piles and rocks. Over all this were piled earth and sand mixed with short logs, coconuts, and the like. When the bunker, 7 to 8 feet high, was camouflaged with fast-growing jungle vegetation, it became almost impossible to spot in the tangled underbrush. The campaign was to prove that as a shelter it would withstand almost anything but a direct hit by a heavy artillery shell with delayed-action fuze. Entrances to the bunkers usually were in the rear, covered by fire from adjacent bunkers, and often angled so that a hand grenade tossed in the door would not kill the occupants.
Some of the bunkers had fire slits for machine guns or rifles. In this case snipers in the trees overhead served as observers. The snipers would fire warning shots when our troops approached, and then a machine-gun burst would come from the bunker. The bunkers, however, were principally used for shelter during aerial bombardment and shelling. After such attacks the Japanese crawled out along the communication trenches and took up firing positions in individual emplacements to the sides and front of the bunkers. Not all of these shelters were occupied at any one time; the garrison shifted from point to point to meet our attack, and our troops soon learned that each captured bunker must be garrisoned or destroyed to prevent the enemy from infiltrating and reoccupying it. The Japanese worked steadily to improve and strengthen their system of defenses and constructed new lines as they were forced back.
Japanese tactics during the Buna campaign were strictly defensive. Counterattacks were few and came mostly at the end of the operation, when the enemy's situation was growing desperate. For the most part he dug himself in and waited for our troops to cross his final protective lines. Time and time again our troops were baffled by the enfilading fire from positions they could not see. As the soldiers kept complaining, "If we could only see them, it wouldn't take long." But the Japanese light machine guns and Arisaka rifles gave off no flash, and in the great tent of towering trees sound so reverberated that the report of a weapon did not aid in its location. Our troops had to locate each bunker by costly fumbling, then either outflank it by creeping through a swamp or charge it again and again until the defenders were worn out. The Japanese never surrendered. As one soldier explained, "They are tough babies all right, but I guess part of the toughness comes from them not being able to go any place else; they just stay there and die."
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