Finding enemy guns

Each enemy army keeps 1 to 3 field guns hidden behind its lines. You never see them fire. They wear down your trenches, and once they know where Old Marta is, they hunt her. Finding them is a patient game of bearings and ellipses.

What their guns do

Every 40 to 90 seconds an enemy gun fires a short barrage at your front line, and each hit damages a trench segment. Your own trenches report it by radio, so you know even under fog. See Trenches.

Once a battery has triangulated Old Marta, it starts hunting her as well. The first shells land wide, then they creep closer. See Exposure and moving the gun.

The Mustard Company leans on its guns most of all: their artillery, and counter-battery fire on you, is their signature threat. See The three armies.

Bearings and the ellipse

Flash-spotters and sound-rangers give you one bearing line for each enemy shot. Two or three lines cross in an error ellipse on the map table, and each extra bearing draws it tighter.

Then the hunt goes like this:

1. Collect bearings. Each time the gun fires, another line goes onto the map.
2. Fire into the ellipse. Two or three lines are enough for a usable one.
3. Confirm with recon. Send a balloon's circle or a plane's path over the ellipse to see what you hit. The gun itself never appears on your map until recon has seen it. See Recon: spotters, balloons and planes.

A gun pit you destroy stays on your map as ruins. See The intel map remembers.

Shells into the ellipse are not the only answer. Cutting the rail junctions and bridges behind the enemy line can trap an enemy gun on a dead-end siding. See The rail network. Some story operations are about one gun alone, such as "Silence the gun that shelled the bakery".

Counter-battery duels

They hunt you the same way you hunt them. Every shot you fire gives them a little more on Marta, and every shot they fire gives you another bearing on them. Their ranging shots creep toward your yard while your ellipse closes around their gun. In the yard you hear each incoming shell 3 to 5 seconds before it lands.

That is the duel: fire into the ellipse before they find their range, or limber up and move and start again from a new siding. Counter-battery duels arrive in spring, the season called "Two Rivers", when the Mustard Company enters the war and enemy sound-ranging starts to hunt you. See The campaign: four seasons.