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, but 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 NCOs considered themselves skilled in rifle and machinegun 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,