Brian Mockenhaupt has captured one platoon's effort to teach their replacements the lay of the land in the dangerous Arghandab Valley region in Afghanistan:

Lachance and his platoon mates called the area “The Devil’s Playground.” I’d seen the ledger of their time there, tallied in photographs. “He was killed. He was shot in the face. He broke his back,” Staff Sgt. Edward Rosa told me one night, pointing at pictures on a laptop screen in a small plywood-walled room at the outpost, part of a motel-like warren of sleeping quarters that 2 Charlie had built to augment the school’s half-dozen classrooms. “He’s gone. He’s gone. He’s gone,” Rosa said. His voice trailed off. 2 Charlie first came to Afghanistan in September 2009 with 42 soldiers; nearly half had been killed or wounded, mostly in the Arghandab.

But with the losses came experience.

After months of patrolling the valley, the platoon had learned bloody lessons about where to walk, which areas to avoid, and how to spot an ambush or a hidden bomb. Even an infantry unit would have trouble adapting in the middle of fighting season, but the incoming 101st artillery unit, trained to fire cannons that can lob 100-pound shells up to 20 miles, had the added burden of learning a new job. They had trained for several months on infantry tactics before deploying. Now the best 2 Charlie could do was walk through the area with them, and pass on scraps of accumulated knowledge.

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