Lake Yunoko

Lake Yunoko is a small, serene lake tucked at the very top of the Okunikko highlands, about 1,478 metres above sea level. It was formed when a lava flow from nearby Mount Mitsudake dammed a valley, trapping the water into a shallow crater-like basin. Fed by mountain streams and the hot springs of neighbouring Yumoto, its calm surface acts like a mirror, doubling the surrounding forest and peaks on still mornings and evenings. At its southern end the lake drains over a cliff to become Yudaki Falls, linking it into Nikko's famous chain of lakes and waterfalls.

The lake's great appeal is its tranquillity. It is far smaller and quieter than Lake Chuzenji downstream, and a flat walking path about three kilometres long loops the entire shore in roughly an hour. The eastern side runs near the road and the hot-spring village, but the western shore is roadless and wonderfully peaceful, threading through forest where deer are often seen at dawn and dusk. Wooden walkways cross marshy inlets, and benches invite you to sit and watch the reflections.

Seasons transform it. In summer the highland air is cool and fresh, and the lake is stocked for fishing - anglers cast for trout and char from the shore and small boats. Autumn, in October, is the showstopper: the encircling larch and maple forest turns gold and crimson and is thrown back perfectly in the water, one of the loveliest quiet foliage spots in the region. Winter buries the whole basin in deep snow, and the lake sometimes partly freezes.

Just beside the lake lies Yumoto Onsen, a rustic hot-spring resort whose milky, sulphurous waters have soothed travellers for centuries. The source springs bubble up in a small marshy field at the lake's edge, where you can see and smell the volcanic activity firsthand, and several inns and a public bathhouse let you soak after a walk. This combination of an easy lakeside loop and a genuine mountain onsen makes Yunoko a rewarding, low-effort destination.

Lake Yunoko sits at the head of the classic Okunikko walking route within Nikko National Park. From here the trail descends past Yudaki Falls, across the Senjogahara marshland and on to Ryuzu Falls and Lake Chuzenji - a mostly downhill day of some of Japan's finest highland scenery. Doing the walk from top to bottom means starting at Yunoko.

To reach it, take a Tobu bus from Tobu-Nikko Station bound for Yumoto Onsen and ride to the terminus, about 80 minutes up past Lake Chuzenji and the marsh. The lakeshore is a five-minute walk from the bus stop, and drivers will find parking. Because of the altitude the reliable season runs from late spring to autumn; come in October for the reflections or in summer for cool air and fishing.