This article may contain outdated information that is inaccurate for the current version of the game. It was last updated for Vanilla.
- This page deals with combat mechanics. For information on the recruitment and maintenance of armies see army. For the individual unit types see land units. For the state of war see Warfare.
Land warfare is the deployment and maneuvering of military assets against an enemy in most cases resulting in combat between opposing armies. In EU4 most combat is land-based and, while the naval aspect of war holds importance, losing the land war is usually tantamount to defeat in general. The art of land warfare is therefore of significant importance, and its complexities are discussed here as fully as possible.
- 1 Combat interface
- 2 Deployment
- 3 Combat sequence
- 4 Combat statistics
- 5 Terrain
- 6 Sieges
- 7 Mechanics of an army
- 8 Strategies and tactics
- 9 See also
- 10 References
EU3 introduced a complex combat simulation with over sixty different positions for units on each side, with units moving about and firing at their flanks, covering holes in the line, and with reserves entering combat. The combat system was not transparent to the player though, and gave the impression that the combat was just about numbers, modifiers and dice-rolls.
In EU4, there is still no player involvement inside combat, but the interface now displays more information, showing amongst other information which regiment is fighting which, and who is moving where.
- Main article: Army#Composition
To maximize the effectiveness of an army, a mixture of troop types is important.
Combat width determines how many units can actively participate in a battle at one time. At the beginning of the game, all countries start with a low base combat width. As military technology advances, a country's combat width increases, allowing them to use more soldiers effectively at once. Terrain impacts the width of combat rather dramatically, so a small army can hold up a large one if they get lucky and catch them in the mountains. The combat width used in a battle is the highest combat width of any of the participants. For every 1 combat width, 1 additional regiment will be placed in the front or back line if sufficient troops are available. The combat width can be increased through military technology; its base is 15. Terrain gives modifiers to the combat width for both sides as following:
- Plains, Grassland, Coastline, Desert: No Modifier
- Mountains: -50%
- Hills: -25%
- Marsh: -25%
- Jungle: -25%
- Forest: -20%
- Woods: -20%
Combat width technology levels:
- Base: 15
- Military Tech (2): +5
- Military Tech (5): +2
- Military Tech (6): +2
- Military Tech (8): +1
- Military Tech (11): +2
- Military Tech (14): +2
- Military Tech (16): +1
- Military Tech (18): +2
- Military Tech (20): +2
- Military Tech (22): +2
- Military Tech (24): +2
- Military Tech (26): +2
The game uses an undocumented algorithm to automatically deploy land units on the battlefield, on each row for each side of the battle. Through observation and controlled experiments, the community has suggested a theory that the game seems to follow, dependent on the rough size and composition of each army.[This section's factual information is debatable. See the discussion page for more information]
NB: The player plays no part in unit deployment.
For the smaller army
- If there is not enough infantry to fill the entire first row:
- Deploy all infantry in first row.
- Deploy as much cavalry at the sides of the first row.
- If there is space left in first row:
- Deploy all artillery in the first row.
- Deploy all remaining artillery in the second row.
- If there is no space left in first row:
- Deploy all artillery in the second row.
- If there is space left in first row:
- If space left in the second row, deploy all remaining cavalry in the second row, beginning with the positions behind the cavalry in the first row and then going inwards to the artillery.
- If there is enough infantry to fill the entire first row:
- Deploy all infantry in first row, except the outer positions in the amount of cavalry available but not more than 6[[this amount is made up]] (3 left and 3 right).
- Deploy up to 6 cavalry in first row at the sides of the infantry.
- Deploy all artillery in the second row.
- If space left in the second row, deploy all remaining infantry in the second row besides the artillery, but leave the outer positions in the amount of cavalry available but not more than 6[[this amount is made up]] (3 left and 3 right).
- Deploy all remaining cavalry in the available space in the second row, beginning with the positions behind the cavalry in the first row and then going inwards to the infantry.
For the bigger army
- Deploy as much infantry in the first row as are able to attack the enemies units in the first row, except the outer positions in the amount of cavalry available but not more than 6[[this amount is made up]] (3 left and 3 right).
- Deploy as much cavalry as are able to attack the enemy's regiments in the first row.
- Deploy all artillery in the second row.
- If space left in the second row, deploy as much infantry in the second row besides the artillery as there are positions available behind the infantry in the first row.
- If space left in the second row, deploy as much cavalry in the second row besides the infantry as there are positions available behind the cavalry in the first row.
When two warring armies meet in a province a battle will commence. A battle will last until one side is routed or annihilated.
Combat is divided into a series of 3-day phases. Phases alternate between Fire and Shock, with the Fire phase happening first.
Units in the front make an attack at enemies straight ahead of it. If no enemies can be found straight ahead, the unit will try to attack other enemies as maneuver (range) allows. Artillery also make an attack, even if they are in the back row. They only deal 50% damage, however. [Ambiguous: do artillery do 100% damage if they are in the first row? Or always only 50% regardless?]]
At the beginning of each phase, each side rolls a die. The result is used to determine the morale damage and casualties inflicted by that side during each of the three days of that phase.
The result is computed as following:
die result = die roll + max(attacking leader skill - defending leader skill, 0) + (attacking unit attack pips - defending unit defense pips) - terrain modifiers
- Die roll: A random number between 0-9, rolled for each entire side at the beginning of each phase (not each day).
- Leader skill: The leader skill for that phase (Fire or Shock). The more skilled leader gets a bonus to their attack equal to the difference in skill.
- Attacking unit attack pips: The attack pips for the attacking unit for the current phase, or Morale pips if computing morale damage. Note units on both sides attack during every phase---here "attack" does not refer to which army is attacking.
- Defending unit defense pips: The corresponding defense pips for the defending unit.
- Terrain modifiers: Harsh terrain, river crossings, and amphibious landings may give a penalty to the attacking army.
Note that, although all modifiers are shown in the same box, die rolls only affect the damage dealt for that side, whereas both sides' leader skills and the terrain modifier affects the damage dealt by both sides.
Casualties caused by each unit during each day are computed as follows:
casualties = base casualties * attacking unit strength * attacking unit modifier * (100% + attacking unit Combat Ability) * attacking unit Discipline / (defending unit Tactics * defending unit Discipline)
- Base casualties: Base casualties is determined by the die result according to the following table:
Die result -2 or less -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 or greater Base casualties 4 8 12 16 20 24 32 40 50 60 70 80 90 100 100 120
- Mean casualties for a particular attacker advantage (net modifier to the attacker die roll) are as follows. Marginal proportional increase is the ratio of that entry compared to the last.
Attacker advantage -11 or less -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 or greater Mean base casualties 4.0 4.4 5.2 6.4 8.0 10.0 12.8 16.4 21.0 26.6 33.2 40.4 48.2 56.6 64.6 74.2 83.0 91.0 98.0 104.0 109.0 113.0 116.0 118.0 120.0 Marginal proportional increase 0.0% 10.0% 18.2% 23.1% 25.0% 25.0% 28.0% 28.1% 28.0% 26.7% 24.8% 21.7% 19.3% 17.4% 14.1% 14.9% 11.9% 9.6% 7.7% 6.1% 4.8% 3.7% 2.7% 1.7% 1.7%
- Attacking unit strength: If the attacking unit has below its maximum of 1000 men, damage will be reduced proportionally.
- Attacking unit modifier: The attack modifier from the attacking unit's technology, e.g. "Infantry Fire".
- Attacking unit Combat Ability: Any Combat Ability bonuses the attacking unit has.
- Attacking unit Discipline: The Discipline of the attacking unit.
- Defending unit Tactics: The Tactics of the defending unit.
Comments in defines.lua imply that casualties also increase by 1% per day of combat. This is difficult to confirm, however.
morale damage = base casualties * 0.01 / 6 * attacking unit strength * attacking unit maximum morale * (100% + attacking unit Combat Ability) * attacking unit Discipline / (defending unit Tactics * defending unit Discipline)
- 6 base casualties translates to dealing 1% of the attacking unit's maximum morale as morale damage. Note that the modifiers may be different.
- Attacking unit maximum morale: Note that this is the maximum morale of the attacking unit, not the current morale.
|10% discipline||+10% * AND -10%||+20% * AND -20%|
|10% combat ability||+10%||+20%|
|10% infantry(etc) shock(fire) multiplier||+10%||+10%|
|10% max morale||+0%||+10%|
|1 unit pip advantage||+20%||+20%|
|1 terrain disadvantage||-20%||-20%|
|1 general pip advantage||+20%||+20%|
- as of 1.6 discipline is multiplied by tactics defensively.
Military tactics reduces the amount of damage your troops take in combat. Military tactics is increased by Military Technology.
- Base: 0.50
- Military Tech (4): +0.25
- Military Tech (6): +0.25
- Military Tech (7): +0.25
- Military Tech (8): +0.25
- Military Tech (12): +0.25
- Military Tech (15): +0.50
- Military Tech (19): +0.50
- Military Tech (23): +0.50
- Military Tech (30): +0.50
Each military unit has two stats in four categories: Fire, Shock, Morale, and Maneuvers. The first set of pips are yellow for offensive, and the second set of pips are green for defensive. With the exception of Morale, every combat phase the offensive/defensive pips are used against each other to calculate the number of casualties/survivors of each combat phase. Morale's pips are used to state the rate that morale will decrease as combat ensues.
Morale is an important factor in fighting battles. Each turn of combat a unit will take a Morale hit. Once an army's average Morale value has been reduced to zero the army will attempt to retreat. Retreat cannot happen until both a fire and a shock phase have completed, so an army that has its morale reduced to 0 before that point will be destroyed.
An army that has its average morale drop to 0.5 or lower is flagged as disorganized, which is indicated by a small lock icon next to its morale bar on the map and interface. A disorganized army is unable to start moving until its morale has recovered to a certain point.
If an army loses a battle while having low enough morale to be disorganized, they will be forced to retreat to a safer province often much further away than just one over – it could be several provinces from where the battle was fought. They will usually retreat to one with a high base tax value, forts, and no adjacent enemies. While retreating, it cannot be engaged in combat or be controlled until it reaches the safer province, nor will it reinforce its losses or incur extra reinforcement maintenance. The army will also move 50% faster, and will recover morale at a normal rate during the retreat.
After every battle is fought an army must spend some time not fighting for its morale to recover.
- A shattered army will get an extra morale bonus as it stops retreating.
- Morale is not gained while forced marching
The following contributes to the maximum morale of a nation's army.
- Army Maintenance: Ranging from 20% at minimum maintenance (minimum of 0.51) to 100% at maximum maintenance (multiplicative modifier)
- Defensive idea group: +15%
- Plutocratic idea group: +10%
- Certain unique national ideas
- Researching military technology:
- Military technology (0): +2.0
- Military technology (3): +0.5
- Military technology (4): +0.5
- Military technology (15): +1.0
- Military technology (26): +1.0
- Military technology (30): +1.0
- Bankruptcy: -1.0
- Prestige: +20% at 100 Prestige, -20% at -100 Prestige
- Army reformer advisor: +10%
- Army tradition: +25% at 100 tradition
- Being the Defender of the Faith: +10%
- Piety (Muslim only): +25% at 100% Piety
- War exhaustion: -2% per 1 war exhaustion
- Various events, decisions, and modifiers
Every month, a regiment recovers a 15% of its maximum morale. The following contributes to a nation's morale recovery speed.
- Regiment is in home territory: +5%
- Army tradition: +10% at 100 tradition
- Certain unique national ideas
- Various events, decisions, and modifiers
The old Combined Arms bonus that used to give +25% bonus damage in EU3 has been removed. It is now called Insufficient Support and is now a penalty. Each Technology Group has a limit of what is an effective ratio of Infantry to Cavalry. If your ratio of Cavalry to ( Infantry + Cavalry ) is too high, your military tactics are reduced by 25%, causing you to take more damage. The ratio is checked in mid-battle.
Cavalry/Infantry ratios per tech group:
- The tooltip states that "Your army can contain up to x% cavalry" before getting the penalty, which differs from "Your number of cavalry units must not exceed x% of your infantry units". Especially for nomad tech countries this makes a huge difference, as 100% of your army size means you can build an army without any infantry, without getting the penalty.
A unit’s effective range is determined by its Maneuver value and its strength. A unit that has 75% or more of its troop strength, they will fight at full range, if between 50 and 75%, they will fight at 50% maneuver range, and between 25% and 50% strength they will fight at 25% of their maneuver range. This is always rounded down, but can't be zero. There are technologies which increase your units’ range as the game progresses.
|Please help improve this article or section by expanding it. Further information might be found on the talk page.|
When armies meet in a province the game selects a terrain that lasts for the duration of the battle - plains or mountains, for example. An important parameter in the selection of terrain is the list of terrain percentages that each province has (and which can be viewed on the terrain map mode by hovering over a province). Another parameter is the manoeuver value of the attacking and defending generals; a developer has exaplined that: "the defender will try to select the one with highest defense bonus, the attacker the one with least defense bonus." How the game calculates this selection is not fully understood and it seems that the randomness of the selection can be overpowered in certain situations (with generals that have a high maneouver value for example).
Note that, contrary to the tooltip on uncolonized provinces, terrain has no effect on supply limit.
- Crossing a river gives a -1 penalty to the attacker.
- An amphibious landing (attacking from sea or landing directly with ships) give a -2 penalty to the attacker.
When your troops enter an enemy province and are not moving into another province, a siege will begin. To progress in a siege, you need at least as many besieging troops as the enemy garrison. It does not matter which unit type the besieging units are, but only infantry can try to storm the enemy fortress. Progress in a siege will never decrease as long as attackers are continuously present; however, if all attackers leave, it will be instantly reset.
Besieging army also have 1% to base attrition.
The defensiveness of a province affects how long each siege phase will take, effectively determining the duration of the entire siege. This can lead to situations where one country can siege multiple provinces, while its enemy only manages to siege one or none. Therefore winning a "siege race" is all about having as high defensiveness as possible. Local defensiveness is an additional bonus that is only applied to a particular province, not the entire country. Defensiveness is affected by the following:
- Various events, decisions, and modifiers
- +10% at 100 power projection
- +25% by Military Engineer advisor
- Additional local defensiveness
- +10% Town hall (4th Government)
- +200% March (Unique, only in a border province)
- Various events, decisions, and modifiers
Siege ability acts as a counter to an enemy's defensiveness, decreasing the siege phase length when the player sieges a province. It is affected by the following:
|—||Offensive Ideas 5: Engineer Corps||—||—|
|—||Dutch Ideas 6: Army Sappers
Timurid Ideas 4: Unleash the Tiger
|—||Defensive-Offensive: The Sappers Act|
|—||—||—||Innovative-Quality: Modern Firearm Techniques|
- Various events, decisions, and modifiers
- +5% at 100 army tradition
- +5% for Hindu countries who choose Shakti as patron deity
A siege progresses in phases. Each phase has a base length of 30 days, modified by the defender's Fort Defense ("defensiveness" in the game files) and the attackers Siege Ability. Military Tactics also affects the duration, modifying by roughly 6.24% per 0.25 difference; reduction if attacker has higher, increase if defender has more.
The mean number of phases to finish a siege for a particular starting bonus is as follows:
|Starting success %||-100.00%||-92.86%||-85.71%||-78.57%||-71.43%||-64.29%||-57.14%||-50.00%||-42.86%||-35.71%||-28.57%||-21.43%||-14.29%||-7.14%||0.00%||7.14%||14.29%||21.43%||28.57%||35.71%|
|Sieges per year||0.28||0.40||0.48||0.57||0.70||0.82||0.96||1.12||1.29||1.48||1.68||1.88||2.10||2.37||2.69||3.15||3.72||4.32||4.95||5.60|
"Sieges per year" is computed at the default phase length of 30 days.
At the end of each siege phase, a die (1 to 14) is rolled. The following modifiers are then applied:
- Siege status. The most important modifier. As the siege goes on, this bonus will increase from its starting value of 0 to a maximum of 12 depending on previous die rolls.
- Leader siege. If the attacking army has a leader, the leader's siege skill is added as a bonus.
- Leaders can have Siege, capped at 6. Getting the maximum Siege 6 with no leader Siege bonuses is possible, but the chance seems to be less than one in a thousand.
- The Inside Man event can increase leader siege by 1.
- The Engineer Corps idea (Defensive Ideas) increases leader siege by 1.
- The Army Sappers unique Idea (Netherlands) increases leader siege by 1.
- Artillery. A bonus depending on the ratio of their Artillery to the defender's Fort Level:
Modifier Artillery per Fort Level +1 Any artillery at all +2 At least 2 artillery per fort level +3 At least 3 artillery per fort level +4 At least 4 artillery per fort level +5 At least 5 artillery per fort level
- Blockade. If the province is coastal and not blockaded, a -1 penalty is applied, with an additional -1 if the defender owns the province (?)
- Fort Level. The defender's Fort Level is applied as a penalty.
- Walls Breached. A +3 bonus is applied if the defender's walls have been breached. It happens when 14 is rolled on the dice.
The highest possible starting bonus is thus +6 for the leader, +5 for artillery, and -1 for Fort Level 1 for a total of +10.
The die roll may result in an increase of the siege status, to a maximum of 12. This improves the results of future siege stages.
|5 - 11||Supplies Shortage||+1 siege status|
|12 - 13||Food Shortage||+2 siege status|
|14 - 15||Water Shortage||+3 siege status|
|16 - 19||Defenders Desert||+1 siege status, reduces garrison (?)|
|20 or more||Surrender||Siege successful|
Additionally, if a 14 is rolled on the die (before modifiers), the defender's walls are breached. This applies a +3 bonus to future rolls. Walls cannot be breached more than once.
Therefore, the attacker needs at least a net +6 bonus to have a chance of ending the siege. Since siege status and Walls Breached will eventually reach their combined maximum of a +15 bonus and the maximum Fort Level is 9, only non-blockaded coastal sieges can possibly fail to eventually succeed.
The attacker may choose to storm the garrison with their infantry. This results in a speedy conclusion of the siege at the cost of 5 Military power, and usually lots of lives. The attacker loses roughly 10 times as many men as the garrison if the walls are not breached and 1.5 times as many if they are [(what else affects this?)]. Only infantry can assault.
The assault will end upon either the fall of the fort, the loss of attackers morale or one sides soldiers being entirely killed. Loss of the attacker's morale would mean the siege continues, the attacker free to stay in the province and recover morale, unlike in a field battle.
Mechanics of an army
- Main article: Army
These conditions involve an army stack without directly requiring input from the player.
Low morale or retreat
See Land warfare#Morale.
Revolt risk reduction
A friendly army in a province will reduce the revolt risk proportionately to the size of the army. Each unit composing the army gives a -0.25% bonus to revolt risk.
When an army is exiled, a black flag will be visible over it. Any regiments in this exiled army are unable to participate in combat, siege provinces or explore. They must first return to a province controlled or owned by their nation, or board a transport ship, to reset; entering the territory of a vassal does not clear the exile status. Troops in exile are able to march through territory of countries you do not normally have military access to - they have 'diplomatic immunity'.
Exile occurs in two different circumstances and serves different purposes in the game:
1) when a war ends, any armies still in territory they don't have peacetime access to are exiled. This prevents armies from being permanently stuck in places they can't get out of, as well as several exploits.
2) when a war begins, any armies in provinces their nation only has military access to are exiled. This prevents advance placement of troops outside one's territory in preparation for war.
An enemy's provinces can be looted marching an army of any size through them. The owner of the looting army will gain money directly into their treasury equal to the base tax of the province being looted. This amount is doubled for hordes.
A province is "lootable" if it is all of the following:
- The looter has no core on this province
- Is an enemy owned and enemy controlled territory
- Does not have the "looted" modifier (which lasts for 6 months)
- The province does not border any province where the looter has military access (allies, agreements, a province occupied by the looter or an ally).
Exiled armies and moving armies can not loot. In order to loot multiple provinces in quick succession, it is necessary to stop the army in each province and momentarily begin a siege before moving on to the next province.
These actions are available from an army's information panel.
Attach to army
This action attaches your army to an allied country's army, causing your army to travel and fight alongside the ally's army without further input from the player. The general with the highest ability scores will command the armies in battle. The army can be detached at any time except in battle.[Verification needed] An attached army cannot board transports.
The native population of a non-city province can be reduced using the Attack Natives military action, but this action costs military monarch power and permanently reduces the potential value of the province. See Colonization.
Clicking the hunt rebels icon in a selected army panel will set the army to automatically travel to and fight rebel armies that appear in its surroundings. The army will then return to its previous position. Armies that are ordered to move will stop hunting rebels. An army will not hunt rebel armies that are larger than it is.
Strategies and tactics
- Defending territory is easier than conquering it, and the smaller the battlefield is the easier it is to hold.
- Your enemies want to besiege and conquer your provinces.
- The more the border is fortified, the better. Higher level forts means longer-lasting sieges, more men needed to assault/siege and more attrition.
- If the border is narrow (1/2 provinces) a March might be worth building. March, Severe Winter and Scorched Earth can cause an outstanding attrition (see Attrition on land) that can easily burn the enemy manpower pool, especially if the province demands a long travel time to adjacent provinces, if the province has a low base tax (and corresponding low supply limit), and if the province has high defensiveness and a large fort.
- Sometimes an enemy will also use hunter-killer armies to destroy your armies and protect its sieges.
- Disturbing the enemy's siege will reset the siege timer. Even though damage dealt will still stay, the siege timer is the main factor in winning a siege.
- If your main army is bigger than the enemy's hunter army, destroy that army and then hunt the siege armies. Most of them will flee, but you can often catch them.
- If your forces are inferior to your enemy's hunter army, evade that army and focus on killing siege armies. This will force the enemy to split up its forces to replace the siege armies.
- If the enemy is concentrating its forces in one province or in a few neighboring ones, attacking the massed force can be dangerous.
- But for as long as the enemy ties its forces to specific provinces, those forces will not be able to respond to a mobile threat.
- Besiege the enemy's land instead, while spreading out your forces. Starting with comparable forces, the side that more widely disperses its armies will be able to besiege and loot more provinces than the side that concentrates its forces.
- If the enemy sends troops while continuing its siege, destroy this army rather than continuing your siege.
- If the forces the enemy sends are too big to be destroyed, evade them and attack the siege armies instead.
- Use Scorched Earth on your territories. This effect lasts for 5 years and increases attrition in a province at the cost of reducing tax income.
- Scorched Earth reduces Tax efficiency in the province by -50%. The penalty is the equivalent of the province's being blockaded.
- Scorched Earth reduces Goods produced in the province by -0.33.
- Scorched Earth reduces the supply limit modifier of the province by -50%.
- Scorched Earth increases the defensiveness of the province by +25%.
- Try to control your enemy's movement and lure the enemy into these scorched provinces.
Standing or situational army
- A standing army contains a number of troops with this number only changing slightly, usually being near the force limit.
- A standing army has the advantage of a military deterrence. Nations which can field fewer troops than this army will be much less likely to attack.
- Even though the number of troops is not the only point of accessible reference for warfare capabilities, it's the most obvious.
- Even when kept at low morale, with low land maintenance spending, a standing army will be battle ready much faster than troops which have to be recruited first.
- If revolt risk is high and rebels are spawning continually, a standing army will most likely be cheaper than recruiting and disbanding troops repeatedly.
- Recruiting regular troops costs manpower. After the standing army is created, the manpower reserve can refill.
- A situational army contains only small numbers of troops, and will recruit additional regiments when needed.
- Maintenance for nonexistent regiments is even lower, 0 each month, than for standing regiments with the minimum funding.
- Hostile nations will possibly misjudge the military capabilities, thus could be baited into a war they can not win.
- With Administrative ideas and Innovative ideas, mercenaries are cheap enough to be competitive in cost with regular troops. Mercenaries' faster recruiting time and independence from manpower make them ideal troops for the situational army strategy.
Assessing the enemies' strength
Correctly assessing the enemy's capability for warfare is essential for good preparation. There are multiple indicators which allow its estimation:
- Number of troops. The most direct indicator of a nation's strength is the number of enlisted troops. Information on a country's enlisted troops is available through the Ledger page on armies.
- Manpower. Arguably the most important indicator of a country's military readiness is its manpower reserve. A powerful military nation might have its manpower depleted after a costly war, and a lower manpower indicates a more fragile military that is not able to replenish losses. Information on a country's manpower is available through the Ledger page on armies.
- Number of ships. The number and type of ships determines whether a country will be able to blockade its opponent, or prevent a blockade. Information on a country's navy is available through the Ledger page on navies.
- Military technology. The military technology level of a nation determines what troops it has available, as well as its combat modifiers. Information on a country's technology is available on the Diplomacy panel of a country, or in the Ledger.
- Military leaders. Good generals and admirals can affect the outcome of battles and reduce losses. Information on a country's military leaders is available through the Ledger page on leaders.
- Location of troops. Troops are not able to fight where they don't exist. A powerful navy can't blockade a country unless it can project and maintain its presence at the target, and a powerful army can't fight a distant country without naval transports or lots of military passage agreements.
- Other conflicts. Contemporaneous wars with other nations can limit a country's strength.
- Internal revolts. Rebel-held provinces severely diminish a country's enthusiasm for war.
- Tech group. Usually Western troops are superior to those of other tech groups. See Land units.
- Idea groups. A country's ideas, if focused towards the Army or Navy, can benefit its combat. Also, many nations have ideas boosting their troops (France, Ottoman Empire and so on).
For fastest sieging:
- Bring lots of artillery if finances permit, optimally 5 per level of fort.
- Siege as many provinces as is safe to do so ("carpet sieging").
- Distribute one artillery to each province being sieged---one artillery will give a +1 bonus regardless of fort Level.
- If any artillery is left over, concentrate it with the best siege leader---in terms of successful sieges per length of time, each point of bonus is worth more than the last.
- Use a small portion of your army to lure the enemy into attacking it, then come in with your main army and crush the enemy. Make sure that your bait army can withstand the enemy's attack until your main army can arrive.
- Pay attention to the terrain. While river crossings are often only a minor inconvenience, a much lower combat width due to mountains or forests can greatly reduce the numeric advantage of the larger army.
- Use leaders. Even a bad one is better than no leader.
- As long as you are in allied territory, you can instantaneously move your leader from army to army as long as neither is in combat. This way you can use one good leader to fight many battles, saving you military monarch points.
- Armies sometimes retreat with very low morale, and in giving chase the pursuer can sometimes annihilate the enemy before the demoralized army can recover morale and numbers. However, it is possible to overcommit an army in pursuit, putting it in a disadvantageous position.
- Attrition is deadly - your manpower is an important constraint. Avoid losing manpower unnecessarily. A 10,000-man army with 5% attrition will increase the demand on your manpower by 500 men each month. The actual amount of manpower lost depends on the rate of reinforcement to the armies in the field.
- During a war, you will increase your military tradition by fighting battles and such. In peacetime, it will decay. Since the skill of your generals depends on army tradition -- and greatly impacts the outcome of battles -- consider buying a few generals with military monarch points at the end of a major conflict, rather than at the start of the next one.