Land Combat Resolution

[The Rock Doctor]

This is an overview of the land combat system I use when moderating, for the purposes of the ongoing discussion about land unit costs and for general info.

The system is based on GDW's Third World War series, and a few snippets may in fact be direct quotes from their rules and modules - so all due credit to them for that.

I will add additional details as time permits.

This applies to division/corps scale combat. 

1)  Scales

Time:  Alternating turns of 1 week (exception:  discrete events such as amphibious landings may be considered to last only one or more days).  Aggressor goes first.

Map Divisions:  Hexes of 45 km are the standard map division. 

2)  Unit Stacking

Typically limited to one corps-equivalent per hex.  Due to logistical constraints, only a semi-corps/division can stack in a hex if the units belong to more than one allied nation.

Attackers and defenders can not occupy the same hex.

3)  Movement

Infantry and Light/Specialist Infantry units have a movement factor of 6.
Cavalry units have a movement factor of 9. 
Armored and Motorized (1920) Infantry units have a movement factor of 12.

The active side conducts all movement, then combat is resolved.

4)  Morale

"Morale" refers both to a unit's general elan and its proficiency at making war.  Each unit is assigned a generic numerical figure based on its morale:

Mob/Civilian/Non-combatant:  1 - 3 (Moderator determined, depending on circumstances)
Green:  4
Regular:  5
Elite:  6
Veteran:  7

5)  Disruptions

A unit takes damage, or disruptions, as a result of combat.  Each week of combat can cause zero to several disruptions, depending on the intensity and outcome of the fighting.  A unit's morale is reduced by one for each disruption incurred in action.  When its morale reaches zero, the unit is combat ineffective and can not voluntarily attack or advance (withdrawn from combat, it can gradually make good its losses).  If the unit's morale goes below zero, it is destroyed outright.

6)  Zones of Control

A corps or semi-corps ("division") projects a zone of control into the six hexes around it, plus its own hex.  A brigade exerts a zone of control over its own hex only.

Units must expend an additional movement factor(s) to enter a hex with an enemy Zone of Control projecting to it.  This reflects a need for cautious, tactical deployment rather than "road march".

Zones of Control are also relevant when determining the effects of partisan activity.

7) Combat

Combat takes place at the end of movement; if a unit has not expended all of its movement factors to enter the combat, it forfeits the remainder.

A single unit may attack or be attacked once per turn.  Each attack must be directed at the units within a single hex.  All units attacking that single hex attack together, and may do so from one or more adjacent hexes.

Units of allied nations may attack together. 

Calculating Odds:

-Divide the total combat strength (that is, the "5" of "5/3") of the attackers by the total strength of the defenders, rounding down to the nearest whole level (or 1.5:1).

-Determine the total artillery numbers (that is, the "3" of "5/3") of the two sides and divide the higher by the lower.  If greater than 2:1, shift the odds one level in favor of whomever has more artillery.  Shift another level if more than 4:1.

-Determine the average morale of the two sides and divide the higher by the lower.   If greater than 2:1, shift the odds one level in favor of whomever has higher morale.  Shift another level if more than 4:1.

-If appropriate, shift the odds one level in favor of whomever has an information advantage (more cavalry, aerial scouting, secret plans) and/or a technological advantage (first use of tanks!)

-Apply topographic modifiers (which always favor the defender).

-Determine the final odds, and roll a D6.  Lower rolls favor the defender; higher rolls favor the attacker.

Combat Results:

In the combat results table, the value to the left of the slash applies to the attacker and those to the right apply to the defender.  Results are applied to each and every unit on that side.  Possible results are:

-D, 2D, 3D, 4D:  Every unit participating in the battle sustains this many disruptions to their morale.  Units reduced to zero morale can not attack.  Units below zero morale are eliminated and removed from play.

-E:  Every unit participating in the battle is eliminated and removed from play.

-EX:  All defending units, and attacking units with a total strength of at least the same value as the defending units, are eliminated.  Remaining attacking units receive one disruption.

-R:  Retreat two hexes.

Sample of the Combat Results Table:

Roll/Odds:	1:1	1.5:1	2:1
1	2D/-	2D/-	D/-
2	2D/-	D/-	D/D
3	D/-	D/D	D/D
4	D/D	D/D	-/R
5	D/D	-/R	-/DR
6	-/R	-/DR	-/2DR

[maddox]

I agree, just as sea warfare shld be done with an adapted excisting system, land war could be done with an excisting system. We even can change the rules concerning armies. [size=8t](This is a bit trickier with Springsharp)[/size]

[The Rock Doctor]

Bump.

[Kaiser Kirk]

I have this bad feeling that if I comment on this once, I may wind up commenting a great deal.

The system described is adequate for smaller set piece battles, but I think would be flawed for fluid battles, particularly in the larger scale situations we have here.

Several things seem lacking.
One is scouting. While "information advantage" is listed, this would vary across the front. With our small "brigades" of ACs, our Cavalry corps, and scout aircraft, scouting can be done in several ways and would almost form a separate battle, with the results dictating how much useful information makes it to the commanders on the ground. This would generate the ""information advantage"  modifier.

Then there is that troops will not have their entire mass at the point of attack initially. In particular, the larger artillery is slower to bring up and deploy, and may not be deployable in some weather/terrain combinations. Having conventional 150mm guns in mountains or deep mud may render them simply decorative.

Light units have the advantage of being more mobile and capable of getting their gear to a useful point.

So I would have several phases for non-set piece battles.
1. Scouting
2. infantry meeting engagement
at this point the amount of the combat formation engaged would be some random %, with more arriving as the battle went on.  Say 20-50% at this point and +20% each "step" after.
3. infantry + lt. art
4. infantry + lt. art
5. infantry + md art
6. infantry + md art
7. infantry + hvy art
8-10 "

Motorization at 1910 levels moves art up 1 notch, at 1915 levels, up 2 notches.
restricted terrain, and/or poor weather, would delay/prevent it.

Fortifications - Civil-war style breastworks can go up in minutes, but with most TOE including 75mm QF shell guns, they are ineffectual.  However, trenches and log revetments can also be quickly constructed. Rommel even took to bringing empty sandbags to be filled even faster. Troops on the static defensive will quickly become more difficult to dislodge.  Overtime, these become WWI style trenches.

I think at some point field fortifications should be treated as reducing the attackers artillery value as well, perhaps negating the light artillery, much as french 75s were largely withdrawn in WWI.   

More elaborate fortifications-fortified lines- would negate light & medium artillery, while true fortresses would be substantially immune to standard infantry artillery of their era. I have read that 9.2" guns were generally about the largest for horse drawn, so pre-motorized fortresses were built to defy projectiles up to that size.

Supplies : Supplies are boring but vital. After a couple sharp engagements, troops are pretty much dated light infantry without good supply lines. Non-motorized troops are relying on railroads and horses.

Most of Navalism's terrain is poor in railroads.

Which means horses.... Ala Napoleon...who broke his armies into Corps and marched by parallel road systems as a result. Hence the stacking limit discussed.

However, if you have a railhead, or are adjacent to one, exceeding that stacking limit should be doable. Good supply would be available within about 1 weeks ground travel of a railhead or depot.

Even with motorization this doesn't change too much, as trucks are innefficient mass movers compared to trains.

Casualties : Somewhere between 10% and 20% is generally enough to cause troops to break and fall back. More may be taken in retreat, but morale checks should be made once casualties get to ~8%.

Disruption :  Distance from supply routes/ depots, time in field, past success/failure. Generals?

There, have some alumagel for the brushpile

[Vukovlad]

Being a lurker it may not be my place to comment but for fairly good rules on land and air combat I would suggest using the rules from GR/D´s Great war series (available at http://hmsgrd.com/greatwarseries.html).
Although not perfect cover most situations and unit types that occur in this time period. The drawback is that the mod have to use a new system.