Lake Biwa (琵琶湖) is Japan's largest lake and one of the world's oldest, formed by tectonic movement roughly four million years ago. From Nagahama the lake stretches west to the Hira Mountains, whose forested ridgeline forms the horizon. The view from the castle park — particularly in the late afternoon when the light turns the water pale gold — is the simplest pleasure the city offers, and costs nothing.
The lakeshore promenade running north and south from the castle is a good evening walk. Local people cycle and stroll here; in summer a few families swim from the small beaches. Sunrise over the lake from this side is particularly worth the early start: the Hira Mountains on the far shore catch the first light while the nearer water is still dark, and on still mornings the reflection is close to perfect.