Zao Okama Crater Lake

Zao Okama, also known as the 'five-color pond,' is a volcanic crater lake straddling the Yamagata-Miyagi border on Mount Zao, formed within the caldera of an active volcano and known for water that shifts between shades of emerald, blue-green, and grey-blue depending on light and mineral conditions. The lake is reached via the Zao Echo Line and Zao Highline toll roads, which climb through alpine scrub to the Katta Pass parking area, from which a short walking path leads to the main viewpoint directly above the crater rim. The near-circular lake, roughly 360 meters across, has no visible inlet or outlet and sits within stark volcanic terrain largely free of trees, giving unobstructed views down into the crater bowl. Most visitors spend 30 to 45 minutes at the viewpoint area, including the short walk from parking, weather permitting, since the summit is frequently subject to cloud and wind. The toll roads and lake access close each winter due to heavy snow, typically reopening in early May and closing again in early November. Midday visits in clear weather show the lake's color shifts most vividly, while early morning or late afternoon can bring low cloud that obscures the view entirely.