Gunning for Nepal

A distant clattering bounces off the snowy hills as 20 Maoist guerrillas approach a mountain pass deep in Nepal's rebel territory. The sound is too faint to fix as gunfire, so the guerrillas press on up the goat track. Then come the explosions.

The rebels halt and, panting in the thin air, squint up at the forest ridge that now marks the edge of the newest battlefield in their war. "Mortars," says a Maoist political officer. "Eighty-one millimeters," replies a teenage girl who has led the four-hour ascent from the valley floor. "And a chopper." Minutes later, a...