Early Medieval era
Your next production goals are 3 caravans for trade (plus possibly a boat to carry them), Copernicus, Shakespeare, Library, Marketplace, and Aqueduct (not necessarily in that order).
OCC 20: Col, MP, Cop, Sha, Library, Marketplace, and Aqueduct
OCC 4: Colossus, MP, Cop, Library, Marketplace
OCC 1: MP, Copernicus, Library
Your number two tech goal is Republic. You want to switch to Republic as soon as possible. After that your tech goals are what you need to make the aforementioned production goals possible.
Often, but it depends. Sometimes terrain or AI opportunities for that map give more net results in Monarchy for a while. If the Human is able to conduct the orchestra with great effect, and this is in large part affected by the continents, the summation of the attack values of one's Hut units, the terrain surrounding the AI start locations.. then you might even get the AI to research Republic for you, and when you are ready to grow to size 8 (and hopefully 12 in quick order), you can gain the tech in concert with an Oedo year. If researching Republic, then micromanage science to just achieve the necessary beakers, and convert the rest to tax income the year before an Oedo year, and then no empire (LOL, one city) loss output occurs.
The same idea applies to Democracy, if that form of government is used.
If you have achieved Mysticism, build a temple when Shakespeare is far away. Cathedral and Coliseum should not be considered. Focus your efforts on Shakespeare instead. If you do build a temple, remember to sell it the turn before Shakespeare is completed.
That can depend on how one's supported military units are deployed under a representative government that is expected to grow via celebrations.
One common situation: While Shakespeare will prevent any
unhappy citizens, its effects are applied in
Line 5 of Happiness computation. Temples/Col/Cath is applied in Line 3, and unhappiness due to units away is line 4. If unhappiness is unchecked by Temple/C/C in line 3, it will carry through to Line 4, and this can eradicate a light blue "happy" citizen, and thus prevent achieving the 50% or more "happy" citizens necessary to celebrate, and thus grow.
Although it is a common misconception that Shakespeare and Content improvements accomplish their functions in the same way, they do not. This is most pronounced in a small empire (such as an OCC) in a smaller village with Units away and no T/C/C; maintaining units away and keeping the celebration with minimal Luxury slider settings/minimum Lux workers, can be solved cheaply with Temples. If more units away must be supported, or if in Democracy, Cathedrals and Colosseum are much more expensive long term but can do the job. Unless this considered, then either growth must be delayed, or units which are cannot be "housed" must be disbanded.
In OCC, temples will not be "free", since its not effective to build the Adam Smith wonder for one village. But for the first 2 or 3 OCC early game growth cycles, a Temple can help keep those happy citizens.
Its worth noting that in a Republic, a Police Station (which would of course be a later game option) can completely eliminate the unhappiness penalty due to units away, and thus eliminate the need for content improvements to keep the happy citizens with Shakespeare.
Finally, in large population villages, there is greater opportunity to support "unhappy" due to away (due to more content citizens on Line 4), although more and more content structures (temple, col, cath) will be required to nail the red faces once the limit of half the village population is reached. If a Line 4 redman turns a light blue to dark blue, then Line 5 Shakespeare will not restore the Happy Citizen. That means you need a tem/col/cath, or a larger base village size, to keep that Happy Citizen on line 4. In OCC, its not practical to make Hanging Gardens or Cure for Cancer to gain Line 5 Happy Citizens.
Note: the amount of Luxuries that can be applied to make Happy Citizens is capped by village size; no amount of increased Lux can make more happy dudes when the cap is hit. Two Lux will make a Redface content, and two more will make a dark blue into light bue (Content to Happy). The empire will not be large enough (in OCC) to take have other effects come into play based on government type, cities owned, or citizen total.
Another thing to do when achieving Republic is to disband some of your supported units. You should only need one unit for defense at this point
That actually depends on the strategy. For many games, no supported units are necessary by this point at all, and sometimes the exception is if there is a homebuilt (or supported, bribed trireme). No homebuilt military land units are usually necessary, unless there is a serious warlike AI threat. Until the endgame, AI can usually be contained by a caravan in a fortress on a good defense terrain like a hill. In early game, a bribed base-2 unit can be obtained from the AI or Barbarians (usually a 61g barbarian archer).
Finally, build a diplomat if you have not already. You never know when a good bribery situation may come by.
More than one can be useful for an aggressive OCC strategy. A diplomat can often go out into the field and not only return a stream of NON units, but make a significant profit on barbarian leaders. This depends partly on terrain, and how the terrain is managed. Exploiting civilized terrain gaps is often quite effective.
Democracy is your final tech goal in this era. You need to switch to it to celebrate to sizes above 21, but it is only useful if you have no units away from home and no triremes/caravels.
This is inaccurate, if you have a Temple, Colosseum, and/or Cathedral with Shakespeare (and in the right circumstances with excess food, even Shakespeare is not always necessary). You can have multiple units away from home, if you match the number content effects to the unhappiness caused by units away from home, and the village size.
If you have a lot of gold, you can buy a warrior from zero for 50 gold and then incrementally rush buy to your production goal. For example, with 125 gold you can build a caravan in one turn.
Clarification: That is 50 for the 1st 10 shields (Assumed empty shield box), and 3x25 for 30 more, meaning its assumed there are 10 shields to be used to complete the 50-shield caravan (10+30+10). An OCC-20 can sometimes generate 20 shields, pre-industrial. Then the cost goes down to just 100 gold. An OCC-4 village must make 10 or more base shields, but an OCC-1 will not make 10 in any event, though can usually be counted on for 5, which means an additional day for the caravan to complete or else paying 25 more gold and wasting the shield output that turn.
Industrial era
... or bribing one away from your rivals. If you bribe one closer to their homeland than yours, it will be unsupported and does not cost you a citizen. However, such bribery tends to be very expensive.
The NON occurs when the unit being bribed (its location) is closer its civilization's nearest city than to one of yours. In counting this, diagonals are worth 1.5 (not 1.41).
It can be expensive, though it can also be cheap. The cost of bribing a Settler/Engineer unit is double the "normal" cost of bribing a 40-shield unit. It is not uncommon for an AI to take the capital of another AI, or even for a Barbarian to take control of an AI capital; if so, then settlers will be much cheaper for two reasons: The civ will not have much gold (or at least will not be producing much new gold due to corrupted arrows), and the large constant "distance to capital". An exception occurs if the owning civ is in Democracy, since Human players can't bribe Democratic units.
As a note, I've had an OCCC-1 game in the last week were several early game settlers were less than 200g each. Those settlers created barb traps that in fact paid for themselves in making it possible to nail some more barb leaders.
Note: For info to new players, being in Democracy does not prevent the AI's Contact Bribe, and if you are aggressively using units to block or "steer" the AI units, then your individual units that are "troublesome" to the AI can (and often will) still be Contact Bribed despite your unit being in a Democracy.
When you are completely done with all transformation, irrigation, farmland creation it is time for the final round of celebrations to max size.
You can shave some lead time off of this by timing the remaining work days with the days of celebration it will take to reach the max size. If you are going from size 21 to 35, then that would take 1+14=15 days. If you have two engineers and one settler, then you can start when you have 15 days of farmland improvements to go, if you have already roaded the necessary tiles.
I have had cases when this happened when I was building space ship parts. Regardless, once you reach the maximum size, there is
usually no need to keep your aqueduct or your sewer system, but if you are carrying a supported Engineer/Settler, and want to restore that citizen to the City, then it might be good to do it before selling off the Aqua/Sewer. In later game, civs will usually have too much gold to make it economical to bribe their Engineers, even if they have no capital. But sometimes this is not the case, and you can release the supported Set/Eng and use a bribed NON for endgame, thus obtaining more science/gold with the additional worker.
If you have enough food caravans on hand for your eventual victory, and expect hostilities near the end build some defensive infra structure such as city walls, barracks, seaport, and coastal fortress.
Barracks before Mobile Warfare cost 2 gold per turn, and a Port Facility (seaport?) costs 3 gold per turn. Mobile Warfare will cause the barracks to be sold off for 40 gold, and must then be rebuilt if desired for the end of the game when you might need to defend the village. So it may be unlikely to be cost/time effective to make these city improvements this early in an OCC.
Around this time you should start paying even more attention to micromanaging your science output.
Comment: A player should ideally micromanage
all science
throughout the game in an OCC. Its a horrendous waste if a turn ends with, for instance, 2 beakers short of an advance when the SSC is producing hundreds of beakers per turn. The described micromangement technique is good, but should be a normal part of player mindset before this point in the game
.
Modern Era
Plan ahead to finish building a research lab the turn after you get Computers. This will give you an immediate 33% boost in science which is very much needed.
This would actually be a 25% boost, assuming a Library and University. That comes from 50/(100+50+50)= 0.25, or 25%. The grand city total without wonders is 100% (base) + 50% (lib) + 50% (univ) + 50% (lab) = 250 %.
Of all the choices you have for a power plant, Nuclear is by far the best. Regular power plant costs as much in shields (160) but increases rather than decrease pollution. Hydro plant costs 240 shields instead of 160 and is as clean as Nuclear. Solar plant costs 320 shields and reduces pollution the most, but it comes so late in the game (in terms of enabling technology) that for OCC it is just out of the question.
If a player have been able to obtain (make/bribe) additional Engineers and/or settlers, then one strategy is to simply have a clean up detail in late game. This effectively makes the PI's irrelevant, and in practice a rule of thumb is that a Pollution Skull will occur every 2nd turn on average, but no more than one skull can occur per turn. So the question in an OCC-20 is the balance of resources and build turns in removal or prevention.
I often use these to pre-charge in fortresses, and then even a settler can zip out to the white skull and in one turn, zap it with the precharge. Two settlers or one engineer can usually handle the pollution. If so, then a power plant can be obtained earliest and need not be replaced with a nuclear plant (which could melt down in any event). Hydro plants cannot be built in all locations. But both Nuclear and Hydro do take more resources and occupy production days of a village. If for some reason no Power Plant were built earlier, and the additional output were needed after Nuclear Plants were available, then I too would build Nuclear.
Once consideration is to get to 84+ shields by the time structurals are ready to build (for an OCC-20 SS), though there are different shield combinations, even down to the OCC-1 SS.
Flight
You want to delay Flight as much as possible because it makes Colossus obsolete.
The other reason is that the trade bonus is lowered from 66% (Post-RR) to 33% (Post-Flight), which means the same freight delivery will collect less science and less gold after flight. You want to deliver them at higher value, and apply that science to things you need before flight.
Meanwhile avoid contact with your rivals. They are likely to cancel alliances at this point in the game or start wars if you do not share what they want with them. You should avoid giving them ...
If the tech you need is done and you've sold your science improvements, you can also consider a change of governments.
Normally, players should long before have been able to make fortresses within 3 tiles of the city (Democratic happiness), as well as fortresses at chokepoints which are occupied by Freight on NONs or charging Engineers/Settlers & sometimes dip/spy. The RR going thru each of these allows a shift of any unit to any location, and wounded to heal.
One can also make hills under key fortresses, to add 100% to their defense value. This way a non-vet Mech Inf defends with 18. If you can make the hill fortress on a river, then its 21. If its also Vet, then 24.
If you are surrounded by multiple rivals also add an airport, seaport, and coastal fortress.
If AI trade partners have an airport, then you should already have one also, for the bonuses (except would be if you have a qualified RR connection). Seaport is maybe Port Facility? If you have no navy, Port Facility is not necessary. Or if you are trying to make vet stealth fighters, its not worth occupying a game turn and expense. Coastal Fortresses still cost 1g per turn, so its good to know how and when Naval units bombard.
Disband all your ancient supported units and replace them with modern vet units.
Supported Ancient should long be gone; as a minimum if there are supported military land units, those
should have been converted to Riflemen or Alpine already. As the SS is completed, Mech Inf and Stealth are good, but disbanding is probably not the best idea (
unless money is tight and that a supported unit causes a shield of support that drops output below a common multiple like 40 or 50). The quantity of meat shield in fortresses will reduce/slow/stop an invasion. Just make the intended modern unit; if the village has an output of 50 shields, then that is a Vet Mech Inf every turn. For Stealth + a 50 shield village, just RB a Temple (160g), change to spy, add one line of 10 shields (25g), and switch to stealth. For OCC-4 (where you have 20 shields output), the same formula works to make a Mech Inf instead of stealth, and 30 more shields (3x25=75) for 75 more gold will make a Stealth.
Build fortresses in your city perimeter and put at least one unit in each even if it is a van.
If the unit is expected to meet enemy units which want to get through, then the AI will not bribe a Freight, but can Contact Bribe a lone military unit, so use a good defense unit doubled up with a dip/spy, a freight/caravan, a weak or damaged unit, or "old" unit.
and shield specials (iron, peat, …
