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.
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.
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.
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.
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.
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 6 mi (9.7 km) 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 1,514 ft (461 m)—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.
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.
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.
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. 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.
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.
On 9 December, U.S. Army Major General Alexander Patch—commanding general of the Americal Division—succeeded Vandegrift as commander of Allied forces on Guadalcanal and Tulagi. That same day, the 5th Marine Regiment departed the island, followed by the rest of the 1st Marine Division by the end of the month. Patch was ordered to eliminate all Japanese forces remaining on Guadalcanal. Patch told his superior—Millard Harmon, who commanded all U.S. Army forces in the South Pacific—that he needed more troops to accomplish his mission. In response, Harmon ordered the 25th Infantry Division, which was in the process of relocating from Hawaii to the South Pacific Area, to ship directly to Guadalcanal. The 25th's units would arrive at Guadalcanal in stages during the last two weeks of December and the first week of January 1943. In addition, the rest of the 2nd Marine Division's units—including the 6th Marine Regiment—were ordered to Guadalcanal during the same time period. By 7 January, American forces on Guadalcanal would total just over 50,000 men.
Battles
First Battle of Mount Austen
On 12 December 1942, a small group of Japanese soldiers from the 38th Field Engineer Regiment successfully infiltrated the American lines from the south, destroying a fighter aircraft and a fuel truck on Henderson Field before escaping back to friendly lines. Two days later, a U.S. Army patrol from the 132nd Infantry Regiment skirmished with a group of Japanese on the eastern slopes of Mount Austen. On 15 December, in yet another night infiltration raid onto Henderson Field, a Lieutenant Ono led four men equipped with picric acid blocks past American sentry positions, destroying several P-39 Airacobra fighters. Throughout the Guadalcanal campaign, Japanese forces would continue night infiltration tactics against U.S. forces, causing few American casualties.
General Patch, however, was convinced that these events illustrated an unacceptable risk to Henderson Field by Japanese troops stationed on and around nearby Mount Austen. Thus, on 16 December, in preparation for a planned general offensive to try to destroy all Japanese forces remaining on Guadalcanal, Patch elected to first secure the Mount Austen area. He therefore ordered the 132nd Infantry Regiment to immediately seize the objective. While the 132nd Infantry Regiment had little modern combat experience aside from jungle skirmishes and patrols, it was proud of its combat history, having participated in both the Civil War and World War I, and its young reserve officers and non-commissioned officers considered themselves skilled in rifle and machine-gun tactics and marksmanship.
The 132nd's commander—Colonel Leroy E. Nelson—directed his 3rd Battalion to lead the American assault on the first of several hills, followed by the regiment's 1st Battalion. Artillery support was provided by 105 mm howitzers from the U.S. Army's 246th Field Artillery Battalion and the 75 mm pack howitzers of the 2nd Battalion, 10th Marines.
The exposed hills making up the Mount Austen complex were arbitrarily numbered by the Americans for reference purposes (see map at right). On 17 December, Nelson's 3rd Battalion—commanded by Lieutenant Colonel William C. Wright—advanced south of Hill 35 and began to climb toward Mount Austen's summit near Hills 20 and 21. In order to achieve its timetable set by the division commander, the battalion was forced to leave behind many of its support weapons, such as heavy mortars and machine guns, and to take only limited quantities of ammunition and supplies, all of which had to be hand-carried along hacked-out paths through thick jungle. At 09:30 on 18 December, as Wright's lead elements approached, Japanese defenders pinned down the Americans with machine-gun and rifle fire. Exhausted and dehydrated by their trek through the thick jungle, Wright's troops—unable to deploy quickly out of column formation—made no headway against the Japanese defenses.