Inogashira Park Firefly Grove

Overview

Inogashira Park (Igashira Koen) stretches across Moka City in Tochigi Prefecture, fed by naturally springing groundwater that keeps its ponds crystalline even through summer. Within this green sanctuary, the Firefly Grove — a carefully tended stretch of stream and meadow — offers something increasingly rare in modern Japan: a genuine wild firefly display within easy reach of the city. The fireflies here are primarily Genji fireflies (Luciola cruciata), the larger of Japan's two celebrated species, whose slow, sweeping pulses of light set them apart from their smaller Heike cousins. The stream corridor has been maintained without concrete embankments so that the freshwater snails the larvae feed on can thrive naturally, and the surrounding vegetation is managed to preserve the dark, humid microclimate the adult beetles require to breed. When conditions align — warm, calm evenings in mid-June through early July — hundreds of lights begin to drift above the waterside grasses after sunset, turning the path into something closer to a dreamscape than a municipal park. Outside firefly season, Inogashira Park rewards a visit in every month. Cherry blossoms crowd the lakeshore in April; iris and rabbit-ear iris paint the wetland margins purple in late May and June; autumn foliage reflects in the still water come October and November. Rowboats and fishing round out a full-day itinerary. The fireflies, though, are the park's rarest offering — a reminder of what patient, community-led conservation can preserve.

Access

📍 Address: 99 Shimokagoya, Moka, Tochigi

About 10 minutes by car from Moka Station (Moka Railway) or 5 minutes from Moka IC on the Kita-Kanto Expressway. Parking fills quickly on weekend evenings during firefly season — arriving early is strongly advised.

Map

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