The Battle of Buna-Gona between November 1942 and January 1943, saw Australian and United States forces attack the main Japanese beachheads in New Guinea, at Buna, Sanananda and Gona. Facing tropical disease, difficult terrain and well constructed Japanese defences, the allies only secured victory with heavy casualties. The battle set the tone for the remainder of the New Guinea Campaign. The offensives in Papua and New Guinea of 1943–44 were the single largest series of connected operations ever mounted by the Australian armed forces. The Supreme Commander of operations was the United States General Douglas Macarthur, with Australian General Thomas Blamey taking a direct role in planning and operations being essentially directed by staff at New Guinea Force headquarters in Port Moresby. Bitter fighting continued in New Guinea between the largely Australian force and the Japanese 18th Army based in New Guinea until the Japanese surrender in 1945.