The role of the army commander is to use his four corps to achieve his campaign objective.
At the start of each campaign phase each commander is sent a starter pack. This consists of a strategic map, a tactical map, an order of battle and a brief explaining the background to the campaign and the current situation. It also explains his campaign objective. This is always the capture and control of a town in the centre of the map, plus the destruction of the enemy army. It is not sufficient to just take the town, he then has to hold it until the enemy has been defeated.
He is responsible for writing daily orders for his four corps. There is a standard layout for these orders, which includes any movement, what to do if they meet with the enemy and whether they can supply.
At the end of each campaign day he receives an umpire report. This confirms his location, his casualties and his current supply state. It also warns of any enemy within ten miles (two map squares) in any direction.
Battles result when a corps enters the adjacent map square of an enemy corps. This square is called “no man’s land” and corps can only enter it if they have orders to Attack. The enemy will retreat unless they also have orders to Attack or to Hold. This ensures that neither commander is forced to fight a battle unless he has written orders to do so.
The four available corps orders are Halt, Hold, Move or Attack. Corps on Halt or Move will always avoid an enemy corps which moves into their “no man’s land” square. Those on Hold or Attack will always fight.
In addition friendly corps within marching distance will always “march to the sound of the guns” to join the battle, unless they have Hold orders or are pinned by an enemy corps.
So a commander who orders one or more of his corps to attack can never be sure that the known enemy will not be supported by other corps within supporting distance of which he is not aware.