For decades, people thought that the most impressive natural sight you could see near the Japanese island of Yonaguni was the frenzy hammerhead sharks that circled the shores during the chilly winter months. That all changed in 1987 when local scuba diving instructor and director of Yonaguni-Cho Tourism Association Kihachiro Aratake discovered something underwater that was far more interesting than sharks. It was the mysterious Yonaguni monument. It is a gigantic underwater rock formation cut into a series of immense geometric terraces, with broad, flat horizontal surfaces, and sheer vertical stone risers. The formation is mostly composed of sandstone and mudstone, while various structures connect to the rock beneath them. The most prominent part of the Yonaguni Monument is a giant slab of rock that is nearly 500 feet long, 130 feet wide and 90 feet tall. The distance from the surface of the water to the top of the monument is around 16 feet.
The discovery sparked a debate as to whether they are naturally formed or man-made structures created by an ancient civilization. What makes many people — including some scientists — believe that the monument is more than just a giant piece of rock underwater is the variety of details that point to human influence. There are what looks like couple of pillars, a stone column, and a wall that is 33 feet wide, a road, and even a star-shaped platform. If the monument is indeed man-made or modified by humans, that would date it back to the last Ice Age, around 10,000 years BC, when the sea level was 40m lower than it is now and Yonaguni Jima was part of a land bridge connecting Japan, Taiwan, and China mainland. This would make the monument the oldest man-made artifact on The Earth, significantly pre-dating the pyramids of Egypt. Masaaki Kimura, a marine geologist has been studying the object for many years and is convinced that the site was carved thousands of years ago when it was still above water. Precise angles and triangle carvings are unlikely to have a natural origin. He believes that the structure could be the remains of the Lost Continent of Mu, the Japanese Atlantis. However, other scientists do not agree and insist that geology and strong currents are responsible for the unusual shape of the rock.
While it is not officially a sunken city, the Yonaguni Monument certainly draws tourists like one. The site is mostly popular among divers. To reach the island you can sail on a ferry which makes the journey between Ishigaki and Kubura Port on the western end of Yonaguni Island every twice a week. A one way journey takes approximately 4.5 hours.
Yonaguni is a tiny speck of an island (28 sq. km.) with a population of less than 2000 people, located 125 km from Taiwan and 127 km from Ishigaki. There are three villages on the island: Sonai, as the most populous village in the north, the fishing village of Kubura in the west and Higawa in the south. Higawa has only around 100 inhabitants. A free community bus runs about once every two hours along the western half of the island and serves the three villages. Besides the public bus, rental vehicles like cars and mopeds are also available on the island.
Although it lacks the resorts of the larger Yaeyama islands and its few visitors are mostly divers coming to witness the island’s mysterious sunken ruins and hammerhead sharks, the island has beautiful (yet uncrowded) beaches, cultural attractions, and various mysteries of history. Whether you believe the monument is a man-made structure or a natural-rock formation, it is still an incredible sight. And it is not the only amazing dive site in Yonaguni. Divers have surveyed numerous sites here. Many feature beautiful caverns and caves, pristine coral reefs, and other striking features, such as large fields of anemones and enormous gorgonian fans. And better still, even in November the water temperature is 84 F (29 C), thanks to a warm current that runs up the east coast of Taiwan. Yonaguni has the oceanic climate prevailing and the best time to visit the island is from January until December, when you will have a pleasant or warm temperature and limited until mediocre rainfall. The highest average temperature on Yonaguni is 29°C in July and the lowest is 20°C in January.
The island is known for its marine activities as well as for its native fauna; Yonaguni horse. Yonaguni is home to the Yonaguni horse, this pony-sized horse is a native Japanese breed, typically have brown hair and were originally used as riding horses. Today they are a protected breed and allowed to roam freely in the three pastures near the villages. Texas gates, a grid of slates above a depression on the road, act as a barrier and deter the horses from leaving the pastures.
Below are some other attractions on Yonaguni Island:
Westernmost Point and Irizaki Lighthouse
The western cape of Yonaguni and some stones in the water off the cape make up Japan’s westernmost point. As such, it is also the last place in the country to see the sunset. Irizaki Lighthouse and a monument celebrating the extreme point can be found at the cape. Taiwan can be seen just over 100 kilometers across the sea in the distance when visibility is good.
The Agarizaki Lighthouse stands at the opposite end of the island, at the eastern cape of Yonaguni. It is surrounded by spectacular, high sea cliffs that make up the coastline. Iriomote Island can be seen in the distance when visibility is good. The pony-sized, native Yonaguni horses are often seen roaming the pastures around the Agarizaki Lighthouse.
Gunkan and Tategami rocks
The coast southeast of Yonaguni’s western cape continues to offer a spectacular scenery with rugged terrain, high sea cliffs and numerous notable rock formations. Of interest are the Gunkan-iwa, a stout and imposing rock named after a warship, and Tategami-iwa, a tall candle-shaped rock. There are multiple lookout points along the road.
Tindabana is rock outcrop that towers about 85 meters above the village of Sonai. A lookout point in the outcrop offers panoramic views of the village, the nearby Nanta Beach, and the East China Sea. The viewpoint is reached via a 200 meter long walking trail along the cliff from the nearest parking lot.
Atlas Moth Museum
The Atlas Moth Museum is located in the middle of the eastern half of Yonaguni. The museum displays the Atlas Moth – or Ayamibabiru as it is known locally – which is the largest moth in the world. The museum introduces the habitat of the tropical moth, and visitors will be able to see them up close as well.