The Allied invasion of Aitape, New Guinea, on 22 April 1944 was one of three simultaneous invasions far to the rear of what conventional military wisdom considered the front line of Japanese resistance. It recently has been revealed that the U.S. ability to read the Imperial Japanese Army's (IJA) most secret codes, the information from which was disseminated as the so-called Ultra intelligence, contributed significantly to these bold operations. Armed with special intelligence, General Douglas MacArthur, commander in chief, Southwest Pacific Area (SWPA), conducted a series of amphibious flanking maneuvers that forced the Japanese to fight at places of MacArthur's choosing. Aitape was one of those places.

In the lexicon of historians of World War II, "forgotten" has become a popular modifier. One reads of the forgotten front, forgotten soldiers, the forgotten army, and so on. The operations in New Guinea also qualify for the forgotten label. As James Jones wrote about those campaigns, "A year it had taken from Guadalcanal to Sansapor. And how many invasions? Fifteen? Almost all of them names people in the United States never heard of, and still haven't." [1] The landings at Aitape and the subsequent Driniumor River campaign were two such names.

If military readers related the historical lessons of the Driniumor River fighting to today's doctrine, they would discover striking similarities. Although today's FM 90-5 has incorporated many lessons from the past, it is intended to serve as a how-to-fight manual for the individual soldier. Guidance for the intricacies of larger unit operations--battalion and above--is lacking. Current U.S. Army jungle warfare doctrine, for instance, uses the same terminology as its 1941 predecessor to describe the general conduct of operations in jungle terrain through the use of covering force, main battle, and rear areas.

It does not, however, spell out the exact role of a covering force or how to establish the respective battle areas in such a situation.

Instead, the interested reader is referred to FM 100-5, which describes the covering force in terms of a European style battlefield. In 1929, B. H. Liddell-Hart wrote, "The practical value of history is to throw the film of the past through the material projector of the present onto the screen of the future." He naturally assumed that the audience paid attention to the film. If the "film of the past" is forgotten, so too are the U.S. Army's tactical and doctrinal legacies from World War II.

As John F. Morrison Professor of Military History at the U.S. Army Command and General Staff College, D. Clayton James, MacArthur's foremost biographer, often expressed his puzzlement about the U.S. Army's historical neglect of its extensive campaigns in the Pacific theater. An exclusive focus on northwest Europe, he suggested, misrepresented not only the global role of the U.S. Army and its adaptability to the diverse conditions of World War II but also the very nature of that war. If we did not understand the Pacific War, we could not comprehend the nature of global conflict. Professor James spoke of the highest strategic levels, but he also suggested to the Combat Studies Institute that the battles along the Driniumor River would be a suitable topic for tactical analysis as a Leavenworth Paper. The immediate question was how to translate his strategic perspective into a tactical framework. In one sense, the paradox of New Guinea as a theater of war solved the problem.

New Guinea was so large that it absorbed vast numbers of troops, more than nine U.S. infantry divisions by July 1944, but the jungle terrain fragmented the deployment of large formations attempting to operate en masse. At the tactical level, company- and platoon-size actions were the norm. The actual number of U.S. combat troops was small, their combat service support large. [1]

The Japanese situation was the reverse, mainly because MacArthur's leapfrogging strategy had isolated the Japanese from their logistic support. From MacArthur's strategic viewpoint, Aitape was hailed as a classic victory, but to the few men who actually fought the battle, it was a swirling, confused melee.

Chronologically, the Aitape campaign fell into distinct phases, the strategic-operational and the tactical. The strategic and operational phases began in January 1944 when Southwest Pacific Area commander and staff first conceived the leap to Hollandia-Aitape. It culminated in early July when 6th Army completed the operational deployment of Persecution Task Force, the code name for the American forces at Aitape. Although occasional skirmishes punctuated this period, the full tactical fury of protracted battle did not commence until the night of 10-11 July 1944, when the entire Japanese 18th Army attacked Persecution Task Force defenders along the Driniumor River. By extending this dichotomy, the first phase was preparatory as both sides deployed for combat. At this time, Ultra intelligence revelations about Japanese capabilities and attack plans were instrumental in American operational deployment.

The planning and maneuvering that brought Japanese and American forces to the Driniumor River serve as the focus for the first part of this study. As the battle raged, however, the respective commanders had to depend on the collective skills of their individual soldiers and hope that their operational deployments, training, and tactical doctrine would bring them victory. The tactical struggle, or second phase, then, was as removed from the strategic and operational phase as the experience of the officers and men on the front line was from the abstract map symbols that represented their units at higher headquarters.

The purpose of this Leavenworth Paper is to integrate American and Japanese strategic, operational, tactical, and human dimensions into a narrative form. The focus is on the 112th Cavalry Regiment because that unit played a significant role in defeating a numerically superior Japanese force that tried to outflank an American covering force. Official histories in both English and Japanese languages illuminate the decision-making processes of the combatants at the strategic and operational levels that resulted in the deployment of men and their war-making equipment to the Driniumor. Ultra adds the intelligence dimension to American decision making.

At the tactical level, however, events are less clear. For the purposes of organization, three major engagements occurred along the Driniumor River in July and August 1944.

On the night of 10-11 July 1944, Japanese troops of the 18th Army broke through and overran American covering force defenders on the Driniumor. An American counterattack characterized by bitter fighting eventually sealed this penetration. The third major battle-more correctly a series of company and platoon level engagements lasting three weeks-raged around the south flank of the American positions as the Japanese tried to turn the U.S. line. This more specific level is difficult to reconstruct with exactitude because of the confused nature of jungle fighting when men only a few yards distant were out of sight and earshot. Small parties of Japanese and Americans fought and died in anonymity. Nevertheless, reference to contemporary military reports and war diaries makes it possible to impose a degree of order, necessarily arbitrary, on the operations and then to describe the fighting.

The motivations of the troops who fought in such a hideous environment are central to an understanding of the battle from the small unit perspective. I relied on the personal accounts of American and Japanese veterans for an understanding of these complex and highly significant questions. Oral history, if obtainable, becomes invaluable because it personalizes the official accounts and fills in the gaps in the historical record.

The U.S. Army's 32d Infantry Division and 112th Cavalry Regiment fought for forty-five days along the Driniumor. Those who survived the hardship, terror, or rare exhilaration of the firing line can provide an insight into the emotions and impressions of their struggle. It was a savage battle in primitive conditions where no quarter was asked or given.