Interviewer: That reminds me of something else. It may or may not be directly related but it pertains to being located on the forward slope. They obviously were not. As you said, they were either on the top or down at the base, and yet, when I entered the Army, we were being taught to defend on what was called the military crest of the hill, which is, in fact, the forward slope. Maybe that was a result of the Korean War.

Gen. DePuy: That was the Korean syndrome.

Interviewer: And, I think it still affects us today.

Gen. DePuy: And badly, particularly if you are putting infantry there; they can only get killed.

Interviewer: Right. I think you once mentioned that an incident like that happened in Europe.

Gen. DePuy: Yes. After the Bulge had collapsed and we started back to the east, we crossed a series of rivers. When we got up between the Prum and the Kyll Rivers, we encountered a very high open ridge. One of my company commanders put his “C” Company out in the snow on a bare forward slope. They dug in and everyplace they dug they made dark doughnuts in the snow. On the other side of the river there was another ridge. On top of that ridge were some German assault guns, and they waited until the company commander had all of his troopers scattered around in their foxholes on the forward slope, and then, they just started firing with their two assault guns. It was murder. Finally, after they killed and wounded maybe 20 men in that company, the rest of them just got up and bolted out of there and went over to the reverse slope, which is where they belonged in the first place. So, being on a forward slope when the enemy has direct fire weapons, high velocity direct fire weapons, is suicide. And, every time I went to Germany, I tried to convince Blanchard and the 1st Armored Division, the 3rd Armored Division, and the 3rd Division, at Hohenfels, of that. But, time after time, I’d find them all lined up in exposed, uncamouflaged, half-finished positions right within the sights of a Russian T-62 tank. It’s suicide unless they have frontal cover and are camouflaged. A trench is better. You see, a trench is a superior solution to that. And, a lot of people, the North Koreans, the South Koreans, the North Vietnamese, the Russians, and some Germans, use trenches. The Arabs, the Egyptians, the Syrians and the Israelis, sometimes use trenches. Why? Because you don’t know where they are when they’re in the trenches. When you are trying to shoot at people in a trench line, you have to ask yourself, “What part of a trench line do I shoot at?” You can waste a lot of ammunition trying to suppress a trench. But, trying to suppress clearly visible American foxholes or bunkers with high velocity weapons is a Cakewalk. It’s suicide to go into battle like that. But, our Army as a whole, doesn’t know that.

Interviewer: I’m afraid that we still are doing what people like myself were taught right after the Korean War. Apparently that’s how it was done on the hills of Korea. That’s how people dug in and fought.

Gen. DePuy: They were mostly dug in against mass Chinese infantry assaults. There weren’t any large direct fire weapons, or only a very few. They weren’t using tanks to snipe. So, you could say that that approach was partially justified, but, even then, they should have had frontal cover and have been totally invisible from the front. They should have been firing at angles, covered from the front, and totally camouflaged. If they had done all of that, then it would have been all right.

Interviewer: But, in fact, they were in bunkers, which I imagine were very obvious.

Gen. DePuy: Yes. They were little forts like the Special Forces forts in Vietnam. Or, like the positions I didn’t like in Europe. People always were trying to build a fort. But, they would only get it half done, and a half finished fort is an easy target for a tank gun. So, that’s not very good.

…

The DePuy foxhole was also called (for test purposes) PARFOX or parapet foxhole. The hole was either dug behind a large rock, mound or tree so that it afforded frontal protection. If no natural feature was available, the soldiers placed the spoil in front of the hole in the form of a berm high enough to cover the heads of the occupants from frontal observation or suppression. The soldiers fired at 45° angles from behind this camouflaged frontal cover. If time allowed, camouflaged overhead cover was added. Interlocking fields of fire covered all the killing zones and the position could not be suppressed by direct fire. One such position at Loc Ninh prepared by the 1st Battalion, 18th Infantry in 1967, caused an exchange ratio of enemy to friendly killed of 198 to 1.

(D’oh!)

It is perfectly normal for a soldier at risk to look in the direction of his personal menace. That means that the infantry soldier hiding in a hole in the ground has to lean forward in his foxhole and raise his head to get a glimpse of the enemy threatening to overrun him. Then he aims his weapon at the enemy. Wrong, said DePuy. And what he taught, indeed insisted upon, was absolutely counterintuitive.

A foxhole would, in the first place, be hidden in the natural terrain so that it could not be seen from the front. Second, a parapet of earth and rocks would be built at the front of the hole, and the dirt used for this purpose would be camouflaged. The soldiers, usually two per hole, would focus their attention and shooting in a 45-degree angle — one to the left front, the other to the right front — protected by the mound of camouflaged dirt, or a small hill, or a rock, to the front. This is, of course, unnatural. The natural reaction of someone threatened from the front is to look and to shoot in that direction. However, the DePuy technique meant that the men in the hole would fire across the front of their neighbor’s foxholes, left and right. Their neighbors would fire in the same manner, so that the fires were mutually supporting, and no one would be exposed to the front.

That was the basic (and unnatural) idea. It was enhanced by staggering the holes in some depth, the way the Germans had, not in a straight line, which would be easier for the enemy to locate. Overhead cover would be added if the unit remained for more than a few hours. Bunkers followed the same principle: orient outgoing fires at a 45-degree angle to the front. That way, no apertures or firing ports were presented to the direct front.

Soldiers conditioned to sandbag castles with firing ports to the front — the way it was routinely done by the U.S. Army in Korea — would find a DePuy battalion in a defensive position unusual, even anathema.

He recalls asking his father about research projects that were historical and analytical, Billy’s strengths. His father was “a serious student of history,” according to Bill Jr., and was “terrific” at teaching it…. Similarly, as he studied the fortifications of Vauban, the great French military engineer, which featured star-shaped forts providing enfilade fires and mutual support, the elder DePuy told his son of the German and French fortifications he had seen in World War II, and he explained how those observations led to the DePuy foxhole.

p. 201, General William E. DePuy: Preparing the Army for Modern War, by Henry Gole

Of all places, I spotted The Defence of Duffer’s Drift in the “see also” section of the Wikipedia article for the recent Tom Cruise sci-fi film Edge of Tomorrow. The link in narrative structure is amusing to contemplate.