Simple Domains: Trade Routes and Tributaries

Central thrust: link wilderness-level travel and trade to domain trade income by establishing "routes", allowing some improvement to one's domain under Simple Domains without having to track population

One of the annoying things with Simple Domains is the urban population.  I'm also more interested in settings where city-states and tribes are the norm, rather than feudalism.  Consequently, different rules for and assumptions about organizing realms seem appropriate.

I don't really like ACKS' default population growth as a domain "advancement" mechanic because 1) it's boring (spend money or wait time, counter ticks up, spreadsheet recalculates), and 2) it's unreasonably fast (yeah, there's some justification about "time of upheavals and migrations", but that's not always reasonable).

It occurs to me that domain "advancement" might still be doable with static population numbers via mutable trade routes.  Opening a new trade route between two domains entails clearing it to some reasonable degree, and then leading a ship or caravan along it.   I've been thinking about "threat" primarily affecting edges of the trade graph; a threat closes the edge, then if left unaddressed might spread to more edges, and if it holds all the routes in to or out of a particular town, the town comes under its thumb as well.  So I'm not really talking clearing all the hexes on the route, just dealing with things big enough to threaten a caravan (bandits, orcs, griffons, dragons).  Once a route is cleared, maybe a seasonal encounter roll can bring monsters back to it.

Once the route between two settlements is safe and you demonstrate this by leading a ship or caravan across it, imitators follow and trade along the route becomes regular, allowing the rulers of each end to gather additional market taxes.  If the additional market revenue from trade get high enough, the market class improves.  This lets the trade mechanic fill in for the "extra urban families from vassals" problem that Simple Domains had before.  On the downside, allowing market classes to change like this opens up all sorts of weirdness if you use market class for anything (like trade range, or calculating how much trade income is generated), and could lead to undesirable positive feedback loops.

What I like about this idea is that it links the wilderness game to the domain game with travel.  Your players get to go see the rest of the campaign world in order to make their domain stronger, rather than grinding through hex-clearing.  My players often seem to want caravans and ships in the mid-levels anyway.  At low levels you play "caravan guards", at mid-levels "caravan leaders", and at high levels "that guy who sponsors caravans led by henchmen".  It also opens up structured interactions with diplomacy.  Going to war with a domain generally means closing of routes between the combatants, and you may attack trade routes they have with other domains as well to reduce their trade income.  This might anger their trade partners, leading to embargo or entering the fight against you.  Conversely, a small domain coerced by a larger one might not be willing to trade with their overseer's rivals due to the sword looming over their heads, unless you can make them assurances of protection.  A domain defeated in war might become a tributary state as a term of surrender, sending its trade income to the domain the subdued it.

The tricky part is getting the numbers right - big enough to be worth bothering with, small enough to not spiral out of control, consistent with ACKS' existing trade rules, and simple enough to not be a huge hassle (ie, "just treat it as a network of sources and sinks for various goods, and you're adding a new link, which changes traffic patterns and directs trade through certain nodes which changes the tax income for those nodes"...  like yeah, I could do that, programmatically, but I don't want to need a computer).

Another interesting question is interaction with all the other parts of ACKS.  Does trade with settlements of different culture, terrain, "tech level", etc generate more income?  Interaction with monopoly?  Thieves' guilds?  Our favorite class, the venturer?  Seasonal variation in trade income (less in winter, more in summer)?  How do trade volumes or revenues relate to infrastructure like roads?  (Can we spin this into a reason for players to build and maintain roads, which they also seem to often want to do?)

I don't know if this would actually be simpler in practice than population growth.  But I do think it might be more fun.

A third approach to "domain advancement", and one which players seem to for push historically, is building up local industries and institutions.  I think this is actually fairly easy to adjudicate under ACKS' core rules, but it's not very profitable, and it could stand to be quantized, Kingmaker or Fields of Blood style - drop 10kgp plus some monthly maintenance on a Shipyard, and now you can buy ships as if your market were one class bigger.  Domains have a limited number of Industry slots based on size.  This would certainly be philosophically consistent with Simple Domains, so maybe it warrants further development.