 On 22 September 1943, MacArthur's General Headquarters (GHQ) directed Lieutenant General Walter Krueger's Alamo Force to secure western New Britain and the surrounding islands. This operation had two goals, the first of which was to establish air and PT boat bases to attack the Japanese forces at Rabaul. The second objective was to secure the Vitiaz and Dampier Straits between New Guinea and New Britain so that convoys could safely pass through them en route to conduct further landings along New Guinea's north coast and beyond. To this end, GHQ directed that both Cape Gloucester and Gasmata on New Britain's south coast be captured. This offensive was code-named Operation Dexterity. The 1st Marine Division was selected for the Cape Gloucester operation, and the heavily reinforced 126th Regimental Combat Team from the 32nd Infantry Division was to attack Gasmata.
