META GEOPOLITICS for dummies

This is a basic guide of principles of geopolitics for CK3: where to put your capitals and what counties are the best to hold in your personal domain and develop. Probably skip if you're a roleplayer who doesn't want meta spoiled.

I actually have an updated version that goes further in deep, but it didn't get much attention. If you liked this one, visit this as well, maybe you'll find more interesting information: https://steamcommunity.com/sharedfiles/filedetails/?id=2981200762

The basic principles of geography exploitation

So, you've played a few campaigns and you're interested how to optimise your gameplay. This section will help you to understand the fundamental rules of geography location in CK3.

GEOGRAPHY MATTERS

The first step to optimise your gameplay is to understand the core mechanics. The game could be divided into several basic systems of different volatility that are stacked on each other in the order from the most to the least volatile assets: leaders, nations, land.
Leaders are the characters that you will play as or that will accompany you throughout your journey. Generally, depending on your dynasty management skill and some luck they will change each other every 30 to 50 years. While their skills will define the rate of success of your interactions with the world, they are mere frail and mortal humans after all, so you should be prepared with a strong base that even the most unfit ruler would use effectively.
By nations here i mean religions and cultures that you will encounter across the world. Religions define your immediate diplomatic situation, since NPC rulers tend to base their policy around the borders of spiritual domains: brothers in faith tend to intermarry with each other and thus form alliances, while the further astray they see a faith, the more hostile to it they become. Additionally, some religions have bonuses/debuffs to leader traits and to geography. Cultures are quite similar to reiligion in the sense of their effects, but with lesser effects on diplomacy (no one will attack you just for having a different language or heritage, but it will lower their opinion of you a bit) and with bigger effects on the bonuses. Both religions and cultures are highly customizable, but they have little to no RNG (unlike genetics and education of the characters) and that they shouldn't be changed at all or changed as rare as possible (however, most of the times you will need to hybridize or diverge a culture and create the best religion at least once in a campaign, but you'll have to be prepared for massive conversion campaigns and some unrest as the result of that).
And finally, the land. Most of the important aspects of it are hardcoded in the game, so you won't be able to change it by gameplay. Land is divided into counties that are gonna be the base of your interaction with the map with less significant subparts in form of baronies. Counties are always a part of de-jure duchies, which are a part of de-jure kingdoms, which are a part of de-jure empires. The land is also divided into personal domain and vassal domain: personal domain is whatever land that you control personally, meaning that you will get 100% of benefits from it, but you will also have to invest in it alone; vassal domains are a property of your vassals, so you don't get full benefits of it, but just a small cut of whatever vassal is getting, but at least you don't need to invest into it. Since feudalism means internal conflict, you are participating in the constant arms race with your neighbors and your vassals, that's why having wealthy personal domain is so important. Every barony in game has a terrain assigned to it. And this is where ck3, IMO, is drastically different from its predcessor. In ck2 it was hard, but not impossible to play in Arctic Russia (look in my profile for a screenshot of 7 slot county of Kolguyev that i achieved by strategic investements), Steppes, Mountains and other regions considered less inhabitable by our human kind. In ck3, however, you are gonna encounter the glass ceiling of limited building chains — yes, you can invest into a mountain barony, but it will never be as good as one in farmlands or floodplains. And here where the secret is: IT IS ALWAYS BETTER TO HAVE FARMLANDS AND FLOODPLAINS AS YOUR BASE. Because ck3 is a game about realistic historical geography, and not a fantasy or sci-fi world where we can terraform everything we want to, we are quite limited in the choice of regions that are the most optimal for gameplay.
TL;DR Place your personal domain in farms and floodplains region and develop them!

The strive for developement

How useful a personal domain is, will be defined by several factors in the order of their effect:

Terrain

Every barony has a specific terrain assigned to it. You can find the list of all the terrains on Ck3 wiki. Terrains largely define how useful the barony is to hold. While supply limit, movement speed and combat width affect the armies going through it, the most important part is the bonus/debuff to developement growth. Every county has a number of developement assigned to it from the start, but during gameplay this number can change: the bigger the amount of developement, the more armies and more money you get from owning it. That's why it is so important to constantly have a steward on the mission to develop the lands (until you hit the tech cap) and that's why it is important to maximize the efficiency of it. Both farmlands and floodplains grant you +20% to developement growth, while plains (probably, the most common type of terrain) do not grant you any bonuses, and steppes, deserts and desert mountains cripple you with -50% to developement growth.

Building chains

The barony with a basic holding won't provide you with a lot of resources (mainly, men to muster them into armies and money to pay for the armies), that's why you need to constantly invest in them to build holdings that, surprise, are highly dependant on a terrain type of a barony. Generally, you want to focus more on making money, because it will allow you to get the best men-at-arms, not go bankrupt for raising an army (otherwise you will practically debilitate your troops) and hire mercenaries in case you need more troops. That's why personally i build three money buildings with one specific building to buff a specific men-at-arms type. And can you guess what terrains give you the best buildings? FARMLANDS AND FLOODPLAINS on coasts.
Coastal holdings will give you an access to tradeports that give you both money and developement growth.
Farmlands give you Farms&Fields that give you the most amount of money and developement growth compared to forests and hills, Manor Houses that will give you an enourmous amount of money, and Barracks that will give you bonuses to heavy infantry (i just like them more than the other men-at-arms types). But farmlands are also rare and generally come in small patches among other terrains.
Floodplains give you Orchards that grant you a medium amount of money, developement and some levies, but floodplains are also more common and they are less spread out than Farmlands.
If you can't find a proper coastal farmland or floodplain, then plains, forests, deserts (only with desert dwellers cultural trait), taiga (only with forest wardens cultural trait) or hills (mountaineer ruralism) would suffice. But never, under any circumstances, don't put your trust in jungles, steppes, deserts or desert mountains.

How-to

If you decide to optimise the geography, you need to choose a location first and focus your early game on conquering and consolidating it. Don't spread out too much, try to concentrate it. After initial conquest focus your characters on Stewardship and Education: Stewadship will allow you to get a lot of money and upgrade buildings cheaper (even without geography, you should be constantly building something) while Education will give you easier time raising the actual developement of provinces. Also consider that sooner or later you will hit a ceiling in form of techs: you can't build a lot of upgrades, special buildings and duchy capital buildings without proper techs and your developement growth will be practically zero after you hit the maximum amount allowed by your tech. So try to follow the next strategy: first two rulers conquer and consolidate the wanted provinces, then you spend one or two generations by just hoarding money and spending it on upgrades, then you spend one or two generations investing heavily in techs, then upgrades, then techs and so on. Don't forget how culture can affect the meta by specific culture traits turning previously weak terrain into managable one or getting even more bonuses to overpowered terrains. Religion affects developement less, just avoid "sanctity of nature" trait and try to get a religion with holy sites in your domain — that way you can get a powerful special building.

Additional notes

As it was previously said, some of the debuffs could be turned into buffs with special cultural traits, but then again, nothing can beat agrarian culture trait in farmlands in terms of raw developement output. Then you have to look into county capacity: every county has a certain amount of baronies that it can hold and obviosly, the more the merrier. You should focus on building your counties to the max — with castles as additional source of troops and money in your personal domain and with cities and churches for more developement. There is also a benefit of special buildings and duchy capital buildings: special buildings (mines, holy sites, universities and important forts) and duchy capitals are hardcoded in the game, so you can't change their place, but the bonuses they give can turn an insignificant province in powerhouse.

The optimal regions

IMO with reasoning listed above and below these five regions are the most optimal regions to play in.

Lower Rhein + Denmark

The main reasons for this choise are six somewhat close to each other farmlands, four of which are coastal and five of which are duchy capitals (Holland, Flanders, Zealand, Skane, Cologne). Plus Scane and Cologne have special buildings. This could be a good base of a viking with dutch hybrid culture (to get the maximum bonus from coastal holdings from Maritime Merchants culture trait and farmlands from Agrarian culture trait), and it is somewhat historical!

Mediterranean

This region could be divided in two subregions of Iberia and Southern Apennine peninsula. Starting with Iberia: three farms that are fairly close to each other all of whom are duchy capitals (Cordoba, Sevilla and Toledo) with special buildings in Cordoba (this one is practically enough to get you through the early game, even if you start as OPM) and a university in Madrid. Generally, if i play in this region, i get an addition of Galicia duchy, since Coruna and Santiago have wonderful special buildings that will be of great use to Christians uniting Iberia.

Southern Apennine have four coastal farmlands, three of which are duchy capitals (Latium, Sicily, Salerno), two special buldings in Rome alone, one in Palermo and a silver mine in the plains of Cagiliari. Very powerful position, but you would likely have to leave Rome to Pope, unless you want to see a crusade every few decades.

Eastern Mediterranean

This region could also be divided into two subregions of Egypt and Mesopotamia. Egypt has plenty of floodplains provinces, but only one of them is coastal. If you go further up the Nile river, you can find plenty of duchy capitals in floodplains and with Agrarian culture trait of egyptian culture you will easily become the most advanced nation in the world. But you won't see many special buildings.

Mesopotamia has plenty of concentrated floodplains with three special buildings and five duchy titles.

Western Africa

The best region to play in Western Africa is Niger river floodplains, however it is heavily limited by only two duchy capitals and divided nature. Three gold mines are making it pretty good.

India

Arguably, the best region overall. Huge chunks of overpowered farmlands concentrated close to each other, thirteen duchy capitals in total (two in Tamil kingdom, two in Punjab, four in Delhi and five in Bengal), plus isolated ones in Orissa, Burma and Malwa. Add enormous amount of starting developement (on the same level with Constantinople) and you get the personal domain so powerful that you barely need vassals.

Conclusion

This rundown is supposed to give you the basics of meta play of CK3. But be aware that CK3 is not a game that you should want to play optimally — it will quickly suck out all the fun out of it. Sometimes you need to lose to get a cool story of a comeback, sometimes you want to roleplay an isolationist mountain dweller nation and sometimes you just want to relax by genоciding painting the map and bringing the civilization or just raid. However, i'd advise ck3 enthusiasts to try pure meta at least once just to see how quckly you can become the most powerful empires by personal domain only.

[Poompaxhotl-Mardxvar]

I actually have an updated version that goes further in deep, but it didn't get much attention. If you liked this one, visit this as well, maybe you'll find more interesting information: https://steamcommunity.com/sharedfiles/filedetails/?id=2981200762

[grownnsexy0427]

Thank you so much for this I have been playing a while and I have been searching for information to understand these concepts of the game. This was an excellent overview!!!

[Panda BaoBao PL]

I invite you to my ultimate guide about millitary
https://steamcommunity.com/sharedfiles/filedetails/?id=2846475771

[Gwalarn]

Well done, I wanted to go back to this game and you helped me a lot !

[Amumununu]

Nice guide. Informative and focused. Appreciate your write-up, definitely not a game system I knew of or would have ever even thought to pay attention to.