We’re still working our way (oh so slowly) through the Greenbooks. We’re currently about halfway through the history of the Army campaign at Okinawa (we’re NOT reading them in order).
One of the things that is most striking is just how little frontage there was for such huge numbers of troops involved. At the Shuri line defenses, the island is only about 5 miles wide, and yet three entire infantry divisions were line abreast. The divisions (and in turn each of their subordinate formations) tended to follow the “two up, one back” rule of thumb. That is, each division would have two regiments abreast, with one in reserve to exploit any successes, or refitting and receiving replacements. Likewise, the regiments, battalions, and companies would have two units forward, with one in reserve. Still, that’s a very narrow frontage for an entire army corps.
The Shuri line of defenses were so formidable, however, that the entire corps advance was dependent on platoon and company attacks on strongpoints on the line. If one strongpoint couldn’t be reduced, the units attempting to bypass it would be pinned by automatic weapons, mortars and artillery the Japanese had positioned on the reverse slopes. Time and again, US troops would pay a horrific price to seize the front slope of a ridge, only to be too depleted to advance upon the rear slope. For that matter, the reverse slope defenses of the Japanese were masterpieces of the military art. They would contest control of the crest of a ridge, showering mortars and grenades on US troops clinging to the front slope. They had caves, bunkers, pillboxes and spiderholes, all linked by extensive tunnels, that made attacking downhill on the reverse slope every bit as hazardous as seizing the front slope. Their positions were virtually impervious to mortar, artillery, and even 16” naval gunfire. To make matters worse, when US forces managed to get enough troops and firepower onto a ridge to contest the reverse slope, enemy position on the frontal slope of the next ridge would fire upon them.
NISHIBARU ESCARPMENT AREA, which the 96th Division took. On 21 April the 3d Battalion, 382d attacked eastern end of escarpment by moving through the 381st’s zone to the ridge, then turning east. (Original caption from The US Army in World War II)
That’s an entire division’s objective. And it would take over a week to capture.
The interlocking nature of the Japanese positions was such that the preferred tactic of flanking attacks was impossible. Any move to the flank of one position was just a move to the front of another. Consequently, US forces had to time and again make costly frontal attacks on the most carefully constructed infantry defensive positions seen in the entire war. Time and again, platoons would attack to destroy a single strongpoint. Units that would normally have a strength of almost 50 men would finish the morning with a bare handful of effectives. But what option was there? A platoon’s objective for the day might be a single enemy position only 20 meters across, and only 50 meters away. Entire regiments would be gutted of infantry strength in just a few days of attack.
The Japanese knew they had no chance of defeating the US on the island. But then, that wasn’t their mission. Their role was to buy time, to bleed the US as much as possible and give the forces in the Home Islands more time to prepare for the inevitable invasion. And not only were the Army forces (and Marines) ashore being whittled down. The Navy, tied to Okinawa waters to support the men ashore, was being bled white by the Kamikaze attacks day and night. Those losses meant the 10th Army ashore had to keep attacking, to wrap up the campaign as quickly as possible.
Fast forward 40 years, and my experiences as a light infantryman. I was used to light infantry operating over vastly larger frontages. A rifle company on a seek and destroy mission might cover a zone a mile wide and three miles deep over a 24 hour mission. And as a mechanized soldier, the space a single company might be expected to operate over was vastly increased.
But could today’s forces do any better against a defense such as 10th Army faced in Okinawa? I doubt it. In fact, in some ways, we’d be worse off. While we have more automatic weapons at the platoon level, the organic firepower of a platoon isn’t much more than it was then. And supporting arms aren’t that much greater up to the battalion level. And weapons that were key to destroying the Japanese then are nowhere to be found today. One of the most useful weapons was the flame-throwing tank. Modified M4 Shermans replaced the 75mm gun tube with a flamethrower with a range of roughly 150 yards. Today, flame weapons are almost unheard of on the battlefield.
The Army would desperately like to avoid the awful “hugger-mugger” type fight that exemplified the Okinawa battlefield. But sometimes, that’s not always an option. Operations in Fallujah showed that the enemy gets his vote on where the battle will take place. And fighting in cities takes an enormous commitment in manpower. A single small building takes at least one squad, and often an entire platoon to secure. Our advantages in weapons and technology are nullified. Only our advantage in training remains. But training will only go so far. Two men in a room, one with an M16, one with an AK- that’s far to close to a fair fight for my tastes. And yet, the Army will have to face this situation again on battlefields of the future. Sometimes, it just comes down to guts.