The Allied air, ground and naval forces set out to cut the Japanese supply line, which was by barges moving along the coast between Madang and Fortification Point. Long Island was an important staging point for Japanese barges moving between Rabaul and Madang. In Allied hands, it could be a useful site for a radar station and observation post, and could provide radar coverage for the upcoming landing at Saidor. On 22 December 1943, the commander of Alamo Force, Lieutenant General Walter Krueger, issued his Field Order No. 8, directing the 2nd Engineer Special Brigade to seize Long Island. The operation was codenamed "Sanatogen", and was undertaken concurrently to landings around Cape Gloucester, on New Britain.