeated with heavy losses in the Battle for Henderson Field on 23–26 October.Frank, pp. 141–158, 218–246, 337–367.
Throughout the campaign, the Japanese used Mount Austen (called Bear Height by the Japanese and Mount Mambulu by the local Solomon Islanders), west of the Lunga River and about southwest of Henderson Field, to observe the American defenses around Lunga Point. Emplaced artillery on Mount Austen delivered harassing fire on Henderson Field. The hill was also used as a defensive point to protect their positions around the upper Matanikau valley as well as to protect the Maruyama Road, which was a trail used by the Japanese to move men and supplies into the interior of the island. Mount Austen—with a summit of —was not a single peak but a mixed ridgeline of rocky exposed and jungle-covered ridges and hilltops. After the defeat in the Battle for Henderson Field, the Army Section of Imperial General Headquarters directed Hyakutake to increase the numbers of troops and artillery emplaced on the ridgeline to help prepare for the next planned attack on the Americans. Hyakutake directed some of the units that were retreating from the Henderson Field battle area to fortify Mount Austen and nearby hilltops. The forces deployed to Mount Austen included the 124th Infantry Regiment under Colonel Akinosuka Oka and several artillery units. Later, surviving troops from the 230th Infantry Regiment—which had taken heavy losses during the Koli Point action and subsequent retreat—joined Oka's forces around Mount Austen.Frank, pp. 406–407, 411, 529; Miller, pp. 233–237; Jersey, pp. 344, 356, 360–362; Hough, pp. 363–364. The 8th Company, 230th Regiment took up positions near Mount Austen's summit. The 3rd Company, 10th Mountain Artillery under Captain Kyohtaroh Oishi with two 75mm Type 41 mountain guns was located on Hill 89. Nearby were several more Type 41 guns and crews from the 228th Infantry Howitzer Company. All were short of ammunition.
Reinforcement and resupply On 5, 7, and 8 November, Tokyo Express missions landed most of the 38th Division's 228th Infantry Regiment and the 1st Battalion, 229th Infantry Regiment on Guadalcanal. On 10 November, Japanese destroyers landed Lieutenant General Tadayoshi Sano—commander of the 38th Infantry Division—plus his staff and 600 more troops from the 38th. Hyakutake used the newly arrived troops to help stop an American attack west of the Matanikau from 8–11 November, then sent the 228th and 229th Regiment's units on 11 November to reinforce Oka's forces. Japanese Major General Takeo Itō—commander of the 38th Division's Infantry Group—later took command of the defenses around Mount Austen.Frank, pp. 421–425, 495; Miller, pp. 204, 228, 237; Jersey, pp. 303–304, 307, 361; Hough, pp. 363–364. At this time, Ito commanded about 1,000 troops of the 124th and 228th Infantry Regiments and supporting units on an inland line extending from Mount Austen to a point about west. Of this force, Maj. Takeyosho Inagaki with the 2d Battalion, 228th Infantry, occupied the northeast slopes of Mount Austen. Colonel Oka, with part of the 124th Infantry and other units, held the center of the line between Mount Austen and the Matanikau, while Col. Masaichi Suemura commanded the 1st and 3d Battalions of the 228th Infantry on the high ground west of the Matanikau. The 228th Regiment was commanded by Colonel Sadashichi Doi. Doi was later killed on an unknown date by American artillery fire. Suemura may have taken command of the 228th after Doi's death (Jersey, pp. 303, 344, 368). The 229th and 230th Regiment's units were apparently scattered at various places among the Japanese positions.
An attempt by the Japanese to deliver the rest of the 38th Division and its heavy equipment failed during the Naval Battle of Guadalcanal on 12–15 November. Only 2,000–3,000 of the remaining 7,000 troops from the division reached the island; most of their supplies, ammunition, and equipment were lost. Because of this failure, the Japanese canceled their next planned attempt to recapture Henderson Field.Frank, pp. 428–492.
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 from malnutrition, disease, and Allied ground or air attacks. The Japanese had delivered almost 30,000 soldiers to Guadalcanal since the campaign began, but by December only about 20,000 were still alive, with about 12,000 more or less fit for combat duty.Frank, pp. 493–527; Hough, pp. 364–365. On 12 December, the Japanese Navy proposed that Guadalcanal be abandoned. Despite opposition from Japanese Army leaders who still hoped that Guadalcanal could eventually be retaken, Imperial General Headquarters, with approval from Emperor Hirohito on 31 December, agreed to the evacuation of all Japanese forces from the island and establishment of a new line of defense for the Solomons on New Georgia. The Japanese titled the evacuation effort of their forces from Guadalcanal Operation Ke (ケ号作戦) and planned to execute the operation beginning on 14 January 1943.Dull, pp. 261, 268; Miller, pp. 336–338; Griffith, pp. 268–269.
In the meantime, the U.S. continued to deliver additional troops to Guadalcanal. The three infantry regiments of the U.S. Army's Americal Division, the 164th, the 182nd and the 132nd, were delivered to Guadalcanal on 13 October, 12 November, and 8 December, respectively. In addition, the U.S. Army's independent 147th Infantry Regiment plus the 2nd Marine Division's 8th Marine Regiment landed on 4 November. The reinforcements also included additional artillery, construction, aviation, naval, and support units.Frank, pp. 247–252, 293, 417–420, 430–431, 521; Griffith, p. 156; Miller, pp. 143, 173–177, 183, 189; Jersey, pp. 304–305, 345–346; Hough, p. 360. The Americal Division infantry regiments were national guard units. The 164th was from North Dakota, the 182nd from Massachusetts, and the 132nd from Illinois. The 147th had previously been part of the 37th Infantry Division.