Want to know the biggest secret to winning wars in Civilization 6? It’s not about having the biggest army. It’s about understanding the ground you’re fighting on. The map isn’t just a pretty background for your empire; it’s an active player in every single battle. Learning how to use the landscape, from a tall hill to a nasty marsh, is what really separates the pros from the beginners.
I want to break down exactly how terrain and combat work together in Civ 6. We’ll go way beyond the basic ‘hills are good’ idea and get into the specific numbers and strategies that let you turn any piece of land into a deathtrap for your enemies. We’re talking about how to use the environment to set up defenses they can’t break, plan ambushes that wipe them out, and take their cities like a pro. Every tile on the map is a chance to win, and I’m going to show you how to use every single one.
The Core Modifiers: Your New Best Friends
Before you can start planning epic battles, you need to know the basic rules. Almost every tile in Civ 6 gives a defensive bonus or penalty to any unit standing on it. This is the foundation of all good tactics. An attacker’s strength gets compared to the defender’s modified strength, so a unit in a good spot is way, way tougher.
Here are the fundamental defensive modifiers you should burn into your brain:
- Hills: +3 Combat Strength (CS) for the defender. Simple, common, and reliable.
- Woods & Rainforest: +3 CS for the defender. Just like hills, a solid defensive boost.
- Marsh: -2 CS for the defender. Avoid defending in a marsh at all costs. It’s a trap tile that makes your units weaker.
- Across a River: The attacker gets a nasty -5 CS penalty when striking a unit on the other side of a river. This is one of the biggest defensive advantages in the game.
And here’s the crucial part: these bonuses stack. A unit defending on a tile that’s both a Hill and Woods gets a sweet +6 CS bonus (+3 from the hill, +3 from the woods). If an enemy has to attack that unit from across a river, your advantage becomes massive. This is how you create ‘fortress’ tiles that can stop an army much bigger than yours.
On top of that, terrain affects movement and what your units can see.
- Movement Cost: It costs 1 movement point to enter clear, flat land. Hills, Woods, and Rainforests cost 2. You can use this to your advantage. Lure enemies into rough terrain so they use up all their movement just to get to you, leaving them open for a counterattack.
- Line of Sight (LOS): Hills, Woods, and Rainforests block line of sight for most units. This means your archer can’t shoot what it can’t see. But, if you put that archer on a hill, it can often see and shoot over forests or other obstacles on flat ground, which is a huge tactical plus.
Once you master these numbers, you’ll stop seeing a map of green and brown tiles. You’ll see a grid of +3s, +6s, and -5s—a web of movement traps and perfect firing positions just waiting for you to use them.
Using Hills: The Bread and Butter of Tactics
Hills are the classic defensive terrain in Civ 6. That +3 CS bonus is always there for you. But their real strength comes from how that bonus works with movement costs and line of sight.
Defensive Strategy: The Unbreakable Shield
The most obvious way to use hills is to build a defensive line. Just by placing your melee units on a chain of hill tiles, you create a wall. An enemy warrior with 28 CS attacking your warrior on a hill is basically fighting a 31 CS unit. That small difference changes everything, making your units take less damage and hit back harder.
Example: The ‘300’ Defense
Picture this: an early-game rush is coming your way. The enemy has three Warriors and a Slinger, and you’ve only got two Warriors and an Archer. On an open field, you’d be toast. But then you spot a chokepoint between some mountains and a line of hills.
- Positioning: You stick your two Warriors on adjacent hill tiles, blocking the pass. Your Archer sits on a hill right behind them.
- Enemy Approach: The enemy Warriors have to use their whole turn just to move onto the flat ground in front of your hills. They can’t even attack.
- First Strike: Your Archer, safe on its perch, has a clear shot and starts peppering the exposed enemy. Your Warriors, dug in on their +3 CS tiles, are ready for the attack.
- The Grind: When the enemy finally attacks, they’re fighting uphill against your fortified units. Your Archer keeps providing support, finishing off anyone who gets hurt. Your line holds, and you wipe out their army while taking almost no losses yourself.
That’s the power of hills. They let you control the fight.
Offensive Strategy: The Archer’s Perch
When you’re on the attack, hills are your ranged units’ best friend. Putting an Archer, Crossbowman, or Bombard on a hill gives you two huge advantages:
- Better Range and Sight: A hill often gives your ranged unit the line of sight it needs to shoot over things like forests or even your own front-line troops. This lets you hit valuable enemy units that thought they were safe.
- Safety: While your ranged unit is shelling the enemy, it still gets the +3 CS defensive bonus from the hill. This makes it much tougher for fast enemy units to rush in and take out your precious artillery.
Example: Sieging a City from the High Ground
You’re about to attack a walled city. The main approach is across a river, which is a terrible idea. But, just south of the city, you see a bunch of hills.
- Set Up a Fire Base: Instead of sending your melee units to die at the river, you first move your Crossbowmen and a Catapult onto the hills that overlook the city.
- Bombard with Impunity: From up there, your siege units can ignore the river penalty and start blasting the city’s walls and defenders. The city’s own ranged attacks are weaker because your units are on defensive terrain.
- The Final Push: Once the city’s defenses are smashed, you can finally move your melee units in to capture it, keeping them at full health thanks to your smart positioning.
Fighting in the Woods: Ambushes and Guerilla Tactics
Woods and Rainforests give you the same +3 CS defense as Hills, but they bring a whole different tactical flavor based on hiding and slow movement. This is where you can get sneaky.
The Defensive Thicket: Bleed Them Dry
Just like with hills, a line of woods can be a strong defensive front. A unit on a wooded hill gets a massive +6 CS bonus, making it incredibly tough to kill. The big difference from hills is that woods block line of sight more. This can be good and bad. It protects you from enemy archers, but it also means your own archers can’t see much.
This makes woods the perfect place to force close-quarters fights on your own terms. An enemy army that walks into a dense forest is basically blind. They can’t see what’s waiting for them, making them perfect targets for an ambush.
Example: The Forest Ambush
The enemy has a better army with strong ranged units. You know you can’t beat them in an open field battle. So, you pull your army back into a big, dense forest.
- Set the Trap: You hide your melee units on wooded tiles just out of the enemy’s sight. You position your own ranged units to cover the paths you think they’ll take, even if they can only see one tile ahead.
- Lure and Isolate: The enemy army marches into the forest. Their movement slows to a crawl (2 points per tile), and their army gets separated. Their powerful ranged units are now useless because they can’t see anything.
- Spring the Trap: As an enemy unit blindly stumbles forward, your hidden units jump out. Your melee fighters swarm the isolated target. Because the fight is up close, the enemy’s ranged advantage is gone.
- Hit and Run: You focus all your attacks to destroy one unit at a time, then fade back into the trees. The enemy, unable to use their full army, gets picked apart piece by piece.
Leveraging Unique Abilities: Vietnam’s Playground
Some civs are just masters of fighting in the woods. Vietnam, led by Bà Triệu, is the best example.
- Combat Bonus: Their units get +5 CS when fighting in Woods, Rainforest, or Marsh tiles (+10 in their own territory!). This bonus stacks with the +3 from the terrain itself. A Vietnamese Warrior in a forest inside their own borders defends with an insane +13 CS bonus.
- Movement Bonus: Their units also get +1 Movement if they start their turn on these tiles (+2 in their territory). This lets them run circles around any opponent in the forest, striking and retreating before you can react.
When you’re playing as or against Vietnam, the forests become the most important part of the map. As Vietnam, you should always try to fight there. Against them, you have to find a way to drag them into the open, or you’re going to have a very bad day.
Using Rivers: The Ultimate Defensive Barrier
Rivers are one of the most powerful, and most overlooked, defensive tools in Civ 6. They don’t give a bonus to your defending unit; instead, they give a huge penalty to the attacker. A melee unit attacking across a river gets a -5 CS penalty. That makes charging across a river a terrible, and often stupid, move.
The River Defense: Your Natural Moat
The best way to use a river is as a natural moat for your cities or your army. By setting up your units on your side of the river, you force the enemy to make a bad choice: either attack you at a massive disadvantage or waste turns looking for a place to cross.
Example: Holding the River Line
An enemy army is marching on your capital, but there’s a wide river in front of it.
- Form the Line: You place a line of Spearmen right on the riverbank. Behind them, you put your Archers.
- The Meat Grinder: The enemy has to move up to the opposite bank. When they attack, they suffer the -5 CS penalty. Your Spearmen, who are strong against cavalry and take reduced damage, easily hold the line. Meanwhile, your Archers are safe behind your line, firing away at the attackers stuck on the other side. The river becomes a kill zone. Any unit that tries to cross gets shredded.