Empire AI Part II – Planning

time for  part II of making an AI to play Empire

the metagame is a very important aspect of Empire, as we all know. The scoring heavily favors an AI that can O P T I M I Z E  P U N I S H, in terms of the meta.

applying pressure

so here’s what I’m looking at, in terms of strategy: you’ve got armies, right? These things are fairly OP unless you’re on like a map comprised of small islands (always a possibility idk). Right now, for scoring, you get points for the following two things: 1) how many cities you are in control of at the end of the game and 2) how many units you have at the end of the game.

now, armies are cheap (they can be built in a very small number of turns). Therefore, if you spam them (and they don’t die), you’re already racking up those sweet, sweet points just for owning these cheap units that your cities can pump out. Not only will spamming them help you get some points by default, it’ll also give you more of a chance to conquer cities.

viability in the meta

but why are armies so top tier? Well, there’s a few different reasons. Firstly, armies are the only land unit O_o. Land units are typically your bread-and-butter scouting/attacking units in games similar to this (I’ve played one – or more – of the Civ games at least more THAN ONCE, so that counts for something, right?), at least in the opening stages of a match. So right off the bat, armies are, at the very least, going to be your go-to units early on. Secondly, the water units take eons to build 😦 (don’t quote me on that). Even when you do build them, you might not be able to move them anywhere useful if you’re not on a map with optimal waterways.


however, water units are good for beating up armies passing by, and maybe for hanging out inside cities to defend them. Pretty cool, I guess 🙂 ? (but remember, they take a while to build 😐 )

good spacing

but you might also want some formations, so that your armies aren’t alone. I’m probably going to look into some sort of formation strategy

my plan is to have a formation system that lets you build a formation by specifying 1) how many slots are in the formation (the max number of units that can be in the formation besides the leader) and 2) where these slots are located in relation to the leader (the number of grid cells to offset them by). Then, the follower units will move only when they are out of alignment with the leader. Here are some example formations


  1. spam armies
  2. move towards unclaimed cities or explore (move in random pattern) if no visible unclaimed cities
  3. defend claimed cities
  4. make formations of armies to go fight and claim other players’ cities/units (focus more on cities, but fight passing units)
  5. maybe make some water units

wait a minute

what happened with my original exploration AI from last time? Well, as I said in my last post, I implemented a pattern-based pathing system. It actually turned out pretty well, and while it didn’t cover the whole map in 200 turns, it got pretty close. I ended up using the North, North, North, East, Northeast, Northeast, Northeast pattern. Now that I’ve put some more thought into my strategy for part II, I don’t think I’ll need a Blackboard system, but we’ll see.

the original exploration AI

-wednesday-david hartman


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