Tatsuno Firefly Festival

Overview

Tucked into the mountains of the Ina Valley in southern Nagano Prefecture, the small town of Tatsuno has earned an outsized reputation as Japan's finest habitat for Genji fireflies (Luciola cruciata). The star venue is Matsuo Gorge — a narrow, forested valley carved by one of the Tenryu River's tributaries — where the cool, clean water nourishes vast colonies of Kawanina freshwater snails, the firefly's sole food source in its larval stage. The gorge was designated a Natural Monument of Nagano Prefecture in 1925, a recognition of how exceptional its firefly population already was a century ago. The Shinshu Tatsuno Hotaru Matsuri (Tatsuno Firefly Festival) has been held every summer since 1948, when the community revived it as part of postwar reconstruction. Over the decades it grew into one of Japan's most beloved summer events, drawing visitors from across the country who come specifically to witness thousands of fireflies rising simultaneously from the reeds and grasses along the river banks. When conditions are right — a still, warm, overcast evening — the darkness fills with slow, pulsing green-gold light that drifts between the tree canopy and the water surface in a display unlike any fireworks show. Food stalls line the approach from Tatsuno Station, and taiko drumming adds to the festive atmosphere before the crowds make their way into the park around nightfall. The festival park is laid out along a riverside walking trail that allows visitors to move through different intensity zones of firefly activity. Fireflies typically begin flying around 8 p.m., and slightly rainy or cloudy nights tend to bring the most spectacular displays, as the insects are more active in low-light conditions. The combination of an ancient gorge, traditional festival culture, and a genuinely wild natural phenomenon makes Tatsuno's firefly season an experience that is both ecologically remarkable and deeply rooted in local identity. Exact dates vary year to year — check the official website before planning your visit.

Access

📍 Address: Hirade, Tatsuno-machi, Kamiina, Nagano

From JR Chuo Line Tatsuno Station, the venue is about 5 minutes by car. Shuttle buses from the station operate during the festival period. By expressway, exit at Iho IC on the Chuo Expressway and drive approximately 7 km. Expect heavy congestion on festival evenings.

Map

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