For a fantasy-themed empire building (somewhat) game, I'm looking for mechanics on different ways to expand an empire across different city-states.
You start with a city, and have the possibility of expanding your influence/control to other cities. These are likely to be non-player controlled cities during the early game, and more likely to be player controlled towards the end.
There should be some kind of trade-off for what kind of influence you wish to exert.
The most obvious means is via military.
You create some military units and lay siege until you defeat the defenders. The city you get may need much rebuilding, but it might be a more sure-fire way to capture a city, provided you throw enough units at it; but ultimately offer the most control. Mechanic-wise, this is simple enough to incorporate into already existing unit combat rules.
It's the other ways you might control/influence a city that are in need of some other mechanics. These ideas might represent a simple trade agreement to economic dependence, or some kind religious or cultural conversion. Do they require some kind of resource trading? Civilian or diplomatic units to perform some action? Does it require moving units across the map? Or simply allocating them to some kind of jobs?
What are the trade-offs? In comparison to military conquest, perhaps economic influence offers more immediate, but lesser, gains as opposed to absolute control of a wrecked city?
From a mechanic standpoint, I'm getting a mental block as to how I might represent progress towards these alternate means of control. Any ideas?
Interesting ideas so far.
You hit on the idea with grudge tokens, and it occurs to me that I would probably have to introduce a new resource or concept to handle city relationships. How different cities feel about you, and the overall mood of your own city - which could affect production or something.
Now this could get rather complicated and inelegant, but perhaps a simple binary quality could work. What I mean is, another city could either like you or dislike you and I'd only need a token for one of those cases, as the absence of a token would imply the other state. This could also possibly be three states: negative, positive, and neutral.
This concept could be coupled with some kind of default state for city relationships - which can even be printed directly on the map with regard to non-player cities for quick reference. Now that I think about it, I might only need to list if a city likes another city. Basically, if you piss one off, you piss off the other as well.
Here's how I see this could work:
You have a trade relationship set-up with non-player city Appleville. This gives you access to a resource you wouldn't otherwise have. This might be a strategic resource and/or be keeping your own citizens content.
Another city, Bananaville, has become problematic for some reason and you want to conquer it.
However, Appleville and Bananaville like each other. So when you lay siege to Bananaville, this causes them to dislike you, which in-turn causes Appleville to dislike you as well, thus dissolving the trade agreement. And the loss of the imported resource causes your own city to become unhappy.
So now you have to decide if you can handle the unrest in your own city, or find some other way to mitigate it.
I'm a little concerned at how I would track positive and negative mood factors in your own city, as this might become cumbersome. As I would need a step where a player compares current negative and positive unrest factors. And this adds time and complexity.
On the plus side, each player already has a city place card that tracks important info of your home city, so I could incorporate something into that. Maybe.
On the other hand, I could skip the "your own city mood" aspect and just use the city relationships which would be much simpler, and still create some interesting dynamics. But there is something to be said for having to keep your own citizens happy. Hmmmm.
Anyway, here's my current thoughts on various influence options:
Conquering - Medium length of time, gives absolute control, but city needs rebuilding.
Mechanic: Send military units to fight.
Trade - Quick to set up. Could provide resources, production, or population. Requires good relations
Resources: gives access to a resource
Production: provide extra production capacity,
Population migration: provides extra population, requires some kind of cultural upgrade.
Mechanic: Send (or set aside) a population unit to set-up and conduct trade.
Conversion - (religious, cultural, alliance) Takes a long time, requires good relations, but gives large (absolute?) control of a developed city.
Mechanic: Not sure. Influence tokens? Send populations units? (these kind of already function as influence tokens in someways)
I could set it so that each non-player city can only have one trade export active at a time. Players would then have to balance military and cultural expansion, lest some other player snap up trade agreements blocking others out.
At that point a player, may contemplate military action, or try to engineer a lowering of relations to dissolve the agreement, thereby freeing it up.