By now we’re all familiar with the battle tactics in Game of Thrones: Confront your enemy head on—usually in some nicely arrayed lines—and hack at them until no one’s left alive or someone has won. It’s a tried-and-true method, with little in the way of actual operational depth. And as Sunday night’s Battle of Winterfell showed, it's particularly ineffective against an endless army of the undead. Spoilers ahead, obviously.

As the 82-minute episode opens, the allied forces of the living are ready to make their final stand against the undead forces of the Night King, a paramilitary commando who leads a death cult with a penchant for destroying everything you love. In military terms, the Night King is the center of gravity for the forces of the living: If they kill him, they have a shot at surviving the horde of the undead.

For his part, the Night King has an eye on Bran Stark, the S-2 intelligence officer for House Stark, what with his abilities to look backward and forward through time. Understanding his value as a target—he’s a good intelligence officer—Bran volunteers himself as bait to trap the Night King. The council of war agrees that this is the best option; it’s the only way to lure the Night King out from behind his forces. Plus, it falls into the hallowed military tradition of throwing the intelligence officer under the proverbial bus.

So far, so good. It’s at least a plan. From there, though, the allied forces are a mess.

This move, sometimes known as a “Custer,” predictably ends in ruin for the Dothraki cavalry.

Their first step should have been to establish an engagement area—a space in which they establish obstacles to disrupt and canalize the enemy so that they can be destroyed with direct and indirect fire. Using engagement area development, they could have used the time they had to incorporate a network of complex obstacles in front of Winterfell to slow and disrupt the waves of the undead. Instead, they left the field wide open. And what little strategy they did employ breaks down before the battle even begins.

Take the Dothraki cavalry. Putting that squadron forward of the main line of infantry was doctrinally correct, but the allied commanders did not put it to proper use: screening the allied lines and gaining active intelligence on the enemy. Instead, the Dothraki are ordered forward into an attack before the enemy situation is even known. This move, sometimes known as a “Custer,” predictably ends in ruin for the Dothraki cavalry, who get chewed up and spat out in an unsupported frontal attack. This destruction of the cav squadron leaves the allied forces without their reconnaissance assets.

Next we come to the issue of indirect fires. Any able field artillery officer could tell you that heavy-caliber indirect-fire weapons need to be positioned such that they’re both protected and mutually supportive of surrounding units. But the allies placed their batteries of trebuchets all along the lines, between the cav squadron and the infantry units. After a single initial barrage in support of the cav attack, they abandoned those mass-casualty producing weapons entirely. Had the batteries been positioned behind the anti-personnel ditch that protected the castle, they could have continued to execute both explosive and illumination fire missions. Yielding their indirect capabilities early left the infantry to fight alone, without the help of “stone rain.”

Speaking of which: The company deployed both heavy and light infantry, with their leadership in the front. This single line could merely slow the wave of enemy troops, while ensuring that allied leadership would be overwhelmed along with them. Forming their lines behind some protective obstacles would have ensured a longer defense.

Behind the infantry, the rear guard of the Unsullied ensured a defense in depth. And behind them, an anti-personnel ditch with chevaux de frise—anticavalry spikes—served as a protective obstacle before the outer wall of Winterfell. But placing this obstacle between the main body and the stronghold meant that a retreat would have to go through it, causing a choke point.