A core is a province that is considered a rightful part of a country. Cores give several strategically important benefits:
- Provinces without a core add to overextension (except colonies), proportional to their development value.
- Core provinces get a +75% positive tax modifier.
- A country will always have a casus belli if one of their core provinces is owned by another country.
- Some missions or decisions require certain provinces to be cored
The following actions are not allowed in uncored provinces:
- Exploit development
- Moving the capital or main trading port to the province
- Culture conversion
- Recruiting non-mercenary units
- Establishing a holy order (requires a full core)
- Adding the province to the HRE
- Create a trade post
States and territories
- Main article: States and territories
States and territories are a new mechanic introduced in patch 1.16 intended to replace the old Overseas mechanic. The system introduces a 2-part coring process. A newly conquered province is considered as part of a territory (unless it already belongs to one of the nation's existing states). Turning a territory into a state requires that all owned provinces in the area be made "territorial cores" (which have a higher minimum autonomy, and are lost if the province is conquered); this costs half the base coring cost and takes the same amount of time. Once a state has been established, it is possible to instantaneously complete the coring process by paying the remaining coring costs. Administering development in states and territories costs governing capacity, which has a soft limit based on administrative technology.
Coring range is the same as colonial range, so it is often necessary to research diplomatic tech if expanding overseas without a land bridge. To check the range to a given province, change the map mode to "colonial range", and hover over the province of interest. The range will show, green for in range and red for out of range.
The following ideas and policies increase colonial range:
Diplomatic technology increases colonial range as seen here:
- If a country has a core in province A, it can core every neighboring province. A doesn't have to be owned or controlled by that country.
- If a country controls, owns and has a core in coastal province A, it can core every other coastal province that is within coring range. The ingame tooltip of requiring an "unblockaded" province is wrong, blockades do not affect this.
- If a country controls, owns and has a core in coastal province A, then it can core any province that has a "land bridge" of owned provinces to A and is within coring distance of A.
- If a country's vassal owns and has a core in province B, then the country can core any province adjacent to B in its home continent.
- If a country's colonial nation owns and has a core in province C, then the country can core any province adjacent to C in all continents.
The Holy Roman Emperor can core any province that belongs to the empire, regardless of where it is.
The base duration for coring is 36 months. All the coring-cost modifiers apply to the coring duration, except for administrative efficiency, innovativeness, and corruption. Claims apply in a different manner, as shown below.
For example, it can be reduced by the following modifiers:
- Adaptability idea −25% coring cost modifier
- Country traditions or ideas that reduce coring cost (Ottomans −20% for example)
- Choosing Shiva as personal deity of a ruler of a Hindu nation −10% (only with Wealth of Nations DLC)
- Tribal Government −5% per government rank
Note: Hostile core-creation will not apply to coring duration.
These modifiers above will stack additively.
Having a claim of any type (temporary or permanent) will give a multiplicative reduction.
- Province is claimed: −10%
A further culture bonus may be applied multiplicatively.
- Province in same culture group than primary culture: −50%
- Province has promoted culture: −25%
For example, if Ottomans with Kannunames (−20%) and Adaptability idea −25% is going to core a Greek (promoted culture) province with no claim, it will take 36 × (1 − 0.20 − 0.25) × (1 − 0.25) = 14 months to core.
Note: Coring takes a minimum of 6 months.
Coring progress will be halted if the province is occupied by hostile forces or when the current owner is at war with any country that already has a core on the province. Progress will resume as soon as these conditions are lifted.
It is not possible to core a province:
- While being at war with someone who also has a core in that province. The ongoing core creation will temporarily halt if this happens.
- While there is a missionary converting the province.
- While a building is being constructed in the province.
- While the culture of the province is being changed.
- Province is occupied (Progress halts, will resume if unoccupied).
- Province is under siege (Progress halts, will resume if siege is lifted).
Once the coring process has been started, failing the adjacency, range or land connection requirements does not revert the coring process. Coring will proceed as originally scheduled. As well, gaining or losing cost modifiers or development while coring does not change the cost originally deducted nor the coring duration originally scheduled.
Gaining cores through other means
In addition to coring newly acquired provinces manually, a nation can also gain cores by diplo-annexation of vassals or integrating a junior partner of a personal union. Both processes automatically give cores on all provinces of the acquired territory, making the strategy of "feeding" vassals with uncored provinces a viable strategy to save monarch points, especially administrative power. However, provinces cored this way begin with high local autonomy and will be relatively unproductive for some time, depending on government type.
When a colony becomes a city, its owner gains a free territorial core on it. If the owner has a colonial nation in the same colonial region (or becomes eligible for one with the colony finished), the core is instantly granted to the colonial nation instead (and ceded to it).
If a nation has completed Religious Ideas and is occuping a province of their religion which is owned by a nation of a different religion, they have a small chance of gaining the province as a core; a full core, even if the province is in a territory. If the province is owned by a Tengri nation who has syncretized its faith, the event can still fire.
Coring is an action which costs administrative monarch points. The base cost depend on the development of the province. For each point of development, the coring cost is 10 administrative monarch points.
Core-creation costs are influenced by the following:
Ideas and policies:
|Having a claim||−10%|
|Having a permanent claim||−25%|
|For the Holy Roman Emperor after the reform “Reform the Hofgericht”||−10%|
|Enacting celestial reform “Establish Lifan Yuan” (requires DLC)||−10%|
|Enacting celestial decree “Expand Palace Bureaucracy” (requires DLC)||−10%|
|Tribal Government Reform “Centralize Power” (requires DLC)||−5%|
|Adopt Land Acquisition Taxation Policy as an Indian Sultanate or Iqta (requires DLC)||−5%|
|Tribal despotism government form||−5%/−10%/−15% for duchy/kingdom/empire rank|
|Assimilating Hindustani culture as Mughal (requires DLC)||−10%|
|Choosing Shiva as personal deity of a ruler of a Hindu nation (requires Wealth of Nations DLC)||−10%|
|Choosing Odin as personal deity of a ruler of a Norse nation (requires El Dorado DLC)||−10%|
|War exhaustion||+3% per point|
|Corruption||+1% per point|
|Administrative efficiency||−1% per 1%|
|Enacting Promote Territorial Rights as a Coptic nation (requires Rights of Man DLC)||−10%|
|Enacting Reform the Bureaucracy as a Mayan nation (requires El Dorado DLC)||−20%|
|Enacting Reform the Bureaucracy as an Inti nation (requires El Dorado DLC)||−10%|
Modifiers are summed before being applied, except the modifiers from administrative efficiency and being a territory, which are applied multiplicatively after the additive modifiers are applied.
Note: The minimum coring cost for a province before applying multiplicative modifiers is 20% of its coring cost, or 2 Administrative power per development, up to 30 development. Even with a −100% modifier on a province, the cost is still 20% of the coring cost. Also the maximum coring cost is capped at 30 development for a province. This means that if the province has 31 development, its coring cost will be treated as if it only had 30 development.
The national ideas listed below increase coring costs for a province with a core from a nation which possesses this modifier. The increase applies even if the nation with the core does not exist. These modifiers are taken into account by the AI when making decisions on which nation to attack.
When negotiating a peace deal, some of the loser's cores may no longer exist afterwards:
- As mentioned above, territorial cores in a province disappear if the province changes hands.
- The loser can be forced to 'revoke their core' on any province they do not own and that is not of their primary culture (unless the victor owns that province and hasn't cored it themselves - probably a restriction to make working around hostile coring cost increases more difficult).
- If the loser is forced to 'release a nation', or 'return a core' to a third nation, their cores on all provinces not of their primary culture disappear.
- If a country is entirely destroyed, it loses all cores in provinces not of its primary culture group.
Cores in uncontrolled provinces will disappear some time after the most recent of these events:
- The owner of the core lost ownership of the province.
- A war between the current owner and the nation owning the core was fought.
The time to lose a core depends on the province's culture relative to the core:
- If the core is the primary nation for that province culture, or belongs to a nation that is a subject of the current owner, it will never expire.
- If the core shares a culture group with the province culture, the base expiration duration is 150 years, else 50 years.
- This amount of time is affected by the current owner's absolutism, scaling up to 50% reduced duration at 100 absolutism.
- Changing the culture in a province changes the length of the core decay timer. If a change to the length of the core decay timer means that the core would already have disappeared, then the core disappears.
Other ways to lose cores:
- A nation can abandon a core on a province that it doesn't own (a player can do this with a button on the province view, requires Art of War). However, this action also costs some prestige.
- When a nation sells a province, they lose both the province and core. However, this action also costs some prestige.
- When a nation releases a vassal from owned provinces, or cancels an existing subject's vassalage, they lose all cores in that subject's provinces.
A country has uncontested cores when it has cores on provinces that are owned by (part of) other countries without being at war or in a truce with those countries. They are a drain on a country's prestige: a yearly decrease of −0.1 prestige for each core province being held by another nation. Due to this prestige loss, it may be a good idea to recover such core provinces, especially if the provincial culture is already accepted in your nation.
- any province which was settled by colonization doesn't give overextension even if it is conquered by another country after the colony finished
- See in : PS_MAKE_PROVINCE_CORE = 10,
- See in : CORE_LOSE = 50 and CORE_LOSE_CULTURE_GROUP = 150