of invading Australia was rejected in February 1942 and was not revisited, the Japanese attacks on Australia during the war were not precursors to invasion, as is sometimes claimed. The large air raid on Darwin on 19 February 1942 and the Attack on Broome on 3 March were conducted to prevent the Allies from using these towns as bases to contest the invasion of the Dutch East Indies and was not related to an invasion. According to Frei: The dozens of subsequent air raids on Northern Australia in 1942 and 1943 were mainly small and aimed to prevent the Allied air units based there from attacking Japanese positions. The Attack on Sydney Harbour in May 1942 had the goal of diverting Allied forces away from Midway Island prior to the Japanese attempt to capture it and the subsequent Japanese submarine campaigns off the Australian east coast in 1942 and 1943 were attempts to break the supply line between Australia and New Guinea during the New Guinea Campaign. Moreover, the Japanese attempt to capture Port Moresby in New Guinea by advancing along the Kokoda Track and landing at Milne Bay between July and September 1942 aimed to capture the town to complete Japan's defensive perimeter in the region. Once secured, Port Moresby was to have been used as a base from which Japanese aircraft could dominate the Torres Strait and Coral Sea, and not to support an invasion of Australia. A small Japanese reconnaissance unit carried out a brief landing on the Australian mainland during January 1944. Matsu Kikan ("Pine Tree"), a joint army-navy intelligence unit, landed to assess reports that the Allies had begun to build major new bases on the northernmost coast of the Kimberley region of Western Australia, facing the Timor Sea. After leaving their base at Kupang, West Timor, the unit – comprising 10 Japanese personnel in a commandeered fishing vessel crewed by West Timorese civilians – made brief visits to the uninhabited Ashmore Reef and Browse Island. On 19 January, Matsu Kikan entered York Sound on the mainland. While smoke was seen in hills to the east, the Japanese vessel was anchored and camouflaged with tree branches. Landing parties went ashore near the mouth of the Roe River. They reconnoitred the surrounding area for about two hours and filmed it with an 8 mm camera. The following day, Matsu Kikan personnel again reconnoitred the area, before