 During the campaign, Australian forces – supported by Australian and US aircraft – advanced through the Markham and Ramu Valleys during which there were minor clashes with Japanese forces, which withdrew towards their main defensive line in the Finisterre Range.The central geographical and strategic feature of the campaign was the imposing Shaggy Ridge, running north–south in the Finisterres; this was the scene of a climactic battle during which the Australians assaulted the Japanese positions in December 1943 and January 1944.Following the fighting around Shaggy Ridge, the Japanese withdrew towards the northern coast of New Guinea, where they were pursued by Australian and US forces advancing through the Finisterres and along the coast from Saidor.