Social Policy: Commerce (G&K)

Introduction

Commerce becomes available in the Medieval Era and is focused on the economic side of the game. As a full tree it can benefit any Civilization when there are coastal areas and plenty of water, or indeed any situation in which you have high food/gold but low production tiles. It can give you extra movement for your ships, production for your cities, cheaper trade routes, increased gold for your capital and better luxury value. Upon inspection, Commerce is divided into two distinct strands: one focusing on the the naval aspects of the game, and the other on reducing costs and improving gold and luxury values.

Regardless of whether you go for a full or partial Commerce tree, Commerce in general is something that benefits all kinds of civilizations and the strategies you are going to use. The benefit of Commerce is primarily a stronger economy which can be used in whatever way you desire.

The Policies

• Commerce
• Naval Tradition
• Merchant Navy
• Trade Unions
• Mercantilism
• Protectionism
• Finisher

Strategy

• General Strategies

The Policies

Commerce

Adopting Commerce will boost Gold output in Capital City by 25%. May purchase Great Merchants with Faith.

Opening the commerce tree increases the Capital's gold output by 25%, stacking additively with markets and other percent modifiers. Any start with a high gold output capital position can see some very nice returns from opening Commerce. Anything that boosts the Capital's raw gold output such as building the Colossus or National Treasury increases the benefit of the opener. A tall empire, particularly one that has developed the Tradition tree, can really capitalize on this with relatively more gain than a wide empire. If running a very tall capital strategy, this policy is the only way to boost gold % modifiers over 100% (Opener+Market+Bank+Stock Exchange) which can make the free gold from Monarchy and the Commerce Finisher go much further.

Great Merchants bought by faith could be used to build a Customs House near the capital, since it could enjoy the 25% bonus.

Naval Tradition

+1 Movement for Naval units and +1 Sight for Naval combat units. A Great Admiral appears. +2 Movements for all Great Admirals.

Naval Tradition is the starting policy pick for the left hand side of the Commerce tree, and it is the only social policy in the game that directly enhances naval units (both ships and embarked units). An extra movement for all naval units, especially embarked units, is quite helpful. To put this in context, the bonus from Naval Tradition is about half of England's or Denmark's (DLC) Unique Ability, which have +2 Naval movement, and +1 Naval movement (and some other things) respectively. Additionally, Commerce grants a free Great Admiral and adds 2 movements to all Great Admirals. Since Commerce is unlocked in Medieval Era, the free Admiral will be something that most other civs don't have, which means Naval Tradition is also your incentive to play aggressively in navy. Adding up the 2 movements, each of your Great Admirals will have 6 movements. This could let them follow the pace of your warships.

Moreover, since Admirals are not restricted to coasts, you could use it to explore the ocean without teching Astronomy. By exploring early, you could find new city-states, which bring 15 or 30 , new civilizations, which bring profitable trades, and new Natural Wonders, which bring happiness. However, you need to be very careful when using the Admiral because it can be easily killed by barb naval units. Better ensure that the Admiral stays in deep ocean at the end of each turn.

Naval Tradition is stronger than the Great Lighthouse, as its movement bonus affects embarked units as well as ships. Naval Tradition is easily the strongest policy for a navy of any Civilization. If you were to combine Naval Tradition with the Great Lighthouse your navy would receive +2 movement and +2 sight to all naval ships. For two policies (Opener+Naval Tradition) and a wonder you can nearly gain the equivalent of England's unique ability, with more +sight but less +movement for embarked units.

On that note, England, Denmark, Polynesia, Ottomans, Spain and Carthage will want to pick this (and most other policies in Commerce branch) to help increase their natural advantage on appropriate maps.

Merchant Navy

+3 Production in all coastal Cities.
Requires: Naval Tradition

This is the biggest per-city production boost for a city from any social policy pick, although it is limited to coastal cities. Merchant Navy is one of the strongest policies in the entire Commerce tree on appropriate maps. An extra three production per city provided it is coastal, especially for a wide empire on a water map, can be quite a substantial boost. It is especially valuable to those who desire coastal expansion, because adding up the production from Republic, each new city will get 5-6 just from the city tile, making it developing up very fast.

Trade Unions

Maintenance paid on Roads and Railroads reduced by 33%. Harbors and Seaports gain +1 Gold.

Trade Unions is the first pick on the right hand side of the Commerce tree and is focused on the generation of gold. Trade Unions cuts road and railroad maintenance by a third, while harbors and seaports gain one . Again, the focus on coastal cities is clear and the harbour/seaport boost alone represents a tidy bonus. But it is extremely valuable to Carthage, who gets a free Harbor in every city, which could bring forward an additional gold per city.

The reduction in road and railroad maintenance costs, however, can save a substantial amount of GPT. The reduction for the road is not that significant, but for even a basic railroad network connecting coastal cities can be quite powerful. A simple six hex railroad will have its maintenance reduced from 12 GPT to 8 GPT. The saving is small, but can mount up if the rail or road network is large enough. This makes it ideal for Pangaea or Continents maps, where Civilizations typically have relatively large road and rail networks. More information on the benefits of this can be found in the trade route guide.

Mixing Trade Unions with Meritocracy from Liberty can be a strong combination. This means that normally you will get the +1 from Meritocracy with no net loss of gold with a two population city, so you can start trade routes earlier. This allows future expansion to occur earlier and every citizen above 2 in the new city will generate gold.

Mercantilism

Purchasing items in Cities requires 25% less Gold. +1 Science from every Mint, Market, Bank and Stock Exchange.
Requires: Trade Unions

This is one of the best, if not the best, social policy in the entire Commerce tree. This stacks additively with Big Ben's 15% reduction for a total of 40% reduction, and multiplicatively with Militarism's 33% unit price reduction for a near 50% reduction for units, or a 60% reduction on units with all three together. The utility of this Social Policy becomes more obvious the more you rush buy units or buildings. The benefits from Mercantilism tend to be reduced with the advent of factories, railroads and power plants as production is boosted, but the benefit can still be quite substantial especially if your GPT is higher in comparison to your production, a difference which is amplified by the reduced gold/hammer ratio in the late game. The science bonus from relevant financial buildings is a small bonus, but it further encourages you to give priorities to financial buildings, which means you will emphasize on gold and use the reduction from this policy to rush buy. More detail on how to use this can be found in the general strategies section.

Protectionism

+2 Happiness from each Luxury resource.
Requires: Mercantilism

With 2 extra from each type of luxury resource, Protectionism is one of the best happiness policies in civ 5. The policy is dependent on existing luxury goods so a wide empire will, in most circumstances, benefit more than a tall one will, although a strong city-state focus will often make up the difference between the two. At most Protectionism will give you an extra +44 and this is only true if you are on a map of large size or greater as smaller maps will often not have all of the unique luxuries available. In practice (considering map size/diplomatic situation etc) it will probably yield something about +20.

One way to look at Protectionism is that it is a doubled Notre Dame as a social policy, but with a higher opportunity cost. To take Protectionism you need to invest four social policy picks (Opener - Trade Unions - Mercantilism - Protectionism) which may be a lot to ask from a wide empire, although a tall one could take more benefit from it.

That said, a wide empire with a significant road or rail network and a strong gold producing capital can benefit reasonably substantially from this line of social policies. Much more so than a tall empire would, which typically do not have a large enough road or rail network to gain much from Trade Unions.

Finisher

Adopting all Policies in the Commerce tree will grant +1 Gold from every Trading Post and doubled Gold from Great Merchant trade missions.

Commerce finisher calls you to put even more emphasize on gold, thus have synergy with other policies in Commerce branch. With Commerce finisher and Economics, each trading post will be providing 3 gold per turn. That means you could consider building more Trading Posts, rather than Farms. The trade-off is essentially, 3 gold vs. 2 food. Another part of Commerce increase the value of Great Merchant, by providing doubled gold from trade missions. This bonus makes working Merchant specialist slots more profitable because the Great Merchant will be able to get over one thousand gold and 30 relationship points from City-States.

To sum up, the finisher is able to provide a lot of gold that would be invested in cities, armies, whatever. The first part of it encourages players to replace Farms with Trading Posts, while the second part suggests working Merchant specialist slots, instead of GE, GS etc.

General Strategies

In general, Commerce benefits coastal, gold-producing cities and it is a balanced policy tree. Each policy has synergy with another. The opener gives gold bonus directly. Naval Tradition benefits naval units, from movement, sight to combat bonus (free Admiral), while Merchant Navy provides big advantage to coastal cities. On the right side, Trade Union isn't good enough when compared to other policies, but it encourages players to build a wide empire, which matches other policies around. Mercantilism emphasizes producing gold and adds benefits to financial buildings, while Protectionism gives happiness bonus, which is an extremely huge benefit to a wide empire. Meanwhile, the finisher further increases GPT.

The extra +3 from Merchant Navy does require the slightly weaker Naval Tradition, but it can add some much needed production to your coastal cities. The 25% discount from Mercantilism is good regardless of map and if social policies aren't part of your victory conditions, then taking Trade Unions and then Mercantilism can save quite a bit of gold for you. Combining Mercantilism with Big Ben gives you a total of 40% off of any purchases, which can make buying units and buildings ridiculously cheap.

Since most policies in Commerce tree are mutually beneficial and the finisher is pretty good, trying to adopt all policies in Commerce branch is generally a feasible plan.

The Commerce sweetest spots: Archipelago and Large Islands

There are certain maps where Commerce will be a key policy tree that far surpasses others. They are Archipelago and Large Islands.

The reason for this is that an isolated island/small continent start on a standard map can potentially yield 6-9 coastal cities with few hexes wasted due to overlap or lack of reach. All of your cities being coastal is important to get the most out of Merchant Navy. Plus, production is usually poor in Archipelago maps. A lot of water is required for the most advantage to come from Naval Tradition. A reasonably sized road/rail network is the best compromise between the right and left sides of the tree. Mercantilism will work well as you will be pursuing gold in Island maps, not production. The extra from luxury resources helps found a wide empire when Astronomy is researched. Trading Posts will also be incredibly useful because Farm will not be a good improvement in most Island maps since your food source mainly comes from the sea.

Maximising Commerce: Rushbuying vs. Production
To buy or to produce? That is the question.

As the entire tree (with exception of Naval Tradition) is related to boosting your net economic gain either by reducing costs, increasing gold production or increasing production output, a brief word on the shift from production to gold in terms of the most cost efficient way of producing items is warranted.

The rush buying formula features the production cost of units taken to an exponent less than one, which results in more expensive hammer cost items costing relatively less gold. Take two units: a Warrior and a Nuclear Missile. On standard speed the warrior costs 200 gold or 40 production and the nuclear missile costs 2270 gold or 1000 production. If you calculate the gold per production, the warrior is more expensive to buy (5 gold/production) making it more efficient to build than buy. The nuclear missile, however, is relatively cheaper (2.27 gold/production) and so is more efficient to purchase. The conclusion to be drawn, therefore, is that it is more efficient to purchase items in later eras than it is in earlier ones.

The advantage in purchasing these units is, however, greater when Mercantilism (-25% cost of purchase) and Big Ben (an additional -15% cost of purchase) are factored in. The nuclear missile costs 60% of base, from 2270 gold to 1360 gold with both Mercantilism and Big Ben. Its production cost remains static at 1000. This means that rushing buying a nuclear missile costs only 1.36 gold per hammer, the best gold to hammer ratio purchase in the game.



Note: Amended from vanilla Commerce by Veneke, this article is in G&K version.

The particulars of rush-buying units and buildings are covered in more depth here, including the penalty costs for rush-buying units and buildings in the pre-Renaissance eras.