Battle of Mount Austen, The Galloping Horse, and The Sea Horse - Aftermath

Aftermath

On 15 January, an IJA representative from Rabaul reached Guadalcanal on a Tokyo Express mission and informed Hyakutake of the decision to withdraw Japanese forces from the island. Grudgingly accepting the order, the 17th Army staff communicated the Ke evacuation plan to their forces on 18 January. The plan directed the 38th Division to disengage and withdraw towards Cape Esperance on the western end of Guadalcanal beginning on 20 January. The 38th's retirement would be covered by the 2nd Division and other units, which would then follow the 38th westward. Any troops unable to move were encouraged to kill themselves to "uphold the honor of the Imperial Army". From Cape Esperance the Japanese navy planned to evacuate the army forces over the last few days of January and first week of February with a projected completion date of the evacuation of 10 February.

The U.S. and its Allies mistook Japanese preparations for Ke as another reinforcement attempt. With this in mind, Patch ordered his forces to launch another offensive against the Japanese forces west of the Matanikau. On 21 January, the 27th and 161st Regiments pushed westward from the area of the Galloping Horse. The Americans—unaware that the 38th Division was withdrawing in preparation to evacuate the island—were surprised to encounter light resistance. Advancing more quickly through the inland hills and ridges than the Japanese had anticipated, by 22 January the Americans were in position to capture Kokumbona on the coast, headquarters of the 17th Army, and completely cut off the remainder of the 2nd Division.

Reacting quickly to the situation, the Japanese hurriedly evacuated Kokumbona and ordered the 2nd Division to retire westward immediately. The Americans captured Kokumbona on 23 January. Although some Japanese units were trapped between the American forces and destroyed, most of the 2nd Division's survivors escaped.

Over the next week, the Japanese rear-guard—assisted by difficult terrain—effectively delayed the American advance westward from Kokumbona. General Patch—still believing that a Japanese reinforcement effort was imminent—kept most of his forces back to guard Henderson Field, sending only one regiment at time to continue the advance. Thus, the majority of the surviving Japanese army forces were able to gather at Cape Esperance by the end of January. On 1, 4, and 7 February, Japanese warships successfully evacuated 10,652 army troops from the island. On 9 February, the Americans discovered that the Japanese were gone and declared Guadalcanal secure.

In hindsight, some historians have faulted the Americans—especially Patch and Admiral William Halsey, commander of Allied forces in the South Pacific—for not taking advantage of their ground, aerial, and naval superiority to prevent the successful Japanese evacuation of most of their surviving forces from Guadalcanal. Patch and Harmon's insistence on taking Mount Austen has been cited as one of the factors that delayed the American's main attack to the west, giving the 17th Army a chance to escape. Said Merrill B. Twining of the Japanese forces deployed on and around Mount Austen, "Theoretically these Japanese did offer a threat to our major force advancing westward along the coast, but as a practical matter these isolated groups were composed of sick and starving men unable to do anything more than die in place. Under the circumstances disclosed by subsequent events, it is obvious that Mt. Austen was just part of the scenery and of no significant import to either of the antagonists."

Nevertheless, the successful campaign to recapture Guadalcanal from the Japanese was an important strategic victory for the U.S. and its allies. Building on their success at Guadalcanal and elsewhere, the Allies continued their campaign against Japan, ultimately culminating in Japan's defeat and the end of World War II.