Land combat

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  • Organization: A unit's capacity to stay engaged in combat. Once this reaches "1" they will retreat. Organization is affected various factors including unit type, technologies, and Officer Ratio.
  • Effectiveness: Assigned to both attack and defense, this is a modifier of "base" values for attacking and defending. Effectiveness is determined by leaders, weather, terrain, etc.
  • Combat width: The space a unit occupies on the front line of battle.
  • Toughness: A unit's ability to prevent damage from enemy fire while attacking.
  • Defensiveness: A unit's ability to prevent damage from enemy fire while defending.

In February 2011, it has been discovered that since Hoi 3 v1.0 up to SF 1.4d, a bug rendered Toughness, Defense and similar damage preventing stats completely useless - all fired shots hit the target! Keep in mind that a lot of balancing would have been done using this technique, so, while it does not break game balance overpowering the enemy is worth far less worth than it should be - source:

From beyond that point, the bug appears to have been fixed.

  • Soft Attack: Attack power against non-armored targets.
  • Hard Attack: Attack power against armored targets.
  • Softness: The percentage of a unit that is not armored.
  • Officer Ratio. Affects combat delay(?) and organization.
  • Stacking Penalties. Too many divisions in a province reduces combat effectiveness.

Combat resolution

Combat is measured by one hour "rounds". Each round has five phases: firing, damage, shattering, push back, and reorganization. Combat has an "attacker" and a "defender" based on whichever side initiated combat.

Stacking penalty

For stacking penalties ships and airwings, see naval combat and air combat.
The following is extracted from a forum post by blu emu)[1]

Stacking penalties depend on the number of Divisions (not Regiments) involved in the battle, and on the number of directions of attack (attack vectors). Converging attacks... e.g.: attacking from several provinces into one enemy province, or defending a province against an attack from enemies in several provinces... allow a higher stacking limit and give a lower stacking penalty.

Units committed to the attack still count towards the stacking penalty, even if they are "in reserve" because there are too many of them to all fight at once on the given frontage. Units in a DEFENDING stack are always considered "committed to the battle", hence they all will count towards the stacking penalty.

 frontage = 5 x ( #_of_attack_vectors + 1 )

e.g.: an attack from four provinces has a frontage of 5x(4+1)=25.

 allowed units in a combat = integer ( frontage / unit width ) + 1

e.g.: a frontage of 25 (a four-province attack) with 3-width Divisions such as INFx3/ARTx1 allows room for integer(25/3)+1=9 Divisions to participate.

 stacking limit = ( 3 x number_of_attack_vectors ) + 1

e.g.: attacking from four provinces into one allows (3x4)+1=13 Divisions in the attacking stack, without any stacking penalty. Note that four of them will be "in reserve", since there is only room (on a frontage of 25) for nine of them to attack at once... again, assuming that they are width-3.

 stacking penalty = -100% x ( 1 - ( 0.9 to_the_power_of ( #_of_attacking_units - stacking_limit ))) + theatre_commander's_skill

e.g.: attacking with six 2-width units (such as INFx2/ARTx2) in a single-province attack (frontage=5x(1+1)=10) gives you a stacking limit of four Divisions ((3x1)+1=4), hence an over-stack of two Divisions and a stacking penalty of -19% less the theatre commander's skill... a skill-3 theatre commander would reduce the penalty from -19% to -16%.


Main article: Combat width
In combat, divisions join as a unit in until the used width equals exceeds the available frontage. This can result in an overflow; for example, if two divisions of 4 width are in a combat where the total allowed frontage is 10, a third can join in bringing the total width to 12. It is not known yet what the join order is.

General skill

Leader skill at the theater level will be applied to reduce the co-ordination penalty for a given number of units. The co-ordination penalty is 1% for every division over 12 engaged in a battle. For example, a leader with a 5 skill level allows 17 divisions to be engaged in a battle without co-ordination penalty. 'Stacking penalty experiments'.

TFH update: Every land battle now begins with the leaders on each side picking a particular tactic to use, which grants their side certain bonuses in combat. Many tactics also have a counter-tactic, which if used against them will nullify their effects. If a tactic has been countered it will have a broken looking grey arrow instead of the normal smooth black one. The leader with the higher skill has an additional advantage in picking a tactic that will counter his opponent, in battle the leader with the higher skill has a highlight around his picture so he can be easily identified. Besides leader skill and traits, doctrines on either side, units present and aggression settings affect what tactics are picked.
Aggression Players can use the Aggression slider to manually control leader choices in the direction you set (In the case of AI controlled units this is handled by their Stance). You can set Aggression at any HQ level and your leaders will look to the nearest HQ above them in the chain of command to take their stance from them. You can simply set this at the Theatre level, or you can tweak every Corps HQ on the Eastern front if you so desire. You can even mix & match, for example you might set a Theatre that’s on the defensive to use defensive tactics, but set your counter-attacking Armoured Corps to high Aggression.

Higher Aggression settings will tend to make leaders pick higher risk Tactics which tend to win battles faster but take higher losses, while lower settings will make leaders use delaying tactics to draw out battles with minimal losses. Do keep in mind that this only weighs the choices of your leaders though, so you may find Rommel is still launching Blitzes even while set to low aggression.

Firing phase

This is where all unit damage is delivered by divisions on the front lines of combat (see combat width for more information). The following sequence of events occurs in the firing phase:

  1. Each side of the battle randomly targets an enemy division, and will keep that target for the entire round.
  2. Each side of the battle will choose to attack the "soft" or "hard" aspect of its target based on its softness: a target with 70% softness has a 70% chance of receiving a soft attack.
  3. Both sides of the battle will fire at each other in sequence. The number of shots fired is based on the attack values, modified by attack effectiveness, rounded down.
  4. The target then defends against the shots fired:
    1. Each division has defense points for the round, which are used to determined it the shot is a hit or a miss. The defender's "defense points", are its defense value multiplied by the defensive effectiveness, rounded down. When defending units fire shots back at the attacking unit, the attacker uses "defense points" from its toughness value multiplied by defensive effectiveness.
    2. Each division will use one defense point for every shot fired at it.
    3. If a division has not used all of its defense points in the round, then each shot directed at it has a 70% (FTM & TFH) chance of missing. If it has used all of its defense points, each shot has a 48% (FTM & TFH) chance of missing.

Example: A German infantry division (3 infantry brigades) is attacking a Polish militia division (3 militia brigades). The battle takes place in clear weather, on plains terrain, and there are no leader bonuses for either side. Firing Phase:

  1. Both divisions target each other.
  2. Both divisions are 100% soft, so softness values are used.
  3. The German infantry division has a total soft attack of 6, while the Polish militia division has a soft attack of 2. Both have 100% effectiveness because no modifiers (weather, terrain, leaders) are present. Thus, the Germans fire 6 shots in a round, while the Polish fire 2 shots.
  4. The Polish militia division has a defensiveness of 13 while the Germany Infantry division has a toughness of 9. Practically, this means that both sides will never exceed the defensive points of the other side, thus all shots fired will have an 70% chance to miss.

Result: In each round, the German Infantry will tend to hit at least 1 shot, while the Polish militia will hit 0 shots a lot more often. Averaged out over time, the Germans will hit with 9 shots in 5 hours (1.8 shots/hour), while the Polish will hit with 3 shots in five hours (0.6 shots/hour).

=== Damage ===This area might need to be updated. Damage is calculated based on the number of hits in the round. For a division at 100% strength, each hit will cause:

  1. Strength loss is caused by a "2 die size", meaning it will randomly cause 1 or 2 points strength loss. This is "modified" by 1.5 times. Thus, each shot will cause either 1.5 or 3 strength loss. In this sense, the average damage each shot causes is approximately 2.25. This number represents actual casualties, as opposed to strength percentages.
  2. Organization loss is caused by a "3 die size", meaning it will randomly cause 1, 2 or 3 points lost in organization. This is then "modified" by 0.1 times. Thus, the each shot will cause either 0.1, 0.2, or 0.3 organization loss in the target. In this sense, the average organization loss each shot causes is approximately 0.2.

For more information, visit Understanding combat resolution on the forum. Note: Damage is modified by the strength of the division. It is presently unknown how division strength modifies damage caused.

Example: Continuing the German vs. Polish example from above. These numbers are based on averages:

  1. The Germans have hit with 43 shots in the first day of battle (from their average of 1.8 shots per hour), while the Polish have hit with 14 shots (from their average of 0.6 shots per hour).
  2. The Germans have inflicted a total of 97 Polish casualties, while the Polish have killed 32 German soldiers.
  3. The Germans have caused an organization loss of 8.6, while the Polish have caused an organization loss of 2.9.

TFH update: Armour and Armour Piercing

All tank type brigades, and armoured cars, now have an Armour value, and all land combat brigades, plus a few support, now have an Armour Piercing value. Whenever an Armoured unit is in combat any unit attacking it must test its Piercing value against the defending unit's Armour value: If the defending unit's Armour value is higher the defending unit takes half damage from the attack and the defending unit also does increased Org damage against the unit attacking. If the Piercing value of the attacker is equal or higher than the defending unit's Armour value then there is no effect and combat proceeds as normal (i.e. the defending unit takes normal damage and does normal organizational damage to the attacker). Both Armour and Piercing work by checking the best value in a division, it is not averaged. As a rule of thumb, at equal tech levels Light and Medium armour cannot be Pierced by Infantry, but will be by Anti-tank brigades, while Heavy armour will not be. Armoured cars, on the other hand, will not normally have any advantage over Infantry unless they have a couple of tech levels over them. This means there is now an arms race between Armour and Armour Piercing weapons, both between tanks and AT/tanks, and should make AT units more useful as well as offering some more advantages to Heavy and Super Heavy armour units.


After each round of combat strength and organization is checked. If most of the strength or organization has been lost then the the unit will shatter and be forced to withdraw to the country's capital to be rebuilt. If a supply line is not available then the unit will instead surrender. Leadership, Officers, and unit experience protect against shattering.


This occurs when there has been a long battle and the defender has suffered serious losses and will automatically occur when a province is taken by a new controller. The defender is forced to withdraw and the infrastructure is damaged. Any building in the province will be damaged. All units involved in defence, including those that did not actually get into the battle as they are still waiting as reinforcements, will be forced to withdraw. So a defending unit might lose its organisation and retreat even though there are perfectly healthy units in the province that were sent to reinforce it during the battle. Those extra units will also have to retreat if they were unable to move out of the reinforcement box and into the actual battle.


During a battle, reserve units have a chance to move forward and engage in combat.

Moving the cursor over the reserve unit displays that chance, such as 0.40%, 1.20%, and so forth. If space is available at the front, this is the percentage chance that the unit will enter the battle within the next hour.

Reported modifiers to the chance of reinforcement involve the corps-commander skill level, current unit organization value, the (existence of) the reinforcement chance doctrine, and if the player has a political leader with a "reinforcement chance" modifier.

Finding the chance of a unit joining the battle within “x” hours does NOT involve taking the probability of joining per hour and multiplying that by “x”. That would give a result that is too high, since a unit can join a battle in hour 3 only if it has already failed to do so in hours 1 and 2.The calculations must allow for a "diminishing returns" factor; hence, it involves an exponential term to a base value between zero and one, exclusive.


1. First, calculate the chance of the unit NOT joining per hour, and raising that result to the power of hours in the period under consideration, “x”.

2. Finally, subtract that result from one, (x100%), yielding the chance of the unit joining the battle within “x” hours.


A unit with a 0.5% chance per hour of joining combat, means it has a 99.5% chance (or 0.995) of NOT joining combat each hour. Finding the odds of that unit joining the battle over a period of say, 24 hours involves taking the chance of the unit NOT joining combat and raising it by the period (in hours), 24. This result (0.995^24 = 0.8866) yields an 88.66% chance of the unit NOT joining the battle that day. Subtracting the result from one (1 - 0.8866 x 100% = 11.34%) means the unit in question has an 11.34% chance of joining combat in the first day.

A unit’s current organization value seems to have a large impact on the reinforcement chance. In the early war period, units with low organization values may have a .1 or .2% reinforcement chance, while late in the game a unit with a high organization value may have a 6% or greater chance of reinforcement.

====Combat Factors==== (Values can be found in the defines.lua file)

  • Weather
  • Terrain
  • Combined Arms
  • Entrenchment - 2% per day, each day a unit has been entrenched, up to a maximum of 20% (ten days). Entrenchment is automatic for all stationary units.
  • Supplies
  • Fortification - 9% penalty to the attacker per level of fortification, up to a maximum of level 10, i.e. 90%
  • Night - 50% penalty to both sides
  • Leadership
  • Combat events
  • Stacking Limits - The co-ordination penalty is 1% for every division over 12 engaged in a battle, modified by the Theatre Leader's skill.
  • Territorial pride
  • Specialist Equipment
  • Envelopment & Encirclement -
    • Envelopment is a penalty applied to the defenders if they are getting hit from 3 or more "directions" at once, 10% per province. So 3 directions = 10% penalty, 4 = 20, 5 = 30, and so forth. Extra directions can also be added if a Naval landing or paradrop is added on the target as well.
    • Encirclement is a penalty to the defenders if they have NO land-based friendly province adjacent to them. For this penalty, it is NOT necessary that they be getting hit from all provinces; as long as they have no province (not counting water) to retreat to, they will suffer a 10% penalty, period.
    • If a unit is surrounded AND being attacked from all sides, both penalties will be seen. This is one of the most effective, if not in some cases the only, way to uproot stubborn defenders from well-fortified provinces.
  • Shore Bombardment - up to 25% penalty to the defender(Only?) from ships next to the province.
  • Dissent.
  • Paradrop - 50% initial penalty in the province where they land.
  • Amphibious Assault - there is a huge penalty to mobile units.

Combined arms

The entire division must have a softness rating between 33% and 66%. This means pure infantry and pure armor divisions will not benefit from the combined arms combat benefit of base +20% (plus modifiers). On the division build screen, the teddy bear will show you the softness of your combinations, with the teddy bear lighting up a little when you have reached the CA thresholds.

Said modifiers can significantly increase combined arms combat effectiveness. Panzer Leader increases CA by +10% (+5% for the corps commander, +2.5% for the army command, etc...) and +10% added for the combined arms tech under the land doctrine Superior Firepower tree. These combined arms bonuses stack additively, so a division of two L Arm and 1 Mot Inf led by a panzer leader with a corp HQ in range with a Lt Gen who also has Panzer leader will grant a +35% bonus to the division during combat. +20% base, +10% Division General, +5% Corps General = +35%.

  • Summary of CA combat effectiveness factors when in HQ range:
  • Base Combined Arms bonus: +20%
  • Combined Arms Warfare Doctrine: +10%
  • Mj Gen (Div lvl) Panzer Leader: +10%
  • Lt Gen (Corps lvl) Panzer Leader: +5%
  • Gen (Army lvl) Panzer Leader: +2.5%
  • FM (Armygrp lvl) Panzer Leader: +1.25%
  • FM (Theater lvl) Panzer Leader: +0.625%
  • Net possible effect = 49.30%

Note that if you are out of range of one HQ level such as Army, the next HQ level uses that fraction instead. Only the number of intervening HQs counts. Not the HQ's absolute place in the hierarchy.

Changes introduced with Their Finest Hour

TFH Division Build screen, CA bonus in bottom right-hand corner

Unlike in previous versions of HoI3 units where units received the Combined Arms bonus when their Softness was in the 33-66% range, in TFH the Combined Arms bonus is now based on combining different unit types within a Division. You now also get a varying size of bonus depending on how many different unit types you combine. Unit types for this purpose are:

  • Infantry: Cavalry and all Infantry types besides Militia (including Motorised, Mechanised and Garrison)
    • Infantry is the base unit and offers no bonus in itself. However, no unit without infantry will receive a CA bonus.
  • None: Militia and Military Police.
    • None offers no bonus.
  • Armour: All tank types, from Light to Super Heavy.
  • Artillery (Indirect Fire): Both Rocket and Regular Artillery, including Self-Propelled types.
  • Direct fire: Anti-Tank, Tank Destroyers, Anti-Air, and Motorised AA.
  • Support: Engineers and Armoured Cars.
    • Artillery, Direct Fire, and Support each give a 5% bonus.
    • Armour is also 5% initially, but once the Combined Arms Warfare tech is researched their bonus is raised to 15%.

Infantry (including motorised infantry) is the key to combined arms - no unit without an infantry brigade will receive any CA bonus. Aside from that, brigades may be combined freely in any legal combination. Bonuses from multiples types stack, but multiples of the same type DO NOT stack. E.g.:

  • INF + ARTY = 5% bonus.
  • INF + 2 ARTY = 5% bonus.
  • INF + ARTY + TD = 10% bonus.

On the division build screen, every brigade is a certain colour. Only brigades of different colours add to the combined arms bonus. There is an additional box below the division’s stats which shows how much of a bonus this unit will receive.

  • Infantry: Orange
  • Armour: Purple
  • Artillery: Red
  • Direct Fire: Blue
  • Support: Green

Territorial pride

This modifier, introduced in Semper Fi, gives a bonus to combat efficiency for Axis and Soviet units fighting for their cores. Territorial pride is a relatively fixed modifier, which can only be increased by three Strategic Effects

Combat vs. support brigades

Brigades with a nonzero width are considered Combat Brigades. They have 3000 Strength. These brigades will always beat HQs (that don't have any brigades attached to them directly) and Support Brigades.

Brigades with zero combat width are considered Support Brigades. They have 1000 Strength.

Support brigades must be attached to a division with Combat Brigades to participate in combat. They can't win a combat by themselves and will only be shown in the reinforcement/support section of a combat screen if they are on their own.

Support attack

This function is used to increase your odds of winning the battle without having to move into the province under attack. If you click on this function it will retain it until you give it further orders. If you give this command after an attack has occurred it will finish the order after battle. The order is better given before the battle starts, otherwise the unit in the support attack will be added as a reinforcement and have to wait to join the battle (if at all). Support attacks are subject to combat delay. However, because the units are not fully engaged in combat, they recover from the delay faster, which allows you to move sooner to the next province. Units that are out of supply may be given support attack orders but won't execute them unless they are given some supplies.

Attack delay

After combat, units will experience a movement delay of 168 hours (7 days). This delay can be reduced by researching Operational Organization. For each level delay is reduced by 24 hours. Delay is also linked to officer ratio: Any ratio over 100% up to 200% (officers are capped at 140% in 2.04) decreases the delay, and any ratio below 100% increases the delay.

  • Attack delays are reduced every hour during a battle to a minimum of one.
  • Breakthroughs reduce attack delay.


- Retreating units ignore fuel status for movement speed. They retreat two(One?) provinces and if there are no friendly provinces to retreat to (i.e. they are surrounded) then they are destroyed.

More Information

For more information, see Combat strategy