Tenguiwa is a rock, and it is a rock with a long reputation. It stands in the sea near Okinoshima, the sacred island that lies about sixty kilometres off the north coast of Kyushu in the Genkai Sea, midway between Japan and Korea, and it belongs to the World Heritage listing of the Sacred Island of Okinoshima and Associated Sites in the Munakata Region. The name means the Tengu's rock, after the long-nosed goblin of Japanese folklore, and it is one of a few small islets and reefs that rise around the main island, used by sailors as marks and treated with respect as part of the sacred place.
Okinoshima is one of the most restricted places in Japan. Since the fourth century, people crossing the sea between the mainland and Korea and China made offerings here to the goddesses of the Munakata shrine, asking for safe passage, and they left mirrors, gold rings, beads, weapons and fine objects, some of which came from as far as Persia. More than eighty thousand items have been found, all classed as national treasures, and the island has been called the Shosoin of the sea. Today no one may land except a single Shinto priest on a rotation, women are not permitted, and men who visit once a year, on the day of a memorial ceremony in late May, must strip and purify themselves in the sea before stepping ashore. Visitors are not allowed to take anything from the island, nor to speak of what they see.
For an ordinary rider, the experience is therefore from afar. The nearest ways to feel the place are on the mainland, at the shrine of Munakata Taisha, whose Hetsu-miya sits near the town of Munakata, and on Oshima, a small island reachable by ferry, where the Okitsu-miya worship hall faces the open sea and, on clear days, Okinoshima itself can be seen as a faint shape on the horizon. The coast road along the Genkai Sea through Munakata and Fukutsu is a pleasant run, with fishing ports, pine groves and sea views.
Fuel and food are in Munakata, and the ferry terminal has a small shop and a restaurant that serves fresh fish. Check ferry timetables in advance, since weather in the strait can cancel crossings. Summer is hot and humid, with typhoon risk in late summer and autumn, and the best months are April to June and October.