While the focus of Imperialism: Concert of Europe (ICE) is on economics, many wars were fought during the 19th century. In ICE, wars are classified based on their objective type.
Add Colony – Make a traditional minor power into a colony of your nation.
Annex Province – annex a province from another nation.
Annex Nation – annex an entire nation.
Release Nation – force a nation to release a nation that it has subjugated.
Humiliation – take Prestige from another nation.
Exploit Markets – force a major traditional nation to accept Free Trade.
If the aggressor nation wins a war, the war objective will automatically be realized.
In order to declare a war, a nation must already have a casus belli. In Dev Diary 4 we discussed the ways in which Influence tokens are used to obtain casus belli. A casus belli, in turn, is often based on possessing a claim. In Dev Diary 5, we discussed obtaining colonial claims through the Concert of Europe.
When you have a casus belli on another nation, you can declare war through the Diplomacy Panel. All of your colonies and spheres will automatically join the war on your side and all of your opponent’s colonies and spheres will join the war on their side. Your nation will be the leader of your side and the nation you declare war on will be the leader of the other side.
Depending on the nature of the war, each side will have certain provincial objectives. Objectives include the Capital provinces of all belligerents and, if the objective is to annex a province, that province is also an objective. The core objectives are the capitals of the two leader nations (and the province to be annexed, if applicable). To win a war, the aggressor must possess all core objectives and there cannot be any enemy units within its territory. The defender does not necessarily need to occupy enemy territory. It is sufficient to have one’s own territory free of enemy units after three war rounds. The war will automatically conclude once one side has satisfied its victory conditions. If the aggressor wins, the war objective will immediately be awarded.
As soon as war is declared, Fronts will be formed along the borders of nations on opposed sides of the war. Each side on a Front will have an objective. This will depend on the war objective and whether the side is the aggressor or defender in the war.
Each war round will loop through each war currently in progress. For each war, there are several phases:
- Conscript Armies. Assuming you have some worker pops that have not already been conscripted, you may conscript one or more worker pops into your military. Conscript units are like Infantry units, but are somewhat weaker, as they are not professional soldiers.
- Fleet Movement. During such a round you can Undock a docked fleet, dock an undocked fleet if it is adjacent to a friendly Port, or move a fleet to a sea region adjacent to the docks of any nation with which you are at war. Moving a fleet to a sea zone adjacent to an enemy Port province opens up a new Front.
- Sea Battles. Sea zones are grouped into sea regions. For example, all sea zones neighboring European provinces belong to the European Sea region. If there are Fleets belonging to opposing sides of the war in the region, a battle will break out. Battles will be discussed in the next Dev Diary.
- Move Armies. During this phase you can board armies onto fleets in adjacent sea zones, assign units to Fronts that can be reached by land, or retreat armies from fronts back to your Capital. When clicking on an Army present at a front, you can choose to be on the Offense or on the Defense. If you choose to go on the offense, the front will move toward your objective each time you win a Battle. if you choose to go on the Defense, the front will not move when you win a battle.
- Land Battles. Whenever a front contains armies from both sides of the war, a land battle will be played out. Battles will be discussed in the next Dev Diary.
- Offer Peace. If the Aggressor side is no longer stronger than the Defender side, the Aggressor will be given the opportunity to call off the war, resulting in an ante-bellum.
In addition to the war types mentioned above, a Great War system may be added for the late game. I have not yet decided on the specifics and it might be added post launch.
Imperialism: Concert of Europe 