one dataset · paper, tables, graph, wiki
simgrammar the grammar of simulation

parts

21 mechanics, as Europa Universalis IV does them

core · 5

social relations

Faction diplomacy

Alliances, vassals, tributaries, and royal marriages bind nations; aggressive expansion raises other nations' hostility until they form a defensive coalition against the expander.

governance & policy

Political capital

Administrative, diplomatic, and military monarch points accrue monthly from the ruler's skills (plus advisors) and buy technology, ideas, stability, and province development, so each succession changes the nation's budget of action.

governance & policy

Stability and unrest

Provinces accumulate unrest from foreign culture, religion, and recent conquest, and high unrest spawns rebel armies; national stability is a separate stock raised with administrative monarch points.

conflict & defense

Territorial control

Provinces have an owner and a controller; sieges flip control, peace deals transfer ownership, and new provinces must be cored with administrative power, with uncored land adding overextension and unrest.

economy & finance

Trade routes

Trade value generated in provinces flows downstream through a fixed directed network of trade nodes; merchants either collect in a node or steer value toward the player's home node, and trade power in each node sets the share taken.

supporting · 16

information & legibility

Causal breakdown tooltips

governance & policy

Corruption leakage

A national corruption value accumulates from several state conditions and falls with a monthly budget line for rooting out corruption; while high it raises the cost of technology and other state actions.

population & lineage

Culture and religion conversion

Provinces have a culture and a religion; missionaries convert province religion over time against resistance, and non-state religion or non-accepted culture adds unrest.

population & lineage

Dynasty succession

Each monarch's administrative, diplomatic, and military skill sets monthly monarch point income; on death an heir succeeds, with risks of regency, succession wars, or personal unions.

information & legibility

Fog of war

governance & policy

Interest groups

Estates hold loyalty and influence over the crown and grant bonuses or demands.

economy & finance

Loans and debt

Deficits are covered by loans, and unmanageable debt ends in bankruptcy.

multiplayer & persistence

Modding API

Script and data files define events, countries, and rules; total conversions replace the setting.

social relations

Opinion modifiers

AI opinion of the player is an itemized sum of modifiers such as improved relations, royal marriage, and aggressive expansion.

governance & policy

Policy toggles

Idea groups, policies, and government reforms change national rules.

social relations

Reputation

Prestige and power projection modify diplomacy and stability.

conflict & defense

Statistical combat resolution

Land battles roll dice each phase of fire and shock, modified by general skill and terrain, and drain each army's strength and morale until one side retreats.

progression & goals

Tech tree

Administrative, diplomatic, and military technology tracks are bought with matching monarch points; institutions such as feudalism spread between provinces and raise technology cost until embraced.

narrative & generation

Triggered event chains

Historical and flavor events fire from national history and current state.

conflict & defense

War score and peace terms

War score from battles, occupation, and the war goal caps peace demands, each priced in score (provinces, gold, vassalage).

core loop

accrue administrative, diplomatic, and military monarch points -> buy technology, stability, ideas, and development -> steer trade and colonize -> ally and declare wars -> occupy and annex provinces -> manage unrest, estates, and coalitions

design notes

EU4 converts ruler quality into three spendable currencies (administrative, diplomatic, and military monarch points) that buy technology, stability, ideas, and province development, which makes each succession an economic event. Expansion is checked by systems rather than scripts: aggressive expansion feeds defensive coalitions, and conquered provinces stay restless until integrated. Monarch points, war score, province integration, and missionary conversion are not yet mechanics in the taxonomy (proposals political-capital, war-score-peace, territorial-claims-integration, culture-religion-conversion).

appears in

the paper, 3 sections · 3 chapters · 2 episodes
paper

3. The catalog

linked in this section of the paper

paper
paper

5. The structure of the design space

linked in this section of the paper

paper
paper

Appendix A. Game catalog

linked in this section of the paper

paper
catalog

The catalog

listed with its year, developer, subgenre, and number of mechanics

book
ch 3

Chapter 3. Old parts

linked from the text

book
ch 4

Chapter 4. Families

linked from the text

book
ch 5
book
ep 2

Where the parts came from

on screen at 1:32 a date is a lower bound

episode
ep 3

Families across genres

on screen at 3:38 odd couples, 5:55 the sequel that moved

episode

sources

1
Wikipedia contributors (2026). Europa Universalis IV. Wikipedia

provenance

runs in log/runs
2026-10-24
created2026-10-24-catalog-gicatalog
2026-10-25
reviewed2026-10-25-contributor-readinessmaintenance