Combat

1:59 Civilization 3 combat is a series of rounds: in each round the attacker's chance to win is its attack divided by the sum of its attack and the defender's modified defense, the loser of the round loses one hit point, and the battle goes on until one unit has none left, per the Complete manual (pp. 106-108). A unit's experience sets its hit points (conscript 2, regular 3, veteran 4, elite 5), and terrain, fortifying, Walls, Fortresses and city size raise the defender's number. Civilization 2's firepower is gone (p. 58), so every round deals exactly one hit point.

Quick facts

Sources: Civilization III Complete manual, pp. 32, 58 and 104-111; Prima's Official Strategy Guide, pp. 173-175; Civilization III FAQ: Combat.

How a battle is decided

A battle starts when a unit moves into a square held by a rival unit or city, and it is resolved at once, per the Complete manual (p. 105). If several units share the defender's square, the one with the highest defense defends; a unit that cannot defend itself, such as a Worker, Settler or Scout, is captured without a fight.

Each round compares the two numbers. The manual's example is a Knight (attack 4) attacking a Spearman (defense 2): the total is 6, so the Knight wins about 66% of rounds (4 out of 6). Behind Walls, which add 50%, the Spearman defends at 3, and the Knight's odds fall to 4 out of 7 (Complete manual, p. 108). Prima's guide gives the same formula with a Swordsman (3) against a Warrior (1): 75% per round (Prima, p. 173).

Every lost round costs one hit point. The battle "rages until one or the other completely loses its health bar"; a unit can win every round and take no damage, or the two can trade blows until even the winner is badly hurt (Complete manual, p. 108). A winner with movement left can keep moving, and some units can attack again.

If the defender was the only unit in its square, the winning attacker moves in; if other units remain, the attacker stays where it was (p. 105). Units are listed with their numbers on Units.

Defense bonuses

Source: Prima's Official Strategy Guide, p. 173 (Table 8-5), 2001; Civilization III Complete manual, pp. 107 and 110, 2005.

1:20 Bonuses add together, each as a share of the unit's base defense. Prima's example is a Marine, defense 8, fortified in a fortress: 8 + 4 + 2 = 14 under its +25% fortress figure (Prima, p. 173). Walls stop counting once a town reaches size 7, because a city already gets the same +50%, the Complete manual notes (p. 110). The terrain values are on Terrain and Workers.

Fortresses do more than defend. Workers can build one on any land square after Construction; units inside get the bonus and free shots at enemies passing by, and a Barricade, which the 2001 and Play the World manuals do not mention, doubles the Fortress's bonus and stops enemy units moving past until the next turn (Complete manual, pp. 110 and 115).

Why a Spearman can beat a Tank

4:28 A Spearman can beat a Tank because Civ 3 rolls every round on the ratio of the two numbers, not on a fixed outcome, and an ancient defender with bonuses still wins some rounds. Using the manual's rule and Prima's additive bonuses, a veteran Spearman (defense 2, 4 hit points) fortified on a hill defends at 4 (2 + 1 + 1). A regular Tank (attack 16, 3 hit points) then wins each round 16 out of 20 times, 80%. The Spearman needs three wins before it loses four rounds, which works out to roughly a 10% chance: about one such battle in ten. That figure is our arithmetic from the Complete manual's "approximately" stated rule (p. 108); the game's exact calculation is not published.

8:58 Prima's own advice is plain: "don't expect a Spearman to hold off an invading platoon of Tanks", and upgrade old defenders, city defenders first (Prima, pp. 175-177). Bombarding first, attacking with more units, and using elite or veteran attackers all shift the odds back.

Experience and hit points

22:29 Experience means hit points in Civ 3. New units generally have 3, veterans 4 and elites 5 (Complete manual, p. 107), and conscripts, which come from the draft and from barbarian villages, have 2 (Civilization III FAQ). Prima stresses that rank no longer changes attack or defense, only staying power (Prima, p. 174).

Barracks, Harbors and Airports build veteran units. The Militaristic trait makes cheaper military buildings and more frequent promotions to regular, veteran and elite, per the Complete manual (p. 26); see Civilization Traits.

9:39 An elite unit that wins a battle may produce a Great Leader, who can rush a wonder or form an Army. Prima puts the chance at 1 in 16, or 1 in 12 with the Heroic Epic (Prima, pp. 171-172). Leaders and Armies have their own page: Great Leaders and Armies.

Healing and retreat

Damaged units heal by skipping a turn. A unit inside a city heals faster, and Barracks (ground units), Harbors (ships) and Airports or Carriers (aircraft) restore full strength in one turn; but no unit heals inside a foreign civilization's borders unless you own Battlefield Medicine (Complete manual, p. 107). Prima puts normal healing at one hit point per inactive turn (Prima, p. 174).

6:59 Fast units retreat. A ground unit such as the Horseman fights until it has one hit point left and then withdraws, unless it is surrounded or its opponent is another fast unit (Complete manual, pp. 105-106); Prima counts every unit with movement 2 or more as fast (Prima, p. 174).

Bombardment

2:44 Bombardment is a ranged attack without risk. Artillery units (Catapult, Cannon, Artillery, Radar Artillery) and the warships Frigate, Man-o-War, Ironclad, Destroyer, Battleship and AEGIS Cruiser can strike a square within range without moving into it, and the attacker takes no damage (Complete manual, p. 109). Jeff Briggs, Firaxis's president, presented it before release as a way to soften city walls and fortresses for the units that follow (Firaxis: War and Battles in Civ III).

A bombardment hits anything in the square: units, Walls and Fortresses, population or city improvements, chosen at random except in precision bombing (Prima, p. 175). Prima calls bombarding units "equalizers" that chip away at the hit points of superior defenders. The Byzantine Dromon of Conquests "has Lethal Sea Bombardment", per its official profile; no source read states a general rule for lethal bombardment in Conquests.

Play the World added automatic bombardment: bombard, bombing and precision bombing orders repeat every turn until you stop them (Play the World manual, p. 14; Complete manual, p. 109).

Air, naval and nuclear combat

Only fighters fight other aircraft. Units flying air superiority missions engage enemy aircraft entering their defensive range, half their operational range, and may shoot them down before they strike; air units defending a city get no bonus from its improvements, even SAM Missile Batteries (Complete manual, pp. 103 and 109).

Ships can blockade. With ships on every sea square around an enemy Harbor, no trade gets through (Complete manual, p. 110). The Coastal Fortress adds 50% to a city's defense against naval attack and fires on passing ships.

Nuclear weapons hit everyone near the target. Every unit in the target square and the squares around it, yours included, has a 50% chance to survive, the city loses half its population, and the land around is polluted; the defense is the Strategic Missile Defense Small Wonder (Complete manual, pp. 104 and 111).

Barbarians

Barbarians come from encampments that hold gold, and they pillage undefended cities rather than capture them, per the Complete manual (p. 56). Prima lists a combat bonus for the player against them by difficulty, from +400% on the easiest level to none on the hardest, using its own level names (Prima, p. 15), and the Great Wall doubles your units' combat values against them. See Difficulty Levels.

Reloading does not change the result

Civ 3 can lock its random numbers into the save. With the setup option Preserve Random Seed checked, reloading a save and fighting the same battle again gives the same result, the Complete manual explains (p. 32), as did the Play the World manual (pp. 8-9).

Soren Johnson, the game's co-designer, wrote that Civ 3 first saved the seed so reloading could not change combat results, that some fans "felt that the game was cheating", and that it became an option, off by default (Designer Notes: Water Finds a Crack, Jun 12, 2011).

Frequently asked questions

How does combat work in Civ 3? In Civilization 3 a battle is fought in rounds; each round the attacker wins with a chance of attack / (attack + defense), the loser loses one hit point, and the first unit to run out of hit points is destroyed, per the Complete manual (p. 108).

How many hit points do units have in Civ 3? Civilization 3 units have hit points by experience, not type: conscripts 2, regulars 3, veterans 4 and elites 5, per the official FAQ and the Complete manual (p. 107).

Why did my Tank lose to a Spearman in Civ 3? Because Civilization 3 rolls each round on the ratio of attack to modified defense: a fortified veteran Spearman on a hill defends at 4 against a Tank's 16, so it still wins one round in five and, by the manual's rule, about one battle in ten.

What does fortify do in Civ 3? Fortifying adds 50% to a unit's defense in Civilization 3, per Prima's guide (p. 173), and it adds to terrain, city and Fortress bonuses.

What does bombard do in Civ 3? Bombardment lets Civilization 3 artillery, warships and bombers attack a square within range without risk, damaging units, Walls, population or improvements, per the Complete manual (p. 109).

Do veteran and elite units hit harder in Civ 3? No. In Civilization 3 a veteran or elite unit only has more hit points (4 or 5), not a higher attack or defense, per Prima's guide (p. 174); elite winners can produce Great Leaders.

Does reloading change a battle in Civ 3? Not with Preserve Random Seed checked: Civilization 3 then stores the random seed in each save, so the same battle gives the same result, per the Complete manual (p. 32).

Sources

• Sid Meier's Civilization III Complete manual, Atari and Firaxis Games, 2005
• Civilization III: Play the World manual, Infogrames and Firaxis Games, 2002
• Sid Meier's Civilization III: Prima's Official Strategy Guide, Prima Games, 2001
• Civilization III FAQ: Combat (archived), Infogrames and Firaxis Games, Mar 2002
• War and Battles in Civ III (archived), Firaxis Games, 2001
• Conquests profile: Byzantines (archived), Atari and Firaxis Games, 2003
• GD Column 17: Water Finds a Crack, Soren Johnson (Designer Notes), Jun 12, 2011
• Be Better At Combat | Civ 3 Tutorial, Suede, Oct 17, 2024 (video)
• CIVILIZATION III HD! ► The Legendary Civ 3 Looks & Plays Awesome, GamerZakh, Apr 13, 2018 (video)
• How To Play Your First Game Of Civ 3, Suede, Feb 12, 2020 (video)