Jump to Combat Strength Modifications

Basics[edit | edit source]

A unit can't enter a tile occupied by an enemy unit. Instead, it will ask if you want to attack. Combat usually locks units in battle until one is destroyed. An attack costs the aggressor one move-point. It will also lose moves proportional to damage it suffers. Attacking a tile does not move there — the surviving unit remains where it was.

Some combat rules are obvious—units must have nonzero attack strength to attack. Defenders with zero defense lose immediately. There are limits on which units can attack which others. Most Land units can only attack other Land units. Most ships can attack other ships and also Land units. Helicopters and Marines can attack Land and Sea units and can be attacked by most units. Bombers and Missiles can attack any Land or Sea unit. Fighters and Anti-Aircraft Artillery can attack almost all units.

Fighters in a city or a Base can be attacked by land. Ships in port cities suffer defense penalties. Marines and Anti-Aircraft Artillery can attack targets from aboard ship or Helicopter; other Land units must disembark and wait one turn before engaging enemy units (unless the ship first docks inside a native or allied city, or default game settings were changed. /show universal_unload and u)

A unit ordered to Sentry remains in place indefinitely and no longer asks for orders each turn. Sentried units can be reactivated manually by selecting them, or activate automatically if an enemy unit comes into view (or if they have finished healing.) Land units can be ordered to Fortify, which spends a fractional move-point preparing to be attacked. Once fortified they enjoy the same +50% advantage as land units in a city. A unit with no remaining moves can't fortify—it needs remaining move-points to start the next turn fortified.

Spies in combat. Spies can harm enemy units by doing sabotage.

Combat Mechanics[edit | edit source]

Each unit begins combat with one or more hitpoints—the amount of damage it can sustain. (See Units for stats on each unit type.) Combat consists of successive rounds of violence between the units, which cannot be interrupted and ceases only when a unit dies by reaching zero hitpoints. (The exception is most ancient sea units—they can attack for a maximum of 15 combat rounds.) In each combat round, only one unit succeeds in wounding the other. The damage a unit inflicts with each blow is called its firepower.

In each combat round, which unit inflicts damage is based on probability. The attacker's chance is relative to its attack strength, while the defender's chance is relative to its defense strength. For example, on an open field with no other bonuses: Archers have attack strength 3 and attack a Phalanx with defense strength 2. For each round, the Archers will have odds of inflicting damage, while the phalanx has odds.

Tired attack. When units attack with less than one full move-point, they are penalized because of tiredness. Only a fraction of their attack strength is used. If they have move-points, they will attack with strength. If they have move-points, they will attack with strength, and so on.

There are other factors which affect combat strength. These are summarized in the tables below:

Combat Strength Modifications[edit | edit source]

Veteran Bonus
Unit is not veteran ("green") ×1.00
Unit is veteran 1st level ("veteran") ×1.50 V1.png
Unit is veteran 2nd level ("hardened") ×1.75 V2.png
Unit is veteran 3rd level ("elite") ×2.00 V3.png
Unit is veteran 4th level (elite-2, "crack") ×2.10 V4.png
Unit is veteran 5th level (elite-3, "master") ×2.20 V5.png
Unit is veteran 6th level (elite-4, "champion") ×2.30 V6.png
Combat Strength Modifications
Terrain Multiplier defense bonus, TM × TM
Terrain includes a river ×1.33
Phalanx or Pikemen attacking and attacker owns the Agōgē of Sparta ×1.5
In city with SAM battery against most Air units (not Stealth)... ×2
.... In city with SAM battery against Stealth Air units ×1.25
In city with SDI defense against Missile ×2
In city with Coastal Defense against Sea units ×2
In city with Fortifications (no Walls) vs. Land unit (not Howitzer) ×1.75
In city with City Walls against Land unit (not Howitzer) ×3
Land unit/Fighter/Helicopter in Fort against Land or Sea units (not Armor) ×1.33
Non-Sea unit in Naval Base -- **same as Fortress (below) **
Fighter in Fortress against Land or Sea units (except Armor) ×1.33
Land unit/Heli in Fortress against Land or Sea units (except below...) ×2
... Land unit in Fortress against Armor I, Helicopter, or Air units ×1.66
Sea unit in Naval Base. ×1.33
Land unit fortified or in city ** ×1.5

These factors are combined: Each factor that qualifies as true is multiplied into the final bonus.

** Land units able to fortify get a 1.5x "automatic fortified" bonus in a city, regardless if fortified or not.

The Base bonus page gives a chart for the bases above. Also see: Terrain bonuses and base bonuses.

There are more circumstances that result in adjustments to combat:

Special Combat Modifications
Pikemen defends against mounted units (except Cavalry) Defense strength ×2
AEGIS Cruiser defends against Aircraft, Missile or Helicopter Defense strength ×3
Missile Destroyer defends against Aircraft, Missile or Helicopter Defense strength ×2
AAA or Mobile SAM attacks or defends vs Aircraft or Helicopter Strength ×2
Armor II defends against Missile Defense strength ×2
Stealth Aircraft attacks against units with Anti-Air bonus Attack strength ×1.25
Fighter attacks a Helicopter Helicopter firepower reduced to 1

Helicopter defense strength ×½

Ship defends while inside city: "Pearl Harbor Effect" Attacker firepower ×2

Ship firepower reduced to 1

Sea unit attacks Land unit Both have firepower reduced to 1
Sea unit defends against Marines Defense strength ×2
Cruiser,Battleship,Missile Destroyer,Aegis Cruiser defend vs Submarine Defense strength ×2
Destroyer defends against Submarine Defense strength ×4
Knights defend against mounted units (except Cavalry) Base Defense strength = 3
Knights defend against any foot soldiers Base Defense strength = 2

Promotions[edit | edit source]

General Promotions. Most units have a chance to gain a higher veteran level when they survive combat. This gives veteran bonuses to their Combat Strength. Crack V4 units also gain + move-point over standard. With two exceptions, all combat units have the following chances of promotion:

Land and Sea Units: Veteran Promotion Chances
V0→V1 (Green to Veteran) 50% V1.png
V1→V2 (Veteran to Hardened) 33% V2.png
V2→V3 (Hardened to Elite) 20% V3.png
V3→V4 (Elite to Crack) 15% V4.png
V4→V5 (Crack to Master) 15% V5.png
V5→V6 (Master to Champion) 15% V6.png

Air Promotions. Offensive Air units' promotions are slightly lower, to balance getting more attacks per turn:

Air Units: Veteran Promotion Chances
V0 (Green to Veteran) 40% V1.png
V1 (Veteran to Hardened) 25% V2.png
V2 (Hardened to Elite) 16% V3.png
V3 (Elite to Crack) 10% V4.png
V4 (Crack to Ace) 10% V5.png
V5 (Ace to Top Gun) 10% V6.png

Marines' promotion rates represent foot soldiers' upgrades to modern weaponry as the game progresses:

Marines: Veteran Promotion Chances
V0 (Green to Veteran) 60% V1.png
V1 (Veteran to Hardened) 50% V2.png
V2 (Hardened to Ranger) 40% V3.png
V3 (Ranger to Commando) 30% V4.png
V4 (Commando to Green Beret) 20% V5.png
V5 (Green Beret to Navy SEAL) 15% V6.png

Marines' veteran bonuses represent improved strength of weapons and special ops forces in the late game:

Veteran Combat Strength Multiples
V0 (Green) 100%
V1 (Veteran) 150% V1.png
V2 (Hardened) 175% V2.png
V3 (Ranger) 250% V3.png
V4 (Commando) 300% V4.png
V5 (Green Beret) 350% V5.png
V6 (Navy SEAL) 400% V6.png

Note: 1. Marines are the last strong foot unit, yet come in the middle of the tech tree. Rather than upgrade to a newer unit, the game represents the need for experience and training for modern special ops. 2. A veteran Marine usually needs 5 battles to become Ranger, where it can defend slightly better than older cheaper faster Alpine Troops. 3. A veteran Marine requires 20 successful battles on average to become Navy SEAL, a rare unit attacking at 89% the strength of a green Howitzer. 4. Thus, the late bonuses serve to slightly mitigate the rapid uselessness that occurs for late-game foot units; and provide a role for multipurpose special ops in modern warfare.

Injured Movement[edit | edit source]

Damaged Land and Sea units begin each turn with fewer move-points than normal. Their move-points will be proportional to (current_hitpoints / total_hitpoints). However, each unit class is guaranteed a minimum amount of moves: this is referred to as min_speed. Land units have a min_speed of 1. Ships made from wood have a min_speed of 2. Modern metallic ships have a min_speed of 3. Aircraft suffer no min_speed losses and always keep 100% of their move points.

Healing[edit | edit source]

Damaged units enter combat at a disadvantage. To regain hitpoints they must spend turns neither moving nor attacking. They regain health each turn according to the table below:

Healing Factor Modifications
Resting unmoved +10%
Fortified *additional +10%
In a City +33%
Unit is a Ship (see chart below) +8%
Fortress: Land or Helicopter unit. +25%
Fort: Land units only. +10%
Airbase: Aircraft . +15%
Airbase: Helicopters . +25%
Land unit in city with Barracks Completely restored
Sea unit in city with Port Facility Completely restored
Air/Helicopter unit in Airport city. Completely restored
  • A fortified unit gets +10% for resting unmoved and +10% for being fortified, for a total of +20%.
  • If you sentry a damaged unit, it will become active and request new orders after its hit points are fully restored.

Crew repairs heal ships 8% every Turn Change regardless of whether the unit has moved.

Crew Repair
Ship type Repair rate
10hp 0hp
20hp 1hp
30hp 2hp
40hp 3hp

You may produce new V1-Veteran units in a city if it has the appropriate building for its type:

B.barracks i.png Barracks cost:30 upkeep:1 requires:None

Makes veteran Land units

B.barracks ii.png Barracks II cost:35 upkeep:1 requires:Gunpowder

Makes veteran Land units

B.barracks iii.png Barracks III cost:40 upkeep:1 requires:Mobile Warfare

Makes veteran Land units

B.port facility.png Port Facility cost:60 upkeep:3 requires:Amphibious Warfare

Makes veteran Sea units

B.airport.png Airport cost:120 upkeep:3 requires:Radio

Makes veteran Air and Missile units

*Marines made in a city with Barracks III, Port Facility, AND Airport come out V2. Sun Tzu's War Academy gives an additional +1 veteran level to Land units. Magellan's Expedition gives an additional +1 veteran level to Sea units.

Stack-Kill, Stack-Escape; Cities, Forts, Fortresses[edit | edit source]

One unit defends a stack. [edit | edit source]

When several units on the same tile are attacked, the unit most capable of defense protects the entire tile.

  • More precisely, for all defenders on the tile which can defend against the attacker, winning chance is calculated to the precision of 0,001­%, and the best result is chosen to defend the whole stack. If several units have similar results, the cheapest unit defends first.

Stack-Kill[edit | edit source]

If defenders are inside a City or Base, a lost battle only kills one defending unit. Otherwise, loss of the defender results in Stack-Kill: the loss of every attackable unit on the tile.

When a unit transporting other units is in combat, only the attacking unit participates in the engagement, and its passengers are lost if it loses.

Stack-Escape[edit | edit source]

Air and Sea units (from Galleon onward) can sometimes survive a Stack-Kill event. When they are present in a stack whose defender has died, each has a separate 50% chance to escape to an adjacent tile if and only if it has at least 1 more remaining move point than the attacker. For example, if an attacker with 2 remaining move points kills the defender of a stack, each defending unit in that stack needs 3 or more remaining move points to qualify for a chance to escape. (The act of escaping expends 1 move point.)

Stack-Escape simulates the ability of Air and Sea units to escape in multiple directions if "faster" than the attacker, and provides superior playability and realism in their ability to escort each other.

City Population Loss.[edit | edit source]

When a City with no walls loses a unit, one citizen is lost if the attacker was a Land unit1,2. Once the last defender is gone, you may conquer the city with a Land unit or Helicopter. Ships and aircraft can attack cities but not capture them. A captured City loses 1 population, which destroys a City if it is size 1. Upon capture of a City, each building has a 20% chance of being destroyed. The victor may steal a technology from the former owner.

1Knights cause population loss only during city capture, not when killing units inside the city.

2The server setting killcitizen_pct regulates the chance of one citizen being lost, and defaults to 60% starting with MP2-Brava 1.2


Forts, Fortresses, Castles, and Bunkers[edit | edit source]

Building a Fort requires Masonry. A Fortress requires an existing Fort and Construction tech. To build one of these, move Settlers, Workers, Legions, Engineers, or Proletarians to a tile and give the order. A Fort or Fortress can go anywhere except on a city-center or in water. More information is available by clicking the link for each base type. Castles and Bunkers are types of modified Fortresses that are built over top of them, and take a significant amount of work to finish. They defend the same, but enemies cannot see units inside. Castles are immune to attacks from Siege Rams and Bunkers are immune to attacks for Air and Missile units.

Other Bases[edit | edit source]

There are three other kinds of military base. More info can be found on Airbases and Naval Bases by clicking the link for each base type. The last type of base is the Hideout:

  • A Hideout can be made in Forests, Swamps, Mountains, and Jungle, but not in someone else’s territory. Units in a hideout are invisible to other players. Only Foot soldiers can make Hideouts. All Land units and Helicopters can hide in them. Other types will be seen. Hideouts are not seen or detected on the map, are invisible to anyone not occupying the tile, and only appear as an activity icon near the unit who is hiding in it. The only way to see a Hideout is to have a unit inside it. Hideouts can't co-exist with other base types. Hideouts utilize natural terrain and foliage; therefore, for each turn it is unoccupied, a Hideout has a 15% chance of being lost to weather or other forces of nature. Hideouts provide no bonus except for invisibility.

Vigil[edit | edit source]

Fighter types can Vigil - this orders them to auto-attack adjacent units if:

  • The other unit is an airplane type, Paratrooper, or Transport Helicopter.
  • The Fighter has better odds to win by attacking instead of defending
  • The Fighter is not the only unit defending a city
  • The Fighter has been ordered to Vigil
  • The Fighter has not moved more than its move limit for allowing Vigil:

Fighters on Carriers can Vigil until the Carrier moves. After Carrier movement, the Vigil order must be reset.

Pearl Harbor Effect[edit | edit source]

MP2 and most other rulesets have The Pearl Harbor Effect. If attacked in a city, defender firepower for Sea units is set to 1, and firepower of the attacker is doubled.

City Defenses[edit | edit source]

There are five buildings which improve the strength of units who are attacked inside the city:

City Defense Improvements
Fortifications.png Fortifications

cost:35 upkeep:0 requires:Construction 3x defense vs Land attacks

B.city walls.png City Walls

cost:65 or 75 upkeep:0 requires:Construction 3x defense vs Land attacks

B.coastal defense.png Coastal Defense

cost:65 upkeep:2 requires:Gunpowder 2x defense vs Sea attacks

Sam battery.png SAM Battery

cost:80 upkeep:2 requires:Rocketry 2x defense vs Aircraft (not Missiles)

B.sdi defense.png SDI Defense

cost:140 upkeep:4 requires:Laser 2x defense vs Missiles, "Nuke proof"

Note: the Great Wall wonder counts as City Walls. Gibraltar Fortress improves Coastal Defense.

Nuclear Combat[edit | edit source]

Nuclear bombs and missiles do not engage in combat like other units — they either strike a ground zero within range of an SDI Defense and are harmlessly destroyed, or detonate at a ground zero outside the range of SDI, which results in a blast area around the attacked tile. SDI only prevents detonation within its range of protection, but provides no protection from blasts after a nuclear device successfully detonated! Within the blast radius for the specific type of nuke, all units are destroyed. cities lose population, and each land tile has a 50% chance of becoming polluted with Fallout.

Fallout raises the chances of Nuclear Winter — terrain begins changing into desert, tundra, and arctic. Workers and Engineers must be given the clean fallout command to dispose of nuclear waste.

Diplomatic Combat[edit | edit source]

See this section in the page on Diplomacy.

Special Unit Attacks[edit | edit source]

Archers. Archers may do a Ranged Attack, which shoots arrows at all units on a tile, but for only one round of combat. The units who are successfully hit will lose 1 hitpoint each. The Archer and the units who failed to be hit are unaffected. The Archer loses all move-points after the Ranged Attack. This represents an historical advantage of Archers over mêlée units (hand-combat). Ranged Attack can't be done on cities and fortresses. ⇨ After Gunpowder, all units possess ranged weapons--already factored into their combat stats. Post-gunpowder, there is no case of ranged units vs hand-combat units. Therefore, the Ranged Attack mechanic is only used to represent bow+arrow vs hand weapons. This enables ancient tactics.

Zealots. Under Theocracy, holy warriors in their homeland have the skills and motivation to arrange ambushes, traps, skirmish assaults, explosions, and similar degrading attacks on occupational invaders. This uses the same mechanic as for Archers, and is represented by 3 combat rounds against up to 4 enemy units on the targeted tile.

Capturing Units[edit | edit source]

The following non-military units may be captured, which converts them into your own units:

  • Workers
  • Peasants, Pilgrims, Proletarians
  • Explorer
  • Caravan, Wagon, Goods, Truck

To capture a unit requires a foot soldier or mounted unit whose raw attack value is 3 or higher. (If less than 3, the units feel a decent chance to defend themselves and will fight for their freedom.) Units on a tile with other units may not be captured. Units in Forts, Fortresses, or Mountains may not be captured.

In longturn games, an idle nation's unit can't be captured unless inside the capturer's territory.

Expelling Units[edit | edit source]

The following non-military units can be expelled from your nation, which sends them back to their home country:

  • Settlers, Well-Digger, Workers, Engineers
  • Peasants, Pilgrims, Proletarians
  • Diplomat, Spy
  • Caravan, Truck
  • Explorer, AWACS

Expelling is easier than capturing. To expel a Land unit requires any Land-based military unit except Warriors. Units on Mountains terrain may not be expelled. Units on a tile with other units may not be expelled. Expelling an AWACS requires a Fighter-type unit.

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