Sight

Sight defines the area of the game board a unit can see and the area the unit will give to save as observations. The sight zone depends on the current weather.
All units but artilleries can only attack cells they currently see.
But be careful, within the sight area, some enemy units may not been seen because of their camouflage level.

Scouts have the "observe" action which increase their sight by 30 points, for two hours as they don't move.

In this case :

Let's make it more difficult: