trigger · is_core_of

Hands-On Usage

is_core_of is commonly used to check whether a state belongs to a specific country's core territory, and frequently appears in scenarios involving territorial claims, peace negotiations, and decision availability. For example, in "reclaim territory" type decisions, you can check whether the target state is a core of your nation to determine whether to allow the decision to be triggered; you can also use it in a focus tree's available block to confirm that the target territory has become a core before unlocking certain national focus rewards.

# Example: this decision is only available when the target state is a core of your nation
available = {
    any_neighbor_state = {
        is_core_of = ROOT
        is_owned_by = FROM
    }
}

Synergy

• [is_owned_by](/wiki/trigger/is_owned_by): typically used together with is_core_of to distinguish between "nominal cores" and "actual control"—for example, confirming that a state is both your core and occupied by an enemy to trigger specific events.
• [is_claimed_by](/wiki/trigger/is_claimed_by): used in contrast with is_core_of to differentiate between "sovereignty claims" (claim) and "core territory" (core) as two different tiers of territorial demands, avoiding condition confusion.
• [add_core_of](/wiki/effect/add_core_of): commonly used as a follow-up operation when is_core_of evaluates to false—first check whether it is already a core, and if not, add it via this effect to prevent duplicate additions.
• [remove_core_of](/wiki/effect/remove_core_of): paired with is_core_of for guard checks to ensure removal only occurs when the core actually exists, avoiding invalid calls that could cause logic errors.

Common Pitfalls

1. Scope confusion: is_core_of must be used under STATE scope. Beginners often make the mistake of writing it directly in event options or focus reward blocks under COUNTRY scope, causing script errors or conditions that never trigger. You must first switch to state scope using methods like any_neighbor_state, state =, etc., before calling it.
2. Target and subject reversal: the semantics of this trigger are "this state is a core of <target>". Many beginners mistakenly think writing is_core_of = GER means "GER is a core of this state", but the actual meaning is correct. However, when you want to express "my nation owns a core of this state", you should use pronouns like ROOT/THIS rather than hardcoding a country tag, otherwise the logic will completely fail when another nation uses this script.