In early July 1942, the 39th Infantry Battalion of the Australian militia was sent to reinforce local Papuan infantry at Kokoda Pass in the Owen Stanley Mountains. The area was a critical terrain feature the Japanese would have to secure in order to assault Port Moresby from the north. Denied an invasion of Port Moresby by sea as a consequence of the Battle of the Coral Sea, the Japanese now endeavored to take it by land, working southwest along the treacherous Kokoda Trail that crossed the east-west Owen Stanley Mountains. The trail was as high as 8,000 feet in places and as low as 1,000 feet, with valleys that sloped 60 degrees. On 21 July, the Japanese Yokohama Force of engineer, infantry, and marine units landed at Buna on the north side of New Guinea to prepare the way for the follow-on South Sea Detachment commanded by Major General Horii Tomitaro, who arrived himself in mid-August. Horii now pushed a force inland from Gona, drove back local Allied troops, and moved up the rugged and treacherous track of the Kokoda Trail that ran south to Port Morseby. By mid-August, the Japanese had seized the passes over the Owen Stanley Mountains that ran across the island.
During the march, Japanese forces quickly fixed and bypassed the detachments of Australian and Papuan forces guarding several key areas, including Kokoda. The 21st Brigade of the Australian 7th Division was then sent to relieve the elements that had borne the brunt of the fighting. The Japanese, however, outflanked the 21st Brigade and forced it to withdraw, a maneuver repeated several times over the next few weeks. In early September, the 25th Brigade arrived to reinforce the 21st, and in mid-September, it joined in the unsuccessful defense at Ioribaiwa, some 30 miles from Port Moresby. The Japanese entered that village on 16 September in what was their last land victory of the Pacific war. There, Australian and U.S. forces under Major General Edmond F. Hering, benefiting from Allied air superiority, helped contain the Japanese advance.
On 25 August, the Japanese landed 1,900 men at Milne Bay at the eastern tip of Papua. This force planned to make its way west and support Horii's drive on Port Moresby. Australian forces, not greatly superior to the Japanese in size but with the advantage of air support, contained the landing and then mounted a counterattack. On the nights of 5 and 6 September, the Japanese evacuated 1,300 survivors, half of them wounded. The Australian victory in the Battle of Milne Bay was extremely important: both a humiliation for the Japanese and a lift for the Allies, it proved the Allies could defeat the Japanese in jungle warfare. And its outcome isolated the Japanese coming off the Kokoda Trail.
The Japanese engineers at Buna had hoped to construct a small road along the Kokoda Trail. When this proved impossible, the engineers fortified an area about 10 miles long and several miles deep between Gona and Buna on the Solomon Sea. There, 7,000 Japanese, half of them survivors of the Kokoda Trail march, awaited an Allied attack.
Fighting on Guadalcanal deprived the Japanese of resources for Papua, and during October, Allied pressure and orders from General Imamura Hitoshi on Rabaul to withdraw caused Horii to fall back over the Owen Stanley Mountains. The Australian 7th Division followed. But instead of withdrawing to the coast at Buna, Horii decided to make a stand near the Kokoda Trail between the settlements of Oivi and Gorari, a few miles east of Kokoda. He was confident of victory, but by early November, the Allies had learned much about jungle warfare, and in the Battle of Oivi-Gorari, the Australians flanked the Japanese position, driving Horii's men off the trail and into a river. Taking advantage of the dense jungle, many Japanese managed to reach the coast. Horii was not among them; he drowned a week later while crossing the Kumusi River.
In late November 1942, the Australians approached Buna from the Kokoda Trail. Meanwhile, the U.S. 32nd Division advanced up the Papuan coast in a strange collection of fishing boats and coastal vessels. Because the coast was poorly charted and also because there were numerous reefs as well as concerns over Japanese aircraft, the U.S. Navy did not support the operation with transports or warships, which adversely affected its progress. The Kokoda Trail was far too rugged to move artillery and significant quantities of supplies by that route; nor could artillery be brought in on the small U.S. Army vessels. Thus, the 32nd Division, unprepared for the jungle conditions in any case, had to go into battle without artillery support against Japanese machine-gun nests that were well dug in and concealed in the dense jungle.
The Australian-U.S. advance against the Buna-Gona fortified zone began on 18 November. Progress in the jungle and swamps was slow, and many of the troops were incapacitated by disease. Fortunately for the Allies, fighting on Guadalcanal meant that the Japanese on Papua received few supplies. The Japanese had to deal not only with disease but also with malnutrition.
Displeased with the situation, MacArthur brought in U.S. Army Lieutenant General Robert L. Eichelberger to command I Corps, ordering him to take Buna or not come back alive. Eichelberger flew to Dobodura on 1 December 1942 to take command of the American sector. An effective commander, he soon restored Allied morale. In early December, U.S. engineers were able to open an airfield near Buna, significantly improving the Allied supply situation. On 9 December, the Australians took Gona. The more heavily fortified Buna resisted U.S. pressure, but on 23 January 1943, a concerted attack by Australian and U.S. forces secured it as well.
J. G. D. Babb and Spencer C. Tucker
Bergerud, Eric. Touched with Fire: The Land War in the South Pacific. New York: Viking, 1996.; Harries, Meirion, and Susie Harries. Soldiers of the Sun: The Rise and Fall of the Imperial Japanese Army. New York: Random House, 1991.; Mayo, Lida. Bloody Buna. New York: Doubleday, 1974.