Choosing reverse or forward slope defense

[SteveP]

I've been puzzling over this question recently: what are the basic principles or conditions which should lead one to choose a forward slope or reverse slope defensive setup? I assume that all armies have standard doctrines for this; I just don't happen to know what they are. Plus there are the "what works best in CM" considerations, if any.

A few parameters: I am using the terms forward and reverse slope in the broadest way. Not just ridge lines, but also buildings along a street, a line of forest, etc. I'm also not interested in personal preferences here. It's more on the subject of doctrines and theory. I recognize that sometimes the choice is "obvious" (though people may have very different opinions about that). Also, I think there may be situations in which the correct answer is to have units in both places (but then which go where?). I am thinking of situations in which there is decent cover on both slopes, so that isn't a determining factor, and where the defense has a mix of long range and short range weapons, with neither predominating.

If that isn't an adequate statement of the problem, I'd be happy to expand on it.

[Mike Summers]

This topic has been discussed quite a bit on the boards. I would think that if you performed a quick search for it, particularly through JasonC's posts, and you will find a very thorough treatment of the subject.

[JasonC]

The purpose of a reverse slope defense is to shelter the defenders from the attacker's superior ranged firepower. If the attacker doesn't have superior ranged fire power it is obviously unnecessary.

The purpose of a forward slope defense is to contest the passage of attackers - especially infantry but also tanks, maneuver elements in both cases though - across wide areas devoid of cover, while they are still too far away to hurt the defenders too seriously. If there aren't any such wide areas devoid of cover, or the defenders can't stop the attackers from crossing what cover there is, or the attackers are so close or so composed (force mix, weapons match ups, etc) that they can hurt the defenders seriously, then clearly it isn't going to work.

Mixes are common, but usually as a minor variant on a basically reverse slope defense. That is, the main body goes on the reverse slope, but an outpost line goes on the crest or forward slope. The outpost line typically uses ranged harassing weapons and preferably stealthy ones (some times one-shot, disposable ones, instead, in ambush and run fashion). The idea, clearly, is to contest the enemy crossing open somewhat, to delay him. It can also help conceal the defense scheme, and provide intel about where the attacker is and where he will try to cross the ridge or other LOS block.

Open defenses typically rely on combined arms asymmetries. Machineguns and mortars, light flak and infantry guns - collectively "heavy weapons" - all outrange standard small arms. If the defenders are also sufficiently dug in, they may be effectively impervious to light artillery support. That means they have a range edge in effective terms. If then sited deliberately with wide expanses of open ground ahead of them, you get the paradigmatic open or forward slope defense.

E.g. a German infantry company with its organic heavy weapons plus an extra HMG platoon and a section of light artillery, dug in with a few log bunkers and trenches, on a modest rise in otherwise open steppe terrain. Typically there is also registered medium artillery. The squad infantry portion of the position defends the second half of the range envelope, but the "weapons" already contest any approach within a kilometer or so of the position.

Now it is quite hard to take such a position with just infantry forces. The organic weapons of a typical Russian rifle battalion - light mortars, ATRs, perhaps 76mm artillery support indirect - are quite ineffective against sufficiently dug in troops. (The bigger mortars are best at it, used in direct fire against a fully located target - which it is by no means trivial to do).

OK, but now change the combined arms situation. Give the Russians half a dozen T-34s. Now the Germans are dumb to stand on a forward slope.

Change it again by giving the Germans 3-4 75mm PAK. Now forward works.

What is driving it is the ranged war match up. Who has "trumps" at long range? If the defenders do, it is dumb to let the attackers close unmolested. If the attackers do, it is dumb to stand under their fire and just get pounded out of existence.

The defender gets to choose, because he picks where to site his defense. He has to estimate the ranged firepower situation. He can be right about it or he can be wrong. Depends on his intel etc.

[Mike Summers]

Heh, I told you he probably had something worthwhile. Thanks, JasonC.

[SteveP]

I may be guilty of overcomplicating the question in my own mind.

In any situation in which one side or the other is known to have superior ranged weapons, the choice falls into what I would consider to be the "obvious" category. It may be that this is the situation so much more often than otherwise, that the question I was asking doesn't really come up that much. It just happens that I have played some battles recently where the two sides at least "seemed" to be about even in that regard (considering also defensive terrain and fortifications in the equation).

At the time it seemed like choosing the "right" line at the supermarket -- whichever way I choose, it always seemed like the other approach might have worked better. That is why I got hung up on the idea of doctrine and probabilities.

Jason's summary did get me thinking about another dimension of the decision that I'd been ignoring: the relative mobility (both ease of movement and a covered path for movement) of any ranged weapons initially placed on a forward slope. If mobility is poor, then clearly putting your money on a forward slope defense carries a lot more risk. On the other hand, if mobility is good, there may be some significant opportunity cost in starting those assets entirely in reverse slope positions. I could see how that analysis might well be a good "tie-breaker" in deciding which way to go.

[Mike Summers]

One of the worst things that can happen to a forward slope defense is the enemy having a healthy artillery barrage available with a clear line of site to the defense. I'm not sure about the historical accuracy of my methods, but more often than not I will defend from a reverse slope, or at the very least, keyholed AT guns to minimize being destroyed by various forms of HE.

[Corvidae]

A forward slope defence is a death trap for the defender.

A ridge top defence is a risky but potentialy useful advance position. ( ATrifles and LMGs in concealed foxholes.)

A reverse slope defence is a solid defence.

[JasonC]

C - try my "Operation Uranus" scenario, the first in that scenario pack. If you think the Rumanians can even attempt a reverse slope defense in such a situation - even in principle, even if the terrain were improved to help it - well, I don't think it will remotely work is all.

Their only real chance is to hold the line of the wire and break as many Russians as possible on it. Once they are through the wire in strength, they can try to mess them up with artillery, but their chances fall dramatically. And if they tried to defend from back in the village-farm area, from within it - they would just be steamrolled flat without the Russians getting their hair mussed.

[Cuirassier]

I find generally that reverse slope defenses usually work better, simply because the defender can usually achieve local odds if the defense is deployed correctly.

However, in some circumstances, I have found that against a good player, neither defense may work. In my experience, this usually occurs if the germans are defending and the russians are attacking with a mech force type. If the germans go forward slope, T-34's easily chew them up, and if the go reverse slope, you are just inviting an SMG company to get within arms reach and outshoot your infantry close up. Either way, the German force will succumb to a properly handled Russian mech one (unless if the Germans have uber tanks), regardless if the Germans are using a reverse or forward slope defense.

[JasonC]

That is a quite common relationship. But the one I was thinking of isn't Russian mech, it is guards infantry and lots of it. The conditions are light snow and fog, at dawn. Visibility quite limited. The Rumanians have entrenchments and wire and the Russians have to come at them across open snow covered steppe, but with first LOS quite close. If the Russian infantry gets to any sort of place from which they can fire back seriously, they readily melt the Rumanian defenders - they have the numbers for it, and limited LOS keeps the odds local. But nobody likes being shot up at 100m in the open or hung up on wire...

More generally, sometimes the cover differential is about all the defenders have, and they have to do whatever exploits it to the maximum. Sometimes they have that and superior range (with stealthy shooters etc). The hardest part is often a long infantry approach without decent cover. Reverse slope defenses are giving up some serious high cards, and they have to get enough back to make it worth while.

[The_Enigma]

Just need to clarfy this, i think it is correct but hell here it goes.

Reverse slope defense, is that not setting just as the hill/ridge slopes down, so that the troops can cover the crest/flat section on top and far off whilst minimising (or at least hoping so) there own casulties via incoming fire due to a hill being in the way?

And not setting up at the bottom of the ridge?

So from that, the blind spot can be the forward slope, i take it from what ive read above that once the attackers get there, the defense is basically buggered as the attacker can sort of rush the reverse side?

So it was mentioned that its someone what better to try and employ a defence of both sides, would this be split squads prehaps.

SMG heavy squads on the reverse side and the riflemen and LMG's on the front?

What would the point be of deploying on the crest/top of the hill/ridge? Are you not more exposed, silhouetted (in real life) etc etc

Is that not the more risky defence?

(although i have used this in game but only when there is some form of cover available, rough ground, trees etc.)

[Corvidae]

I would Think that a reverse slope defence would be just behind the crest, not way at the bottom of the slope.

A reverse slope defence still has to be a defence, it must still be able to engage.

This is what I consider a reverse slope defence

[The_Enigma]

Thought as much, just got sightly confused before when looking through the thread.

[SteveP]

Corvidae and Enigma: You may want to follow Mike's advice and check out Jason's various postings (with a search) on how to set up a reverse slope defense -- which may or may not include a detachment on or over the crest to delay and harass the attacker. My question for this thread was based on a definition of reverse slope defense that is also the case in Jason's postings.

It is my belief that a decision to voluntarily adopt a reverse slope defense (that is, not one which is basically a fallback after being driven from a forward slope position) happened far less often IRL -- even in WW2 -- than probably happens in CM. I think this is because of the desire IRL to deny high ground to the enemy, but also because a reverse slope position often has no line of retreat.

The way things work in a typical CM battle, however, tends to make a reverse slope defense more attractive. For one thing, it is difficult to conduct an orderly retreat in CM from any position that is in LOS anyway. Despite that, my preference is to use a forward slope defense (to take full advantage of any long open terrain) unless there are clear reasons to do otherwise. The purpose of this thread was to get clearer in my mind what those reasons are or should be.

[Broompatrol]

For what its worth:

The CMBB DEMO scenario; Citadel Schwerpunkt is good for practicing reverse slope defense.

Play as Russians. Your guns will be easily destroyed at long range in open and will do little damage to german armor at long range.

The germans have no infantry in this so it is very uncomplicated and you can play with what works.

[Cuirassier]

I would Think that a reverse slope defence would be just behind the crest, not way at the bottom of the slope.

In my experience I have found that a reverse slope defense, using a standard ridgeline as the los block, can have units just behind the crest, as Corvidae suggests, or at the bottom of the slope. Both setups isolate the enemies lead echelons and allow for favorable odds. Of course, one will want advance positions so they can see the enemy on the other side of the ridge.

Normally I like to place units just below the ridge itself, with heavy weapons placed further back and facing inwards. My infantry at the ridgeline this way can fight the lead elements with local odds, and if things get too hot, can then retreat back some to the bottom of the slope, still maintaining the postition.

Of course, there are certain matchups that make a reverse slope defense a bad idea, such as defending against SMG's, or when you are faced with lots of infantry depth (as JasonC mentioned) and fail to destroy it while it sets up in cover on your side of the slope, within easy range of your infantry. Generally in CM though, I favor the reverse slope because it seems to be a superior defense in most circumstances, and cannot be outflanked if anchored on the bottomless pits.

[Cuirassier]

Thinking about JasonC's comments about Uranus scenario, I have thought about two other defensive options that can be related to the discussion of reverse or forward slope defenses. These options are a mobile, fall back and ambush defense, or a concentrated, and more static defense. When I play CM, I usually use the latter, but in a scenario, say where there is moderate cover and it is foggy, thus limiting los, would it be better to employ a defense where you constantly ambush and attrit the enemies lead elements while they are seperated from the main body? In theory I think this would work, since the attacker is unlikely to attack with a heavy front with most of is men online, because of the fear that he might stumble upon a fully integrated MLR which would make short work of the attackers.

Obviously, such tactics wouldn't work all the time, but in a situation where LOS is limited, so the attackers, if in depth, are separated front to back, the enemy could be thoroughly attrited in having to keep his lead elements up to strength. If he picks up on your strategy though, and swithces to a heavy front though, he will likely eat your defense though, since he should have tremendous local odds.

[Corvidae]

Ignore this

[JasonC]

No, placing units just behind the crest with LOS forward still, it called exploiting a bug in CM that treats all HE targets as height zero, and has nothing to do with actual reverse slope defenses.

An actual reverse slope defense puts the hill between the defenders and the attacker's side of the field, completely blocking LOS. A few delaying MGs, a sniper, some listening posts, a light FO - may be forward with LOS, but just enough to see what is coming and maybe delay it a little. The defending main body deliberately avoids LOS to the attackers, rather than seeking it.

Because LOS works both ways, and this ensures the defenders cannot be hurt by the attacker's ranged weapons.

The idea of a reverse slope defense is that none of the attackers has LOS to anything - nor do they have any idea where the defenders are - until some of them reach and begin to cross the crestline, themselves.

At that point, the attackers are sillouetted against the skyline, at very close range to defenders, and none of their friends farther back can help at all.

The defending infantry is on the backside of the ridge. On the slope or at the bottom - how high to "hug" the hill is a key judgment call. It is a "head game" with the attackers and their artillery plan - be where you aren't expected.

The defending ranged weapons - guns, MGs, etc - are typically well behind the defended ridge. On the next ridge back or just a ways across the valley etc. The idea being, they integrate their LOS and fire, and can hit everything on top of the ridge or on the defender's side of it. While being still at long enough range to be well protected from e.g. attacking infantry first onto the ridge.

Sometimes the crest line is also mined. Mines or wire are frequently added just behind the crest line, to block movement forward and off of it, into any sort of cover on the defender's side.

The attacker's side of the hill is simply conceeded to them. But anybody who crosses gets hit by the kitchen sink. (Sometimes mortars or artillery are dropped on the far side, to disrupt dense attackers massing to cross together etc).

[Corvidae]

Ah,, i stand corrected, so my positioning of units just behind the crest is what???

given that its my prefered defence i would like a name for it,

[Cuirassier]

I believe the tactical designation for such a defense is: Corvidae's forward/reverse slope super hybrid defense employing zero height units

[z-warfare]

C's F/RSSHD (emp. O-HU)

[Cuirassier]

Ah, thanks for the excellent abbreviation z-warfare. That makes it very easy to remember.

[JasonC]

Exploiting the crest bug.

[The_Enigma]

May i asy, excellent posts here.

Am sure these will help in future CM games (and any other war game by the looks of it)

*starts a search for other topic and postings which have been mentioned*