This chapter describes how to move your units over the board, and what are the limitations and possibilities in doing so.
The ultimate goal in diplomacy is to conquer 18 supply centers.
There are two types of provinces, the ones that have a supply center, and the ones that do not. Every country starts with three supply centers (Russia is the exception with four). There are 12 neutral supply centers on the board (Tunis, Bulgaria, Holland, etc). All the other provinces and all seas are worth nothing when occupied.
There are only two types of units in Diplomacy: Army and Fleet. On this website, an army will be represented by a circle, and a fleet by a downward triangle.
All units can only move to an adjacent province on the map. An army can move over land and a fleet via seas or to bordering coastal provinces.
The amount of units you can have on the board equals the amount of supply centers you possess. Hence, the more territory you conquer, the more units you can build.
There are two seasons in Diplomacy: Spring, Fall. Units can only move in the Spring and the Fall. In winter you have to build (or demolish) units, so your number of units equals your supply centers.
Types of moves
A hold move is quite simple, it just means that a unit stays put in the territory (land/sea) that it is already occupying
Move means that your unit will go to an adjacent territory.
Supporting units can be done in two ways. You can either help an adjacent unit to hold its ground, or you could help a unit to move to another area.
For a support hold order. A unit offering support has to be next to the unit that will be holding. A support can be cut if the unit offering support is attack itself
The army in Ukraine tries to attack Galicia with support from Warsaw. However, the army in Rumania support hold A (Gal). as there is now a 2v2 situation, nothing will happen and both Galicia and Ukraine will not move, as the attack strength does not exceed the defense strength.
Example: . As the unit in Galicia gets no support, there is a 2v1 situation, and the Galician army is driven away. It now gets the option to retreat (after the season) and will choose to do so into Budapest.
This is the least used move on the board, but can still be quite nice. A fleet can convoy an army to a province across the water. Even if that fleet is attacked, but not dislodged, the convoy will still happen.
Conquering supply centers
In order for a supply center to become yours, you need to have it occupied with a unit in the fall of the year. Hence, if you move through a territory in the Spring, but leave in the Fall, the supply center will not become yours. Once a supply center is yours, another player can only conquer it by occupying it in the fall.
Especially new players can be very focused on doing the right moves, and also predicting the consequences of those moves. Nowadays, quite a few websites offer simulation tools (sandboxes) that could help you predict what will be the results of both your own and your opponents moves. Use this to your advantage.