"All warfare is based on deception."
–Sun Tzu, The Art of War
In most cases, armies travel in the open, with little effort at stealth. As a result, detection of enemy armies is considered to be automatic for any enemy armies that are in the same hex. However, armies can bivouac under cover to hide their presence, and by moving at half speed they can remain largely out of sight. Note that if an army would already be moving at only 1 hex per day, it must use a forced march (see Forced March) to continue moving at 1 hex per day while using camouflage.
An army that detects another army, either through scouting or being in the same hex, learns the other army's number of soldiers, creature composition of its units, and which adjacent hex they are heading towards if they are moving.
Scout Check: To scout for enemy armies, the army commander can assign one of his units to scout hexes. The scouting unit's leader substitutes Profession (soldier) with Survival to determine a special Leadership Bonus for scout checks known as LB (scout). The area scouted is centered on the army. A Scout check is made when a unit is assigned to scout or when the army moves into a hex. As long as the same unit continues to scout, the army commander's knowledge of the scouted area is updated every two hours. The commander can order the scout unit to perform a new Scout check at any time. If no unit is assigned to scout, the army can only scout the hex it is in, and the Scout check uses the army commander's LB (scout). A scouting unit moves at half of its speed.
Scouting Modifier: A unit's Scouting modifier is equal to 1/4 of the scouting unit's Perception modifier, plus the LB (scout) of its leader. To notice another moving army that is using camouflage, an army rolls 1d20 and adds its Scouting modifier against a DC equal to the enemy army’s base Camouflage score.
One of the army's units can be devoted to scouting a number of hexes away from the army depending on its size. Scouting units allow the army commander to know the position of any other army within the scouts' range. If the other army is using camouflage, then the unit's leader must make the Scout check to detect the other army. Aside from using camouflage, an army may also avoid detection by eliminating the opposing army's scouts. The army commander must make an LB check against the scout leader's Scout check. If the commander's check beats the Scout check, then the scouts in the army's hex are killed, and the scout unit takes 1 damage. If the commander's check exceeds the scout leader's check by 5 or more, the army remains undetected; otherwise the scouts are still killed, but the scout leader immediately learns of their loss. The army is detected if the scout leader's check beats the commander's check. When either army moves to another hex, the army commander must make another opposed LB check against the scout leader to eliminate the new set of scouts in the hex.
While a unit is scouting, it cannot be deployed on the battlefield during mass combat until it has been recalled. The larger the scouting unit is, the more area it can cover (see Table: Unit Size and Scout Range). The time a scouting unit takes to be fully deployed depends on the unit's speed and the terrain, as determined in Table: Travel Time (1 hex) in the House Rules: Exploration & Movement section. When a scouting unit is recalled, the time it takes to regroup back at the army is increased by half, as time is needed to spread the word of the recall. If the area being scouted has more than one terrain type, then use the terrain with the slowest speed to calculate how much time it takes to deploy and recall the unit. If a scouting unit is recalled and reformed in the middle of a mass combat encounter, they appear in their army's Command Zone.
A garrisoned army can also deploy one of its units to scout the area around the settlement or base. Even though the unit is deployed for scouting duties, it is still considered garrisoned at the base and its Consumption is still paid monthly.
Table: Unit Size and Scout Range
| Designation | Number of Soldiers | Hexes Scouted | |
|---|---|---|---|
| Solo | 1 | 11 | |
| Squad | 10 | 21 | |
| Platoon | 25 | 1 hex radius | |
| Reinforced Platoon | 50 | 1 hex radius | |
| Company | 100 | 2 hex radius | |
| Reinforced Company | 200 | 2 hex radius | |
| Battalion | 500 | 3 hex radius | |
| Reinforced Battalion | 1,000 | 3 hex radius | |
| Regiment | 2,000 | 4 hex radius | |
| Reinforced Regiment | 4,000 | 4 hex radius | |
| Brigade | 8,000 | 5 hex radius | |
| Reinforced Brigade | 16,000 | 5 hex radius | |
| Division | 32,000 | 6 hex radius | |
| Corps | 64,000 | 6 hex radius | |
| — | (x2) | (+1 hex radius) | |
| 1 The army commander selects which hexes adjacent to her army to scout. She may change these hexes every two hours. | |||
Camouflage: An army’s ability to evade notice by other armies is reflected in its Camouflage score. The Camouflage score is equal to 10 plus 1/4 of the lowest Bluff, Disguise, or Stealth modifier (select the highest of the three) of the creatures comprising the unit, adding the leader’s LB (scout). Reduce the unit's Camouflage score by its size modifier. If a unit has Mounts, it uses the worse modifier of the riders or mounts. Since the size of an individual creature is already reflected in its Stealth score, it is not separately applied as a modifier to a unit’s Camouflage score. If no skill modifier is listed for a creature in its Bestiary entry, that modifier is equal to the creature’s Dexterity or Charisma modifier, modified for its armor and by -4 per size category larger than Medium, +4 per size category smaller than Medium. The terrain the army is hiding in may also provide a bonus to their Camouflage (see Terrain Battlefield Conditions).
When two armies enter adjacent hexes, each makes a Scouting check with a -5 penalty. If both succeed, both are aware of the other. If neither succeeds, neither is aware of the other, and the two armies may continue moving and could blunder into one another. If one army succeeds and the other fails, it can set an ambush for the other, lying in wait until the enemy army moves into its hex.
Ambushes: When one army is aware of another but has not been noticed itself, it is in position for an ambush. An army waiting in ambush gains a +5 bonus to its Camouflage score against an army that has already failed once to notice it. If the enemy army enters its hex, it can trigger the ambush. The ambushing army commander can choose where to deploy her battle zones to take advantage of terrain features, and can deploy its units in any of their own zone plus the enemy's Front zone.
At the start of the battle, both army commanders make an opposed Leadership check. If the ambushing commander's check is higher, then the ambushing units can be deployed in any of their zones or the enemy's Front zone, and all of the enemy army's units are considered to be in their Front zone. If not, then the enemy commander was able to react quickly to the ambush, and deploy units as normal. Regardless of the result of the Leadership check, for the duration of the ambush, the attacker gains the benefit of the Advanced Tactics command boon (gaining an additional +2 bonus to OM if it already has that boon). During this ambush round, the enemy army is unable to act during any battle phase except for the Rout phase. If the enemy army survives and does not rout, the battle proceeds to the Tactics phase and initiative is rolled normally.
If the enemy army fails to enter its hex, the ambushing army can hold its position and wait for the enemy army to spring the trap, or it can move to an adjacent hex and reset the ambush. Having to shift its position makes it easier to be discovered, and an ambushing army gains only a +2 bonus to Camouflage if it has to move.
If more than two armies (one on each side) are present, then usually all armies on one side of the battle must remain undetected in order for the ambush to be fully effective. At the GM’s option, however, it is possible for one or more armies to remain hidden while some of their allied armies engage in battle in the open. At the beginning of every Rout phase that occurs, however, all enemy armies present can make a Scouting check to notice these armies hiding in preparation to ambush. Hidden armies gain a +2 bonus to their Camouflage score as long as they remain stationary; they get no bonus to Camouflage if they had to move from their original position to reset their ambush. If any unit is detected, enemy armies sound an alarm and their opportunity for ambush is lost. Armies that are undetected cannot be attacked by the enemy. When they launch their ambush, it occurs after all other attacks have been resolved, immediately before the Rout phase.
Buildings: Certain terrain and settlement improvements automatically provide scouting over a range of hexes. The building and scouted area must be in hexes claimed by your nation. For example, a Watchtower on the border of your nation only scouts hexes in your nation, and not those beyond your border. However, an army garrisoned at that Watchtower can be ordered to scout hexes beyond your nation's borders, though that may cause a diplomatic incident if you are sending your troops into another nation's territory. Improvements have a base Scouting modifier of +0. If an army is garrisoned at the improvement, its uses the highest Scouting modifier among that army's unit leaders.
Table: Building Scouting Range
| Building | Scout Hex Radius |
|---|---|
| Watchtower | 1 |
| Barracks | 1 |
| Castle | 2 |
| Garrison | 2 |
| Fort | 3 |