In Civilization IV, a unit with first strikes can damage its opponent without retaliation. Immunity to first strikes negates them. First strikes are an inherent ability of some units and also granted by the Drill series of promotions. Immunity to first strikes is an inherent ability of some units, and it is granted by the Flanking II promotion.
Effect in Combat[]
When two units engage in combat, one or both may have one or more first strikes. Similarly, one or both may be immune to first strikes. The numbers of first strikes that both units get are compared. If they are equal, they cancel out and no first strikes are computed. Otherwise, the numbers are subtracted, and the unit with more first strikes gets the difference as first strikes. However, if the other unit is immune, no first strikes are resolved against it.
Each first strike resolved is treated as a regular combat round, except that the first striker takes no damage regardless of the outcome of the round.
Inherent First Strike[]
The following table summarizes units and their inherent first strike abilities:
| Unit | First strikes |
|---|---|
| Archer | 1 |
| Bowman | 1 |
| Cho-Ko-Nu | 2 |
| Crossbowman | 1 |
| Keshik | 1 |
| Longbowman | 1 |
| Machine Gun | 1 |
| Modern Armor | 1 |
| Navy SEAL | 1–2 |
| Oromo Warrior | 1 |
| Samurai | 2 |
| Skirmisher | 1–2 |
| Stealth Destroyer | 1–2 |
Immunity[]
The following units are immune to first strikes: