What exactly are trade routes?

For some reason, this concept absloutley alludes my understanding. I feel like it's blatantly obvious, but I'm just not getting it. Basically, I don't know what they are. I understand that they are creataed by connecting two cities via road or river or something, but who is your daddy and what does he do? (what are they and what do they do?)

Is it something that's done automatically? Is there a way I can maximize their effectiveness by managing them?

This has been bothering me since CivIII. I can occasionally win on Prince, and if that's the case, I feel like I should at least understand all the basic mechanics of the game.

Thanks in advance.

They are set up automatically to the most productive cities.
To have foreign trade routes, you must have an 'Open Borders Agreement.
To have overseas trade routes, you must have Astronomy.

Welcome to the Forums UConnTO.

As for managing them properly, here are a few guidelines:

If you sign Open Borders with a leader who is not connected to your trade network, you will not receive trade routes from that civilization (or the commerce it generates).

Civilizations that are farther away from yours usually produce more commerce for you through Open Borders. The least useful trade routes are ones between your own cities (since that's as local as you can get).

If you see domestic trade routes in your cities, sign Open Borders with someone to replace them with foreign trade routes.

If you've signed an Open Borders agreement with exactly one leader, and you still have domestic trade routes, then that leader is benefitting more from the Open Borders than you.

If you've signed Open Borders agreements with multiple leaders who are connected to your trade network (and not blocked), and one civilization is giving you few or no trade routes, then that means that trade routes from that civiliztion are not worth enough to outpace the competition. Furthermore, if that civilization has fewer Open Border agreements than you, then not only are you not benefitting from Open Borders with that civ, but that civ is also greatly benefitting from your generous contributions. If you find that you have such a leech, cut him off immediately by cancelling Open Borders with him.

Have I to find and reveal the enemy cities, to have a trade route with them? Or it's enough if I have met the leader and open the borders, even if I don't know any of his cities?

The second one.

Is it something that's done automatically? Is there a way I can maximize their effectiveness by managing them?

Click to expand...

There's lots of ways to maximize the effectiveness of trade routes. In fact it's possible to power your economy by almost trade routes alone.

First coastal cities. Only coastal cities can build the two improvements that improve trade route yields, Harbors and Custom Houses. Plus only coastal cities benefit from one of the cornerstones of pursuing a trade route strategy, the Great Lighthouse.

Explore! Get a galley out sooner rather than later. Follow the coast and make contact with distant civilizations. Sign open borders and start bringing in that trade income from distant routes.

Avoid War. Not only do you get a bonus on your trade routes for "sustained peace", trade routes that pass through your enemies territory will be cut off for the duration of the war robbing you of income.

Sailing techs. The sailing line of techs is all about trade routes. Most of them allow you to more effectively explore for trading partners, increase the yield from trade routes (compass), or even give you more resources to trade around with all these civilizations you're meeting (calendar).

Astronomy deserves some special mention. Oversea trade routes are huge, giving huge bonuses to the yield of the trade route, easily bringing in 8-10 commerce a turn (on coastal cities). That's better than a fully developed cottage, even with printing press and free speech - and consider that each city can have from four to five of them which require no citizens to work. That's massive. If you have some overseas trading partners and a decent number of coastal cities, astronomy can easily increase your research 50 - 100% on the turn its discovered.

One pitfall here. Enemy AIs love mercantilism which will sever their trade routes with you. If mercantilism becomes widespread you have some options.

A. Switch to mercantilism yourself, and go for Statue of Liberty w/ Representation. (If you can't get the foreign trade routes might as well get the free specialist instead)

B. Use espionage or diplomacy to switch their economics back to decentralized or free market.

C. Tech up to communism and trade it around. AIs tend not to like Free Market enough to switch to it once they get Economics, but they'll happily switch to State Property once they get Communism and this will open trade routes back up.

To sum up consider trade routes as an economic strategy if some of the following are true:
- You can secure a lot of coastal real estate - REQUIRED
- Can build the Great Lighthouse
- Suspect that there is an AI or two lurking overseas
- Have some resources calendar can open up
- If you are playing a civ that has a sea-based UU or UB (Vikings, Portuguese, Carthaginians, ect.)

There ya go, that's most of what I know. Feel free to ask more questions, tho.

@r_rolo1

What conditions trade routes need to actually "connect" has me a bit confused as well.

Say I have sailing before the wheel (common if I'm going for GLH), if I plop down a coastal city it won't be connected to my trade network until I actually scout out a coastal route to it from my capital.

On the other hand, I see trade routes all the time to cities I have not yet discovered. Is it possible that one civ needs to see the other city in order to get trade routes back and forth?

So I tested it on world builder and the way it seems to work is that the game combines your map and the map of the civ your trading with to determine route possibilities. This means that you can discover a civ with your caravels that a coastal route exists to. However you won't be able to actually trade with this civilization until either you or him discover the coastal route (until astronomy that is).

Trade routes are free money.