The Japanese Retreat From Ioribaiwa

By the third week of September 1942, General Tomitarō Horii's Japanese troops had pushed south across the Owen Stanley Range in New Guinea, forcing the Australians back day by day. The Australians abandoned their position near Efogi and fell back along the Kokoda Trail to Imita Ridge, with the fighting now only thirty miles from Port Moresby.

Then the advance stopped. At Ioribaiwa the Japanese were halted, and the Allies scraped together local air superiority over the position, enough to break the momentum. American reinforcements reached Port Moresby to join the Australians, and for the first time in weeks the defenders could plan an offensive of their own rather than another retreat.

The Milne Bay garrison, at the eastern tip of New Guinea, had already forced a separate Japanese landing force to evacuate earlier in the month, closing off another approach to Port Moresby. Horii's men on the Kokoda Trail were now the only Japanese ground threat to the town, and they were running low on everything but resolve.

By September 25, Horii's forces were pulling back from Ioribaiwa, ground they had just spent weeks taking. The order came down from Tokyo, layered on top of a problem his men had lived with since they left the coast: every round of ammunition and every ration for the drive on Port Moresby had come up a single track over the mountains, carried by hand, and the supply line could not keep pace with the advance. Imperial General Headquarters had also decided that the Americans who had gone ashore on Guadalcanal on August 7 needed the men and shipping more urgently than the push on Port Moresby did.

Horii's withdrawal sent his troops back over the same ridges and villages they had fought through days earlier, this time heading for Buna and Gona on the north coast. What had been the closest Japanese approach to Port Moresby by land became, within days, the start of an Australian pursuit back down the Kokoda Trail. The fighting in New Guinea did not end. It shifted toward the coast, where Buna and Gona would become the objectives of a longer, costlier campaign before the year was out.

For the Australians who had spent weeks giving ground across the Owen Stanleys, September 25 was the day the campaign changed direction, even if nobody on Imita Ridge yet knew it.