Most people prefer to finish the game ASAP and take whatever approach will get them the victory and maximum score. Some of us, however, enjoy the warfare aspects of Civ4. I like taking on the AI’s instead of just shooting for a space race or diplomatic victory. War is fun and it’s even more fun when you can fight with a wide variety of units, including tanks, modern armor, mech infantry, bombers, fighters, etc…
I measure my success by the exchange ratio. If I can take out every single AI while maintaining a kill ratio of 3:1, that’s a stunning military victory.
So this is not really a guide on winning Civ4, because there are many other guides. This is all about war. How you fight a war against a well armed AI.
Modern era
Armor units
Modern Armor and Tank should be promoted in 3 different styles.
Shock troops are the one you expect to die in large numbers due to leading assault on a city fortified with Mech Infantry. They should receive City Raider, and Barrage. If you chose civics such that you can have a third promotion right out of production, choose Combat I. If an unit survives enough assaults to get another promotion, choose Pinch. Blitz will be a non-factor because these shock troops won’t have enough HP to make a 2nd attack.
Cleanup troops are the ones who will go in when all defenders are at a fraction of their initial strength. Promotion order is Drill I, Drill II, Combat I, Drill III, Pinch. These units will usually survive and eventually become highly promoted.
Specialty troops are the units you built in the city with West Point. You only need 1 or 2 of each. Combat I, Combat II, Charge makes a specific anti-siege unit. Substitute Formation if you want an anti-Cavalry Tank unit, but it’s unlikely you’ll need many of these.
The unit mix should be 3:1 in terms of shock troops versus cleanup, since the core cities you’ll be assaulting usually will have 6-8 defenders. Expect to lose 40-60% of your shock troops in any given assault against entrenched Mech Infantry which has been softened up already with either an artillery suicide-charge or stealth-bomber air strikes, so plan accordingly when it comes to your post-conquest goals.
If the assault is against regular Infantry or Marine, then the loss ratio for shock troops should be in the 20-40% range. The shock troops should NOT be moved after the assault. Leave 2-3 full-strength gunpowder units in place, one of them with medic upgrade, to maximize healing. The only exception is in beachhead assault, where you must put everyone into the city in order to wait out the counter-attack.
Gunpowder Units
Infantry and Mech Infantry are in the same basic category. They are usually considered defensive units, but they are much more versatile than that. There are 3 basic types of Gunpowder units, and your options are going to be complex since you’ll likely have legacy units you upgraded. So the unit mix won’t be quite as static as armored units, which you can plan from day 1.
Especially valuable are those units who have been promoted from archers and longbowmen because those units can have Drill upgrades, which they keep even as Gunpowder units.
Shock troops are designated for city assault. These units are essential when facing a city with wall/castle because the 50% bonus can’t be reduced with bombardment. Sending anything except for gunpowder units makes the city a meat grinder. Combat I, Pinch, City Assault is the promotion order. Expect 85%+ casualty from units which make the assault.
Garrison troops are used to hold the captured territory. City Garrison, Combat I, and Medic are the promotion order.
Specialty troops are given Guerilla I and Guerilla II for a special hill-cover unit. , or the Woodman equivalent. For Infantry, in the pre-Gunship era, you may want to get Combat I, Combat II, and Pinch for a specialty anti-tank unit. Once promoted to Mech Inf, you can now fight Modern Armor on equal footing.
Gunpowder units are needed on a minimum of 1:4 ratio with the armor units in a large-scale assault. If you have 12 armor units (9 shock, 3 cleanup) then expect to carry at least 3 Gunpowder units. If this is the initial landing on enemy territory separated by ocean, the ratio needs to be reversed to 3:1 in favor of gunpowder (12 gunpowder for every 3 armor) in order to weather the initial assault.
Always keep the Infantry unit’s +25% vs gunpowder in mind. Against an infantry unit entrenched in a city guarded by walls, the defender has the 50% bonus in addition to the normal entrenchment. At 100% strength, that gives the defender 35 = 20 (base) + 10 (wall) + 5 (entrench) versus the armor unit’s 28. Bad odds. Even if you reduce the infantry defender’s base to 60%, it’s still 28 vs. 21 (defender).
An assault with an Infantry unit against the same 60% defender, the odds are better at 25 vs. 18 because the wall bonus no longer applies. Even better if the attacker has Pinch and the defender has Garrison because you apply the 25% bonus to a higher base and the defender’s bonus is only 20%.
If the defenders are composed of Marines or SAM Infantry, the advantage is even more pronounced. The Marines have a higher base, but the Infantry’s 25% bonus makes up the difference. SAM Infantry has a lower base and no gunpowder bonuses.
Mounted and Helicopter Units
In the modern era, both you and the AI can have a large number of gunships just because the inventory of cavalry units which was subsequently promoted. In some cases, it’s better not to promote because the main use of such mounted units in the modern era is defensive or for pillage.
The gunship is touted as an anti-armor unit, and there are no good promotion strategy other than Drill. Anything else is useless because it usually doesn’t survive combat. The AI is smart enough to cover their tanks with SAM infantry and other gunpowder units, so you’ll rarely get a chance to use your gunships against them anyways.
Instead, use gunships for raiding. Uniquely, they can move immediately upon unloading from a transport. The initial transoceanic assault will trigger a massive response and gunships will help you survive it by cutting all rail lines around the city you’ll be assaulting.
Use 1 movement to unload, 1 more to get into position, and the remaining 2 to pillage. You need to cut ALL the railroads into the entry city to prevent the 1 MP units from reinforcing. Of course, you should have cut the lines around your initial landing site first.
After the initial landing, take the surviving gunpowder units to cover the gunships into proximity any nice geographic features like hills. Create a fire break wherever possible by cutting railroads. Gunships are the only unit which can cut an improved tile in a single turn, although you should plan to sacrifice them. Stalling the enemy counter-attack is well worth doing even if you lose several gunships.
If you start a war without Gunships, Cavalry is your only option. Once Infantry is in play, Cavalry is useless anyways and their only use is to pillage. If you have any older units left like Horse Archers, etc…, now is the time to use them. You have to use (and lose) twice as many mounted units, but the result will be the same. It’s a shame that Explorers can’t pillage, because they’d otherwise be the ideal.
Important Note: Due to a bug in the patch, a group (2 more more) of gunships without stack-attack turned on can actually occupy a city. Thus it’s actually possible for an all-gunship assault to take enemy territory.
Siege Units
In modern warfare, there is really only 1 siege unit – the artillery. The Machine Gun is worthless and don’t even bother bringing it when planning an assault. Its usefulness is strictly against the likes of Cavalry and Rifleman. Once you have infantry, you don’t need MG’s.
The artillery, however, should be your best friend. On an assault, sacrificing 3-4 artillery units is worth it as long as you save a couple of tanks or mech. infantry units from destruction. The slow movement isn’t going to matter in your initial beachhead assault, and your operating tempo will slow down to allow units to heal anyways, so you have time to let large artillery divisions move forward. Unlike the catapult or Cannon, the Artillery has enough strength to make a halfway decent defender, and none of the “modern” units have anti-siege bonuses built in. Artillery comes in two varieties – general and assault.
General artillery should have Accuracy and Barrage. That makes them suitable both as bombardment if you don’t have bombers (or don’t want to use them) and as shock troops. The assault artillery is either units built in the West Point city or a general artillery which got promoted enough to get Barrage II.
In an assault after all cultural bonus has been worn down, pick your highest Barrage artillery unit and send them in to die. Expect 60-80% mortality rate, and the goal is to wear down the defenders such that you have a definite superiority in attack strength. For every 3 units in the city, expect to use 1 artillery assault. So if a city is defended by 9 units, plan to use at least 3.
A crucial point is that in the initial beachhead assault, you MUST hold at least 4 artillery units in reserve because the AI will inevitably send its most powerful counter-attack immediately. Assuming you brought the right unit mix, the gunships should have cut the roads. That will force the AI to stack up its units instead of just rushing in for the attack. This is where the artillery saves your beachhead by doing so much collateral damage to the stacked up units that you get breathing room to have your transports make another round-trip with reinforcements.
Naval Units
In the convoy system, the only 2 units that matter are Battleship and Transport. You don’t need to have carriers, destroyers, etc… unless you seek naval superiority, which really isn’t necessary. By the time you are in a modern world war, the health bonus from fish, clam, etc… are no longer critical so the AI is welcome to parade their naval units up and down the coast without interference. If they deny your border cities of the sea-based foods, it’s likely that war weariness will reduce your workforce to the point where it doesn’t matter anyways.
Transports should be given Flanking and Navigation I to bring them up to 6 MP. That puts their range the same as the Battleship, which should receive all the Drill Bonuses possible. You won’t need flank or navigation because the BB’s aren’t going anywhere once they are on station.
In general, you should choose a common embarkation point for transports. Every 6 MP’s, station 2 BB’s as the convoy guard point. If the ocean is 3 transits wide, you’ll need 2 BB stations with a total of 6 units in order to provide relief. All transports, coming and going, will hald on the BB-guarded spots. In general, the AI doesn’t like to take on guarded transports without good odds and 2 BB’s are long odds.
However, if those are the only places where naval units are found, then the AI will go for them. That’s why you should be producing transports for use strictly as bait. Load them up as they are built with a single low-value unit and just send them into the deep blue seas. Losing them keeps the AI navy busy elsewhere while you truck in dozens of new units. To sustain an assault, airlifts alone aren’t enough unless you want a grinding war.
Also remember that the transports have enough attack points that if there is a severely injured BB or destroyer hanging around, feel free to just take him out with an empty transport.
Air Warfare
Most of the strategy articles talk about Stealth Bomber, but that is at the end of the tech tree. Surely people have gone to war while armed strictly with Tanks, Artillery, Infantry, and Bombers?
In the Industrial Era, the Bomber is of limited utility. It takes at least 6 attacks to reduce a 100% cultural defense down to zero, and that assumes you can obtain a good base. You’ll spend a lot of time rebasing bombers, because a base suitable for assaulting one city won’t be suitable for another. Given how much the AI likes to use SAM Infantry, the Bomber is in deadly danger as soon as they have Rocketry, which comes a LOT sooner than Stealth Bomber. The Bomber is also relatively worthless in an air strike role unless the enemy AI is so far behind as to NOT have SAM Infantry or Fighters.
At Prince or above, how likely is it that an AI which you’d have to plan a trans-oceanic assault on doesn’t have SAM Infantry?
In short, Bombers are almost a complete waste of time in the city assault role. You’d be better off using the production capacity to produce an artillery
Fighters are also nearly completely worthless. They spend too much time trying to re-base as operations move forward, and the production is better spent on another SAM Infantry or Mech. Infantry unit if you wanted anti-air protection. Unlike fighters, those units are actually useful for something else.
The only air unit even worth building is the Stealth Bomber, which is of course set to be wayyyy too powerful. With a big stack of stealth bombers (12+) not even a city protected by Jet Fighters can reasonable hope to protect it from bombardment. As long as you rest the Stealth Bombers to heal any time they take damage, you can expect to lose less than 1-in-10 even after 40+ rounds of combat. There’s no need to discuss how to use these.
Tactics
Some random thoughts, in no particular order
Dealing with Gunships
Sending out any kind of an armor force of Tanks or even Modern Armor without protection is an open invitation for AI gunships to swoop in, and as discussed, the AI always has a lot of gunships since they are upgrades from Cavalry. How to deal with them?
A lot of people like to use SAM Infantry, because of the 50% bonus. Bad idea. Even with the bonus, they don’t measure up to the Mech Infantry’s attack power. And SAM Infantry can’t keep up with tank units. Best to leave these guys back in your conquered cities as air cover.
If you don’t have the Mech Infantry unit, you should bring along extra Gunships instead. It’s a fair fight, and Gunships have little combat role in the city assault anyways since they can’t attack an entrenched SAM unit with any kind of success. As part of a stack with tanks, the enemy SAM Infantry can’t get at them and you just need to have more Gunships than the enemy can bring the bear.
In the event there are gunships covering a city, expect to spend a couple more artillery so that your own tanks have a fighting chance at beating them. Infantry against gunship is not a good deal either, and it’s better to spend more artillery units.
Railroad Raider
Besides the vital necessity of creating a fire-break around your beachhead city, you should have obtained a world map at some point which gives you a look at the terrain. Look for choke points where the road network narrows and plan to drop a transport with a few gunships on that spot. Because of the 4 MP’s, a gunship can unload, pillage, and get back on the transport in a single turn.
Any enemy choke point which comes too close to the ocean is your prey. Stay away from squares with towns. Although the plunder is nice, it takes too long to get all the way down to the railroad.
Unlike previous versions of Civ, you can’t cross an entire continent on rails in a single turn. Any degradation of the rail network which causes units to detour is worth doing. A transport loaded with 4 gunships can move down the coast and blow away 2-3 squares worth of railroads in a single turn.
Feint
Use the railroad movement cost to your advantage. In Civ4, it’s much harder to reinforce. If you have the units, start a false landing with ONLY the crap-units you can’t use (machine guns, un-upgraded cannons, old riflemen, unneeded cavalry) in an inaccessible spot near a bad city. The AI will respond in force regardless, and it’ll draw all those 1 MP units too far from your actual beachhead to respond the same turn.
That extra turn gives you the breathing space make sure you cut rail links. This tactic is best combined with Railroad Raider. If you draw them out and then cut the roads behind them, you can comfortably settle in before they reach you.
Research Priority
Considering the relative useless nature of bombers, is it really necessary to research Radio early on?
Instead of 6k on Radio, get Rocketry first because Gunships are a lot more valuable.