Musing on cover, entrenchments and ground hugging in Crossfire

One of the things I would like to do in Crossfire is entrench my men in a wood and get some game benefit. In the standard rules being in a wood, being entrenched, and ground hugging all provide the same level of cover. Usually that is fine, but I’m looking at doing Burma and I expect the associated jungle fighting will require more nuance. So I’ve been musing on how to simulate combinations of cover, entrenchments and ground hugging. I think Lloydian Aspects: Crossfire Probabilities offers a way to distinguish ground hugging from other types of cover, and allows entrenching in the open to be different to entrenching in cover, all without a lot of faff.


The “cover” problem

Before jumping into a solution, it is always worth being clear on the problem.

Crossfire gives a rifle squad 3d6 when firing at an enemy in the open with hits on a 5-6. This drops to 2d6 when firing at enemy that is entrenched, in covering terrain, and/or ground hugging. The to hit remains 5-6. When firing at enemy in a bunker the squad rolls 2d6 and must roll 6 to hit.

So Crossfire offers the same -1d6 cover benefit to troops that are entrenched, in covering terrain, and/or ground hugging. My problem is the “and/or” bit of that. Personally I think ground hugging in the open should offer less cover benefit than being concealed in a wood. I also believe that being entrenched in a wood should provide more of a cover benefit than when skirmishing through a wood or being entrenched in the open. In WW2, for example, experienced troops favoured entrenching on the tree line, just inside the wood. It provided better concealment than in the open only a few metres ahead of the tree line.

Entrenched in Woods and Ground hugging
Entrenched in Woods and Ground hugging

But making these tweaks in Crossfire is tricky. Going from 3d6 to 2d6 to 2d6 hitting on a 6 are simple but these are big jumps. Is it possible to get more fine grained control without replacing Crossfire’s 1d6 with a 1d10?


Lloyd’s experiment with dice variants

Nikolas Lloyd’s page on Crossfire Probabilities explores alternatives to the normal Crossfire mechanisms e.g. 2.5d6, 3d6+1P, and 3d6+2P. All of these variants use six sided dice. Lloyd did the maths and worked out the relative potency of these options. You can check out his website for how he did this.

Crossfire dice variations based on Lloydian Aspects
Crossfire dice variations based on Lloydian Aspects

These are the variants I consider in this post:

  • 3d6 and 2d6: In red are the standard Crossfire 3d6 in the open and 2d6 into cover.
  • 2d6(6): The standard Crossfire bunker rule is in yellow. In this case roll two six-sided dice and count rolls of 6 as hits.
  • 2.5d6: The Lloydian variant in blue adapts the bunker rule. 2.5d6 means roll 2d6, hitting on 5-6 as normal, but then roll a third die that only hits a 6.

Note: I haven’t considered the penalty dice variant (in green) because the 3d6+1P gives similar results to other alternatives and 3d6+2P gives much worse results.

To solve the core problem I need to find a pattern in these dice variants and I think I’ve found one. The normal rules and the 2.5d6 variant seem to provide a nice 5 point scale of effect. Lloyd has a big table of Crossfire Probabilities, but I have extracted the five data points I’m interested in. PIN is the percentage chance of getting a Pin, Suppress or Kill result. SUPPRESS is the chance of a Suppress or Kill result. MID is the middle point between PIN and Suppress – this value is used for the diagrams.

Die Roll PIN SUPPRESS MID
3d6 70.37 25.93 48.15
2.5d6 62.97 18.52 40.74
2d6 55.56 11.11 33.33
1.5d6 44.45 5.56 25.00
2d6(6) 30.56 2.78 16.67

Now I look at a couple of options that use that pattern.


Option 1: Potential house rule for entrenched in covering terrain

So my first option for a house rule would be to take one step on that progression for each of grounding hugging, being entrenched, or being in covering terrain.

Option 1 - Possible house rule for entrenching in cover
Option 1 – Possible house rule for entrenching in cover

Assuming a stand is shooting at a target that is [the example is a rifle squad]:

  • In open: normal in open [3d6]
  • One of ground hugging, entrenched, or in covering terrain: 1d6 only hits on 6; other dice hit on 5-6. [This is Lloydian variant 2.5d6; so 2d6 hit on 5-6 and 1d6 hits on a 6]
  • Two of ground hugging, entrenched, or in covering terrain: Normal -1d6 for cover [2d6]
  • All of ground hugging, entrenched, and in covering terrain: -1d6 for cover and, in addition, 1d6 only hits on 6 and the other dice hit on 5-6. [This is Lloydian variant 1.5d6; so 1d6 hits on 5-6 and 1d6 hits on a 6]
  • In a bunker: Normal bunker rule so -1d6 for cover and all dice only hit on 6 [2d6 and hit on a 6]

Pros

  • Elegant and based on a simple principle (down a step for each cause of protection)
  • Allows interesting combinations e.g. ground hugging in an entrenchment

Cons

  • More times in a game when the normal rules don’t apply.
  • Invites new rules e.g. cannot fire if ground hugging in an entrenchment
  • Got to remember the rules

Option 2: Potential house rule for entrenched in covering terrain

I’m looking for a pattern that that I can use to solve the cover problem. I think I’ve found one. The normal rules and the 2.5d6 variant seem to provide a nice 5 point scale of effect.

Option 2 - Possible house rule for entrenching in cover
Option 2 – Possible house rule for entrenching in cover

Assuming a stand is shooting at a target that is [the example is a rifle squad]:

  • In open: normal in open [3d6]
  • Ground hugging and in exposed terrain (i.e. not in covering terrain): 1d6 only hits on 6; other dice hit on 5-6. [This is Lloydian variant 2.5d6; so 2d6 hit on 5-6 and 1d6 hits on a 6]
  • Either entrenched or in covering terrain: Normal -1d6 for cover [2d6]
  • Both entrenched and in covering terrain: -1d6 for cover and, in addition, 1d6 only hits on 6 and the other dice hit on 5-6. [This is Lloydian variant 1.5d6; so 1d6 hits on 5-6 and 1d6 hits on a 6]
  • In a bunker: Normal bunker rule so -1d6 for cover and all dice only hit on 6 [2d6 and hit on a 6]

Pros

  • In most cases the normal Crossfire rules apply e.g. entrenched in the open or in covering terrain.
  • But allows the combinations that I’m particularly interested in e.g. entrenched in covering terrain

Cons

  • Less elegant because not based on a simple principle
  • Got to remember the rules

Conclusion

On balance, I prefer option 2. Leaves most things unchanged. But precisely addresses the problem as I see it i.e. (1) entrenched in the open is worse and (2) entrenched in covering terrain is better. All of this without a lot of faff. Okay, maybe a little faff, but not a lot.

Note: If you have interested in numbers, then you might be interested in my Crossfire Probabilities: Percentage Success in each Die Roll Mechanism.

6 thoughts on “Musing on cover, entrenchments and ground hugging in Crossfire”

  1. As a general rule I only give cover benefits for soft cover against direct fire and not mortars/artillery, so “digging in” in a wood protects against area HE fire. It is a while since I played CF so I can’t remember how woods affect If.

    Reply
    • In the normal game, Woods provide cover to both direct and indirect fire. There are arguments for and against Woods providing cover against indirect fire. On balance I favour Woods = cover. But that of course then raises the problem of where is the value of the entrenchments.

      Your suggestion neatly dodges that problem. Woods, in your scheme, become like HTD in-season fields, i.e. provide cover to direct fire but not to indirect fire. And entrenchments suddenly have value be providing cover to indirect fire. Nifty.

      Reply
  2. I like option 2 and I will try it out. I assumed that soldiers in cover are taking the best positions possible, including hugging the ground, which is reflected in the -1D6. I’m curious on how you implement entrenchment. Is that part of your scenario design and included as part of the setup or do you allow entrenching in the game? If setting a scenario based on points, what is an entrenchment for a platoon worth?

    Reply
    • Some of my scenarios give the defender, “As many entrenchments as they want” e.g. Village P, Line N-M, 2 Companies a side, and 2-3 Companies a side.

      In game entrenching is handled via “Ground Hugging”. So entrenchments are chosen before game and deployed hidden at the start of the game. These are free (0 points) because the defender can place troops in terrain and take no entrenchments. The entrenchments, if chosen, are there for flavour.

      If I can find a while to give entrenchments value in the game, separate from terrain, then they may be worth assigning points to.

      Reply
  3. I’ve tried the loydian .5 die and liked it in terms of gameplay, but it did slow us down somewhat, when resolving group and crossfires where we would normally have one colour of die per stand and roll everything at once. Having different target number requires visually different dice imho, or rolling them separately. I did consider making a custom set but never followed through.

    I have tried using d12 as d6 with .5s on them, the basic hit then required a 9 or better, this can be raised to 10, 11 or 12 to represent different cover. MID probabilities for 3d12 hitting on 9, 10, 11, 12 are: 48.15, 36.72, 24.77 and 12.47.

    Reply
    • I would be concerned about slowing the game. I was intending to have different coloured dice for the “6 to hit” but I can imagine fumbling around looking for them. SoI would only use this as a Scenario Specific Rule, not a general House Rule. When a scenario needs it, I’ll include it.

      Reply

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