start_wars_for_mongolia_effect

start_wars_for_mongolia_effect = {
	save_temporary_scope_as = mongol_conqueror
	# Build a list of potential targets
	every_neighboring_top_liege_realm_owner = {
		limit = {
			any_sub_realm_county = {
				is_landless_type_title = no
				title_province = { geographical_region = special_mongol_empire_start_region }
			}
			is_landed = yes
		}
		if = {
			limit = { NOT = { is_in_list = top_liege_targets } }
			add_to_temporary_list = top_liege_targets
		}
	}
	every_in_list = {
		list = top_liege_targets
		if = {
			limit = {
				government_has_flag = government_is_herder
			}
			create_title_and_vassal_change = {
				type = swear_fealty
				save_scope_as = change
				add_claim_on_loss = no
			}
			change_liege = {
				liege = scope:mongol_conqueror
				change = scope:change
			}
			resolve_title_and_vassal_change = scope:change
		}
		else = {
			save_temporary_scope_as = new_war_target
			capital_county.empire = { save_temporary_scope_as = war_target_title }
			# Declare the war
			scope:mongol_conqueror = {
				start_war = {
					cb = mongol_realm_invasion_war
					target = scope:new_war_target.top_liege
					target_title = scope:war_target_title
				}
			}
		}
	}
}

As written in game/common/scripted_effects/00_mongol_invasion_effects.txt.