Madang was captured by the Japanese in early March 1942, along with Lae and Salamaua as part of operations to establish a key base at Rabaul. After this, the Japanese had worked to improve various means of communication around the area including roads, port facilities and airfields to utilise Madang's deep-water harbour as part of a forward base, which was established around Madang and Alexishafen, north, to support forces in the Salamaua–Lae area. In 1943–1944, Australian and US forces began offensive actions in New Guinea, having stemmed the tide of the Japanese advance during the fighting in 1942. In September 1943, the Allies had secured Lae and Nadzab. Shortly afterwards, the 9th Division had landed on the Huon Peninsula and had subsequently secured Finschhafen and began clearing inland. By October 1943, the next objective for the Australians was Shaggy Ridge, a series of high positions on the inland route from Dumpu to Madang, which was held by Japanese infantry, supported by artillery and engineers.