At an elevation of about 1,650 meters, Ishi-no-yu in Shiga Kogen is known as the highest-altitude breeding ground for Genji fireflies in Japan. They are at their best from early July through mid-August. Here you can take in the dreamlike glow of these fireflies, designated a National Natural Monument, and a sky full of stars all at once.
Ishi-no-yu in Shiga Kogen is a celebrated spot, renowned as the highest-altitude breeding ground for Genji fireflies in Japan. Hot spring water wells up along the banks and flows into the mountain stream, nurturing the kawanina snails that the firefly larvae feed on, which is why Genji fireflies can be seen here even at a high elevation of around 1,650 meters. In 2008, these distinctive conditions were recognized with a designation as a National Natural Monument.
The fireflies are at their peak from early July through mid-August (with the height of the season running from mid-July to mid-August). Watching them drift through the darkness while the stars seem to pour down from above is a pleasure unique to the high country of Shiga Kogen.
