Hi, my name is Chris. I've been playing this game for a while now and most of that time spent experimenting with the economy and trade systems within the game. I love how the economic system is designed to have many ways to use buildings to handle trade. It's unbelievable someone is able to create and balance such an extensive building system.
Well, I couldn't get my hands off that game the last days and collected all my impressions and ideas which i want to present you in a "guide" to trade with using trade centers. It's more of a story to how to setup a centralized trading system and by the way things of the trading system getting explained.
if you find any errors or you want to contribute something to the guide i will be happy if you tell me to either correct or add things to this guide.

Well ok, have fun with reading and thanks alot for reading in advance!
Chris

It's just all about optimizing trade income by making heavy use of moving trade goods around and using Trade Hubs for this purpose. Besides that centralized trade also affects the optimization of direct income generated by buildings.

You are doing this by establishing one or more Center of Trades in your country, which are mainly responsible for the production and distribution of trade goods. Further you can establish a chain of Center of Trades, each Center of Trade to another in a healthy distance to cover all your regions with goods. If you established a chain of CoTs you can also easily move rare goods around the map.
It has also potential to generate lots, i mean really lots of cash!
Besides that you wont need so many buildings anymore to make goods available. It saves building slots!

In one sentence i would describe centralized trade:
Maximize profits through pushing alot of trade only into fully developed commercial centres.

In the sense of maximizing profits by internal/external trade this region should have access to ports and be on all terrain but not mountains. It should also have provinces around which are in demand of easy trade goods( Goods you can produce fairly easy ). But it's also fine if you only got empty regions around because basic demand is easy to establish in every province. Take for example the smokehouse: it needs cattle. If you plan to establish smokehouses in a lot of your provinces theres an opportunity to get many trade deals with cattle. A very basic und easy to aquiire resource as easy as constructing the smokehouse which is a LVL 1 health building and pops up frequently.

Theres also right an example at the start of the game with a trade good which is distributed centrally, though its not an "easy" trade good.
Look at the seleucids region which produces luxury goods. All satrapies palaces of the seleucids are in need of luxury goods! By now only 4 Palaces are in range but still yet a reasonable income. Imagine how you can extend this income by increasing the commercial percentage and the trade range of other regions with Satrapy Palaces. About commercial percentage i'm talking later on.

This is the way it looks like:




- So...why ports? Trade Ports are one of those buildings that increase the commercial percentage and trade range of the region. The income by trading of a region is modified by the commercial percentage of that region! So having ports in the arsenal of a trade center is pure gold. As for example the Commercial Port boosts commercial percentage by 16% and trade range by 1, while its upgraded building Trade Port generates 30% commercial percentage! Trade ports do also provide a very good direct income to the region if you fulfill their demand for bonus trade goods ie a Trade Port can generate up to 48 gold by having Tools, Weapons, Pottery and Glass around( in its region or adjacent regions). Not only that, don't forget the direct bonus given by the buildings providing the bonus goods for the Trade Port. And these support-buildings may be in demand for bonus goods as well giving even further trading and building opportunities!


- Ok, but what it's about trade range? More trade range is good to import goods from far ahead to increase the potential to improve the region and its adjacent regions with buildings that need resources from far ahead. You can also reach your next Center of Trade if you intend to build a chain of CoTs.This may give you the opportunity to trade goods from far ahead very efficient and distribute those goods over your empire.

I made an image how a chain of CoT looks like. It describes how import/export works and what it's about "Trade Range". Note: There's no circle for the import range of Trade Center 2 for a better overview but it should be in the same size as the range of Trade Center 1. The white arrow marks the possibility to trade between the 2 Trade Centers.



- Trade range for the regions around a trade center and how to check trade range:
You also need to check how far a potential center of trade could distribute its goods to regions. This is not dependent upon the trade range of the CoT but the trade range of each region around the center of trade.
You can check each regions trade range by clicking the "Trade Details" in the buttom menu. The trade range is visualized by flashing light on the map.



- Then why no montains? Simple because you cannot build paved roads(Commercial LVL3 Building) in mountains which provide a bonus of 20% commerce percentage and +2 Trade Range. Commerce percentage is a percentage of the trade income of a region. This value is added to your total income.


- Which natural resource is suitable for a Trade Center? It is also good to have a natural resource in that province which is or will be used frequently in the future. Goods that can be exported to building chains( more on that later ) are a very good choice as there will be simply much more routes created than for goods used by only 1 building.

Another factor is what you can build in the region with the given trade good. Some very powerful trade buildings are only allowed to be build in regions with one of their bonus goods must be present in the region.
Those economy buildings are: Trading Tents(needs either Dates, Frankinense, Ivory or Silk), Trade Post(Amber, Coral, Drugs&Herbs, Furs), Trade House(Amber, Furs, Ivory, WildBeasts), Market(Leather, Dye, Cloth, Salt), Fair(Wine,OliveOil, Leather, Salt).

Of course you can provide those goods later on but it's not that bad to get early on your hands on a Trade Post with a potential of 32 gold in total or having a market there to build up a very lucrative chain of buildings early on. Also have a look at the value of the trade goods you plan to distribute!

Here's a list. Note: The number means how much money is generated by each bonus trade good a building has access to:




- What should be nearby a trade center? At best alot of provinces which are in demand of something or will be in demand soon. At the beginninig of the game check your regions resources, buildings, the actual building potential, their imports, missing trade goods and what they are in need for bonus resources. The latter isn't at first to get fast trade deals but to plan ahead which buildings and goods you need to fulfill the demand for bonus trade goods and in return what resources are needed by those bonus-trade-good-producing-buildings". This way you can plan ahead for great building chains and lots of potential for new trades.


One problem often occurs: You find that one of your regions already produce the good you want for centralized distribution by only one region. You could just remove that building producing that good but before check if the bonus of the building isn't crucial for that region/province. IE if you want to centralize cattle and you want to disable a cattle farm in your country, check if the region/province is fine with loosing the extra food given by the farm and also check if cattle is exported from there, especially to other own regions. If you demolish the building those regions may import cattle for heavy costs if you destroy the building and cut the supply for cattle.


You got a plan where you will establish a center of trade? Let's go to the next step then!

Having in mind to trade alot through this centre it's essential to boost this kind of income. You do this by increasing the commercial percentage of a region, the acumen and trade range of the region. As this region might also be heavy populated at the end, aquiring tax bonus should be a priority as well. So here's a list of buildings that boost all those values:
Remember there are important economic buildings that do need a resource present to be built.


Next to building up buildings that produce bonus trade goods for other buildings you could start producing "easy" goods in your hub that nearby regions demand to set up the first trade routes. In example you build a Salt Mine to provide existing or planned Salthouses.

I made a small list of "common goods" which im sure could be improved and extended. This list is mainly based on the more developed land at the beginning of the game but it's not far away to make use of the table and set up a lot of trade in undeveloped areas. Indeed there are some high developed goods in there as well. I put them into the list as well as an example to show what is possible in later game stages. The buildings aligned to the left in the table are more basic than on the right.


Now that you have set up one ore more trade routes, let's go to the next step!

The regions adjacent a CoT may be developed to serve the CoT by saving up building slots and to establish heavy commercial building chains around the centre.
Saving up slots for the CoT-Region by producing food and heavy infrastructure outside (while not producing new trade goods) and heavy commercial building chains following up with more infos in the next step.

For the other regions in range there's just the idea to continue developing new demand for already existing trade goods in the CoT or for trade goods planned ahead. Always having in mind to create a chain of buildings based on that trade good to maximize the profit.

Now we start rolling around masses of trade goods!

Well, lets start from the beginning. By now you got here and there some trade goods going out from your Hub into single buildings.Boring... But what if you provide one or more trade goods for bigger chains of buildings or even Uber-chains?
This is what i'm showing now and therefore I just set up an example of a bigger chain in the game and how the buildings interact with each other within the chain. By interaction i mean how they fulfill the demand for bonus goods of other buildings to even generate more income.

Ideally the chain i'm showing now can be built around a CoT but is anywhere else possible and creates alot of trading opportunities. The idea of this chain is to build main economy buildings like markets, fairs, banks and goods-PRODUCING buildings in the centre while most of the other goods-DEMANDING buildings that also provide bonus trade goods and direct income are in an adjacent region to create trade deals. Later on you get even more out of this if you build in every region markets etc to export goods like gold to banks or pottery to markets and fairs.
So here it is that simplistic image. This chain is all based around a Fair and a Market. The first level buildings contribute to the market/fair, the second level buildings contribute to activate bonus income of all the other buildings.
I also list some trade goods which could be exported by the trade hub. You do this by constructing one of the buildings importing this good. Remember to not build them inside the trade center!
I listed those buildings next to the trade good.
There are many more of those chains. This is so amazing to find out that i leave that to you.

These informations are collected out of the manual. Check it out btw, a good read!

So you wonder you are producing so much stuff but your export rate into foreign territory is very low. Now you can counter that by these measurements:

Increasing the chance to get your good get traded:
• Acumen
The higher the acumen, the more competetive are your traders in foreign nations. Acumen is a region stat which can be influenced by nation stats, events and one building. The manual states on higher Acumen: "...and will continuously snatch deals from others nations, even sometime replacing an internal trade with one of their own. "

What increases acumen:
- The building Trade Center(Tier 3/Commercial increases it by 5
- The building Great Trade Center(Tier 3/Commercial increases it GLOBALLY by 5
- The building Pleasure District( Tier 3/ Culture increases it by 3
- The wonder Petra increases it by 5


- there are also Trade Decisions to increase Acumen

• The amount of goods offered:
- the manual states: "...the more goods you have, the higher chances to have your good picked for a trade deal..."

• Co-operation Treaty and alliance
- The chance to trade is increased

• Get rid of other suppliers
- by either blockading their trade routes( blockading ports )
- or just by killing them off