Movement amongst the trees of a forest shows that the enemy is advancing. The appearance of a number of screens in the midst of thick grass mean that the enemy wants to make a us suspicious.

The rising of birds in their flight is the sign of an ambuscade. Startled beasts indicate that a sudden attack is coming.

When there is dust rising in a high column, it is the sign of chariots advancing; when the dust is low, but spread over a wide area, it betokens the approach of infantry. When it branches out in different directions, it shows that parties have been sent to collect firewood. A few clouds of dust moving to and fro signify that the army is encamping.

–Sun Tzu, The Art of War, Chapter IX: “The Army on the March,” [21-23].

Some of the more frustrating wargaming scenarios include hidden units on the tabletop. You know something is out there, but they remain off-table until triggered by a specific set of circumstances. Some scenarios use “chits” to indicate the possible location of forces, and you might have to make “scouting” rolls to see if they’re real or not.

If you don’t trust the person running the scenario, its best that you don’t play, even if you might get to play some of these “invisible” troops. Don’t play a game like this without an impartial referee.

Yet if you do trust the referee, here are a few guidelines to help you spot hidden troops without relying on birds and dust:

  1. Rugged Hills

If there’s a lot of rugged hills on the tabletop, chances are something is going to pop out of it. Don’t be surprised if something does.

  1. Woods.

If there’s a lot of woods on the tabletop, they’re hiding something.

  1. Ruins.

If there’s ruins on the tabletop, nasty things might emerge to attack you.

  1. Swamps.

There might be irregular troops hiding in the swamps, waiting to attack.

  1. Holes in the ground.

Abandoned mines. Tunnels for the Viet Cong. Any matter of dugouts can hide the enemy.

Perhaps now you see why scenarios like this are frustrating. You can’t trust anything. It’s hard to advance when you’re constantly on your guard. And if the referee is a jerk, he can really screw you over.

If you’re still inclined to play such a scenario, your best weapon is to ask the referee a lot of questions.

“Are there troops in those woods over there?” “What do I see?”

Base your decisions on how the referee and the opposing players react. Pay attention to their body language.

And if you get stonewalled. Don’t move forward. Don’t even bother. Drag the game out until it ends or your opponent gets impatient and shows himself.

Next on The Art of Wargaming:

How to Read Your Opponents Tactics.