Top: Kawauchi, Fukushima Prefecture 2012 Bottom: Chernobyl, Ukraine 2006 1 Kanno, 65, says he’s thinking of digging a well so he can live and farm in the valley again one day.

Akihiko Kondoh, a hydrologist also at Chiba University, says the spring could be contaminated with radioactive cesium if heavy rains flood the area. Kanno extends a thick brown finger, carefully tracing the path of the water from its upslope source down to the house that he is permitted to visit but no longer live in. “So where did you say the drinking water spring is?” asks Tatsuaki Kobayashi, a restoration ecologist at Chiba University, as he studies a print showing the valley’s forest-and-field patchwork. The idle fields are illuminated by lights from his house, where several men bend intently over a low wooden table as they pore over satellite photographs and contour maps. In a narrow wooded valley just inside the Fukushima evacuation zone, a cold mountain dusk is falling over the terraced plots where Genkatsu Kanno grew rice and vegetables for most of his life.