As General Horii's bedraggled columns closed in on their objective, the Japanese planners at Rabaul decided to launch a new campaign in Papua despite the continuing demands of their Guadalcanal operations. Their reason was that if the proposed operation succeeded, it would give them key airfields less than two hundred miles from Port Moresby. These were being constructed by the Allies at Milne Bay who had belatedly understood the importance of controlling the areas adjacent to the bay that prior to the war had been only sparsely settled.
The Japanese were almost completely ignorant of the terrain and climatic conditions. Even the Australians who administered the area did not fully comprehend the difficulty of carrying on military operations there. The bay itself was a deep cleft in the lizard's tail of extreme southeast Papua; it extended approximately twenty miles inland and was between four and five miles wide. On either side were mountains rising as high as 4,000 feet and dropping almost to the shoreline, leaving only a narrow strip of land between them and the sea. Much of this was covered by jungle. Because the region received more than two hundred inches of rain annually, the many streams overflowed, creating coastal swamps. At the head of the bay was a wide alluvial plain on which Lever Brothers had planted a large coconut plantation. The company headquarters and service buildings were located at Gili Gili. The dock there consisted of two large barges placed side by side with a ramp leading to a small jetty. The plantation area was serviced by only a few roads, most of them