its complicated. yes. most people just say, "bound villages". but that means about jack shit.
bound village provide surplus goods, for the base product.
lets take Poros. (note, poros is southern empire, not Western empire as shown here)
Poros has 2 sheep villages. So, a wool weavery would be good right? those two sheep villages drive down the price of wool in Poros.
well no. Becuase, there is no demand for wool and wool clothing in Poros, or Onira, or Lycaron nearby.
ALSO, poros's prosperity is shit.
1. High prosperity cities, sell more shit.
2. look at local, supply, and look at nearby demand.
3. where to nearby villages take shit?
4. war, bandits, looters.
Poros again, does Onica olives go to Poros, or Zeonica? go to Onica, and follow the villagers, find out.
If onica takes olives to poros, then that is the correct answer there. Oil press. Theres going to be a much larger demand for Oil there, then wool products.
But still, poros is not in an ideal location, compared to say, Ortysia, Marunath, Epicrotea, Dunustica. These are the trade kings, in ideal locations bordering multiple nations, and trade goods.