Sieges/Embargoes?

[Bradlius]

I'm planning to capture a neighboring city fairly early in a Noble-level vanilla game. His city is well defended, and it may take me a few turns to capture it. It will make it especially difficult if he is able to build his own Swordsmen units while I'm hammering away at his City Defenses.
What I want to know is, if I destroy all the roads into the city, will that cut off his supply of iron from the rest of his empire? Or would it be sufficient to just camp my units on those roads? And what about rivers? His city is adjacent to a river, which also extends to several more of his cities. If I destroy all the roads, would he still be able to get Iron from the river?
I thought about trying several save-and-quit attempts to see what would happen, but that wouldn't really tell me if he had access to the iron or was just choosing not to use it.
Anyone know for sure?

 

[Zophos]

He will be able to use Iron in that city if he is (a) connected to any iron mine within his cultural borders (more on this below), or (b) connected to his capitol, and trading for Iron from any other civ.

A city is 'connected' to something if there is an unbroken path of roads (or railroads), rivers, coastline (with Sailing), or ocean (with Astronomy), with the caveat that roads do not connect directly to coastline (but do connect to rivers). A naval unit breaks any connections that pass through its square or any adjacent squares, so it is possible, though technically difficult, to establish a naval blockade. Camping a unit on a road does NOT, to my knowledge, break the connection, despite how counter-intuitive that might be. There is no way that I am aware of to block a river.

All that being said, the typical way of denying a resource to the enemy is by pillaging his mine(s), rather than trying to sever the trade connections.

 

[automator]

Your seige really shouldn't last long enough for him to build a sword, unless he's running slavery or drafting.