The Army’s official summary, United States Army in World War II, The War in the Pacific, Campaign in the Marianas (published 15 years after the operations) attributed some errors to Holland Smith’s handling of a real problem, and it also gave full recognition to the difficult terrain and bitter resistance that the Army regiments faced. The history stated that:
... there is no doubt that the 106th Infantry Regiment of the 27th Division was late in jumping off in the attack on the morning of 23 June—even though not so late as Holland Smith charged. On the 23d and again on the 24th, the Army troops attacking Death Valley were slow and faltering in their advance. According to the testimony of General Jarman, who took over the division from Ralph Smith, the unit leaders of the 106th Infantry were hesitant and apparently confused. Although the Army troops in Death Valley sustained fairly heavy casualties, the two Marine divisions on the flanks suffered greater ones. Yet the Marines made considerable advances while the 165th Infantry registered only small gains—the 106th Infantry almost none at all.
No matter what the extenuating circumstances were—and there were several—the conclusion seems inescapable that Holland Smith had good reason to be disappointed with the performance of the 27th Infantry Division on the two days in question....
Back where the conflict was with the Japanese, the 4th Marine Division had overrun most of the Kagman Peninsula by the night of D+10. The shoreline cliffs provoked sobering thoughts in a young officer in the 24th Marines:
We were close to the northern shoreline of the peninsula. And right there the Japs had dug a big emplacement. They hadn’t had time to finish it, but we could see that it was situated so as to fire right down the beach-line. Any troops landing on that beach would have received a terrible enfilading fire from this gun position. Not far from the emplacement were the guns that had been destined to go into it: huge, 5-inch, dual-purpose naval guns. They were deadly things, and I was glad the enemy had never gotten them into action. Now they lay there on their wooden skids, thickly coated with grease, wrapped in burlap—impotent.
This unfinished state of the Japanese defenses was, in fact, a critical factor in the final American victory on Saipan. The blockading success of far-ranging submarines of the U.S. Navy had drastically reduced the supplies of cement and other construction materials destined for elaborate Saipan defenses, as well as the number of troop ships carrying Japanese reinforcements to the island. Then the quick success of the Marshalls campaign had speeded up the Marianas thrust by three months. This was decisive, for “one prisoner of war later said that, had the American assault come three months later, the island would have been impregnable.”
When a Japanese survivor did emerge from a cave, Marines were always on the alert for treachery. This enemy soldier had a stick of dynamite in his hands, but was shot before he could throw it.
Department of Defense Photo (USMC) 87137
The 4th Marine Division encountered more than cane fields in the Kagman Peninsula—the cliffs near the ocean were studded with caves. A 20-year-old private first class in Company E, 2d Battalion, 23d Marines, Robert F. Graf, described the Marine system for dealing with these and the others that were found all through the bitter campaign:
The firepower was intense, and we were working our way up to where the shots originated. Quite often there would be multi cave openings, each protecting another. Laying down heavy cover fire, our specialist would advance to near the mouth of the cave. A satchel charge would then be heaved into the mouth of the cave, followed by a loud blast as the dynamite exploded. Other times it might be grenades thrown inside the cave, both fragment type which exploded sending bits of metal all throughout the cave, and other times [white] phosphorous grenades that burned the enemy.
Also the flame thrower was used, sending a sheet of flame into the cave, burning anyone that was in its path. Screams could be heard and on occasions the enemy would emerge from the caves, near the entrance, we would call upon the tanks, and these monsters would get in real close and pump shells into the opening.