Most warfare is conducted on land.
A theater is an area in which military events are taking place. Each theater has its own set of command groups.
- Osobny artykuł: Command group
A command group is a collection of divisions that can be lead by a commander. A command group is tied to the theater in which it operates.
Command Groups can be assigned to a front and given orders through the battle plans interface.
Troops can be transported across water and between two friendly ports. When a division is standing at a port, simply right-click another port to have them attempt to transport themselves there. Transporting troops require s convoys and if you do not have naval supremacy over the sea region, you may suffer casualties.
To launch a naval invasion, the battle planner needs to be used. The mission "Naval Invasion" is the 1st one on the left, with an anchor icon. As the tool tip says, choose the port used for the start of the invasion then the costal province where the landing is planned. Naval supremacy is required in all of the sea zones crossed for the invasion. The plans then need to be prepared for a number of day that increase with the distance travelled during the invasion and the number of divisions affected to the invasion.
- Maximum speed. The division travels at the speed of its slowest combat battalion. Support battalions are not counted in this calculation; they are assumed to have the same mobility as the rest of the division.
- HP. Known as "strength" in previous games. HP represents how much a unit can take damage before it is destroyed. Support battalions have about 5 HP, infantry combat battalions have about 10 HP, and armored battalions' HP depends on the type, for example Heavy Tanks have 15 HP. HP of the division is the sum of all its battalions. When a division takes damage to its HP, the combat stats are reduced proportionally: For example, a unit at half of its maximum HP can only use half of the maximum possible attacks or defenses in combat.
- Organization. Organization indicates the readiness of a unit to perform combat. A unit without organization cannot operate as it is supposed to, and such unit cannot stay in combat or move properly. The organization of a division is the average of the organization of the included battalions. See also Land units#Organization.
- Recovery rate. Known as "morale" in previous games. The speed at which the division regains organization: hourly increase in organization when the unit is not in combat.
- Reconnaissance. High reconnaissance increases the chances of a unit to pick better combat tactics in a battle.
- Suppression. Ability to suppress local resistance.
- Weight. How much the unit weights. Affects the number of transports the unit needs.
- Supply use. How many supplies the unit uses per day.
- Reliability. Reliability reduces the chance of breakdowns and accidents. Reliability comes from support battalions.
- Trickleback. Trickleback represents the proportion of combat casualties that are saved and returned to manpower pool.
- Exp. loss. How much experience is lost when unit takes casualties.
- Soft attack. Represents the ability of a unit to attack soft targets, that is, targets without armor or with very little armor, such as infantry. In combat this stat gives the number of attacks the unit can make against a target with low hardness.
- Hard attack. Represents the ability of a unit to attack hard targets, that is, armored targets, such as tanks. In combat this stat gives the number of attacks the unit can make against a target with high hardness.
- Air attack. Represents the ability of a unit to attack air targets, how much the unit can do damage against airplanes.
- Defense. Known as "defensiveness" in previous games. Represents the number of defenses the unit has when defending, that is, how many attacks it can avoid. When unit has no defenses left, it is more probable that the unit is hit when in combat and can not hold the defense as well.
- Breakthrough. Known as "toughness" in previous games. Represents the number of defenses the unit has when attacking, that is, how many attacks it can avoid. When unit has no defenses left, it is more probable that the unit is hit when in combat and cannot keep the offensive going as well.
- Armor. Representing the armor of a unit, if the armor value is higher than enemy's piercing value, the unit takes less damage in combat. Higher armor will also increase the units attacks in combat, as it can move around the battle field more freely without getting pinned or damaged.
- Piercing. Represents the ability of a unit to pierce armor, if the value is higher than enemy's armor value, the unit makes more damage in combat.
- Initiative. Higher initiative speeds up the units ability to reinforce after a battle and perform battle planning.
- Entrenchment. Represents the ability of a unit to build defensive structures and entrench before an attack.
- Combat width. Represents the size of the fighting unit. In order to fit in battle, the unit needs to fit into the provided combat width of the battle field. Different unit types increase the designed with with different amount: For example, infantry and armored battalions use 2 width and artillery, anti-tank and anti-air battalions use 1 width. Support battalions do not increase the combat width of a division.
- Hardness. Represents how large proportion of the division is made up from units which are armored and protected. Unit with high hardness will suffer more hard attacks and fewer soft attacks. Unit with low hardness will suffer more soft attacks and fewer hard attacks.
- Attrition. Gives chance of equipment loss every day.
- Additionally Reconnaissance and Weight are listed as Misc stats in Unit Details screen. See Base stats above for explanation of these.
- Osobny artykuł: Combat tactics
Combat tactics are chosen in the beginning of combat and changed every 24 hours. Reconnaissance stat affects the selection of the combat tactic where higher stat increases the changes to counter the tactic chosen by the enemy.
Combat is resolved in one hour turns, where both the attacker and defender take turns in attacking the units on the other side. In the following we refer to as the "attacker" the side who is on the offensive and initiated the combat and as "defender" the side which was attacked. A specific attacking and defending unit then depends on the combat phase and can refer to unit on either side.
Combat width works a lot like in HOI3, but is now more detailed. Each division will have a combat width which will tell you how many divisions fit into the frontline for active fighting. The available width of the combat goes up the more directions you attack from, so tactical flanking is needed if you want to leverage a numerical advantage. Width is also affected by certain combat tactics. Base combat width is 80, where additional directions bring 40 extra per direction. The combat width of a division depends on how it has been designed.
Divisions that do not fit on the frontline at the start of combat end up in reserves and will have a chance to join every hour in as long as there is room. The chance to join is greatly affected by doctrine tech, or by having a signal company attached to the division, and is important if you want to be able to leverage a lot of units in a single location, because if the frontline fall your side is forced to retreat no matter what.
Soft attacks and Hard attacks give the number of attacks against a defending unit. The Hardnesss stat of the defending unit determines the proportion of soft and hard attacks the unit receives: For example, unit with 100% Hardness receives all Hard attacks and none of the Soft attacks and unit with 25% Hardness would receive 25% of the Hard attacks and 75% of the Soft attacks.
If the attacking unit has lower piercing value when compared to defenders armor value, only half of the attacks are used.
The number of attacks is compared to number of defenses of the defending unit before calculating the possible damage, see following section on Damage dealing.
The attacker's Breakthrough values are used to determine how many defenses each of the attackers' units has. This is compared to the defenders' units hard and soft attacks to evaluate damage done to the attackers' units.
The defender's Defense values are used to determine how many defenses each of the defenders' units has. This is compared to attackers' units hard and soft attacks to evaluate the damage done to the defenders' units.
Each attack has the potential to be a hit or miss, where hits would cause HP and organization damage to the enemy unit. After each attack, the defending unit removes one defense (if it has some left) and the actual chance to hit depends on if the defender has defenses left or not. The base chance to avoid hit when unit has defenses left is 90%. It the defending unit has exhausted all of its defenses, the chance to avoid hits drops to 60%.
The amount of possible damage done is random, where a "dice" is used to randomly choose the amount of damage done. For HP damage the size of the dice is 2 and for organization damage it is 4. The exact amount of damage done to strength and organization is calculated by multiplying the obtained random integers by modifiers before applying the damage to the units.
When armored units are in combat against soft targets (with lower piercing stat), the organization dice size is increased to 6 representing the ability of the armored unit to make more damage.
The damage done to unit's HP reduces the attack and defense stats.
The following factors modify the number of attacks and/or defenses a unit has in combat (list is not exhaustive):
- River crossing gives reduction of 30% or 60% on attacks depending on the river size
- Night penalty of 50% for attacks
- Attacking a fort penalty of 15%
- Encirclement penalty for defender 30%
- Commander skill, +10% per skill point for both attack and defense
- Planning bonus, the base maximum is +50% which is further affected by techs
- Air support
- Country bonus
- Combat tactics
- Penalty for exceeding combat width
- Decryption advantage
- Paradrop penalty
At the end of the combat, a check is made how much HP (Strength) damage the unit has taken and unit's equipment is reduced proportionally to the losses. Modifier EQUIPMENT_COMBAT_LOSS_FACTOR in defines.lua is used, and it is 70% by default.