Before the war a landing ground had been established on the relatively flat ground that lay at the apex of the peninsula. Following the Japanese invasion of New Britain in early 1942, the landing ground had been developed into two airstrips (the larger of the two being long). The area was assessed by Allied intelligence as largely being unsuitable for large-scale development, with reefs to the south, west and north hampering the movement of large vessels, and a lack of protected anchorages suitable for such vessels. The few areas suitable for such vessels were open to the sea and were not considered perennial, being affected by the changing seasons. Nevertheless, small craft could operate along the coast, and Borgen Bay had been developed into a staging area for barge operations between mainland New Guinea and the main Japanese base around Rabaul on the eastern end of New Britain.