Toyotacho in Shimonoseki City is known as one of Japan's famous firefly sites. Every June, when the fireflies are at their peak, you can enjoy a boat ride on the Koya River while watching the spectacular display of fireflies dancing on both banks. The approximately 800-meter boat trip is very magical and romantic. Fee: Boarding fee: Adults 2,000 yen (high school students and above), children 1,000 yen (from 5 years old to junior high school students) Location: Koya River, Toyotacho, Shimonoseki City Spectators: 3,300 people.