This posting is the third in a three-part series which explores how a Dungeon Master (DM) can apply accepted axioms of war to enhance the structure and mastering of combat encounters in a Dungeons & Dragons game. These axioms, and the historical examples used to illustrate them, are drawn from the writings of military historian Bevin Alexander, such as those found in Rules of War.
While not every monster in a D&D game will be familiar with all of the tactics described in this series, those who are intelligent or have intelligent leadership will certainly employ them if the need arises.
Thus far in this series, we’ve examined the tactics of striking at enemy weaknesses, defending, then attacking, and occupying the central position. This installment of the series will focus upon Operating on the Line of Least Expectation and Least Resistance.
Operating on the Line of Least Expectation and Least Resistance
From ancient times, a tried-and-true maxim of attack has involved striking at unexpected points at unexpected times, against undefended or lightly-defended targets. In The Art of War, the great Chinese military theorist Sun Tzu described the tactic as “throwing rocks at eggs.”
History provides numerous examples of the successful application of this maxim, including the Battle of Lake Trasimene, which took place during the Carthaginian General Hannibal’s invasion of Italy in 217 B.C. The Romans, under Consul Flaminius, expected to engage the Carthaginians on a flat plain in Tuscany, considering swamps adjacent to the nearby Arnus River to be terrain too difficult for Hannibal’s army to traverse; the route through the swamp was therefore unguarded. Seizing the opportunity, Hannibal marched his forces through the swamp and emerged behind the Romans, between Flaminius and Rome. Under cover of a thick fog, Hannibal deployed his forces with light infantry at the center, and his heavy infantry and cavalry hiding in ambush along the flanks. The light infantry was ordered to face away from the Romans and march to higher ground, above the fog, where they stopped with their backs still to the Romans.
Flaminius took Hannibal’s bait. Seeing the back of the Carthaginian light infantry, Flaminius believed that the visible troops were the rear guard of Hannibal’s army. Not wanting to squander an opportunity to fall upon what he believed to be Hannibal’s vulnerable rear guard, Flaminius ordered his troops out of defensive battle formation into faster, but much more vulnerable, columns, so that they could quickly descend upon the Carthaginians. About a quarter of the Roman army remained in battle formation, slowly advancing toward the objective.
The Roman columns marched right between Hannibal’s heaviest troops deployed at the flanks, where they were annihilated. The troops marching in battle formation arrived to find 15,000 dead Romans, and Hannibal had apparently moved on. They began to retreat toward Rome, but were captured by Hannibal’s forces en route.
Casualties and prisoners lost by the Romans at Trasimene exceeded 20,000.
Although combats in a Dungeons & Dragons game don’t involve nearly as many participants, the maxim of Operating on the Line of Least Expectation and Least Resistance can easily be applied to encounter design, especially for combat encounters in the current edition of the game, which favors much smaller parties of heroes than legacy editions of D&D.
Simply put, a small party of adventurers with only one or two defenders cannot effectively protect against monstrous attack from every direction, and the terrain a DM creates for a combat encounter can enable still more attacks from unexpected or indefensible angles.
Typically, players deploy their defenders toward the front of the party, where they expect the monsters to meet them head-on. Clever players will position their parties so that the back and/or flanks of the group are protected by walls, to limit monstrous angles of attack. But what happens if the combat environment doesn’t afford the heroes that luxury?
In such cases, the combination of terrain and superior numbers of monsters can make a difficult encounter into a deadly one. Consider these combat options:
- One of the walls the heroes are using to protect a flank is illusory, and monsters can simply attack through it.
- The terrain requires the heroes to march in single file, leaving at least one flank vulnerable for each hero, including lightly-armored strikers and controllers.
- Heroes may be tempted to use difficult terrain to help defend their positions, thinking that the movement limitations of the terrain will discourage foes from passing through it. But monsters who fly over or can pass unhindered through such terrain can easily attack those heroes.
- Even normally impassable terrain, such as acid, lava, or great heights, will not protect heroes from foes that can fly or teleport.
- Monsters with the ability to push, pull or slide heroic defenders can create a line of least resistance by forcing the heroes out of position, opening line of sight or line of effect to heroic controllers and ranged strikers.
While this is by no means an exhaustive list, it does illustrate how an inventive DM can use this combat maxim to create more exciting combat encounters and raise players’ tactical awareness.