Shikanoshima

In 1784 a farmer named Jinbei was repairing a ditch on the island's southwest shore when he turned up a gold seal about 2.3 cm square, with a coiled snake for a handle and five characters on the face: 漢委奴国王. It is generally thought to be the seal the Book of the Later Han says the Emperor Guangwu sent to the king of Na in 57 AD. The original is a National Treasure in the Fukuoka City Museum; Kin-in Park marks the find site with a monument and a view across Hakata Bay. Shikanoshima itself is small, 5.78 km² with about 11 km of coast, and a sandbar ties it to the Uminonakamichi peninsula, with a bridge since 1930. The loop road makes an easy half-day by bicycle; rentals are near the Shikaumi Shrine torii, a sea shrine where more than 10,000 deer antlers have been offered. Shiomi Park, near the top, looks out over the whole bay. Buses on the island are infrequent, so check the timetable before you pick a ferry back.