On the coast of Japan, a massive coin-shaped pattern resembling ancient Chinese coins has been discovered. This three-dimensional coin design is made from piled sand, and from a distance, it appears as a series of sand trenches. Only from the summit of Kintan Mountain can one clearly see this circular pattern, which closely resembles an ancient coin. At the center of the pattern is a square hole, with the characters "Yong Kuan Tong Bao" inscribed on its four sides. Measurements show that this coin pattern is not a perfect circle but rather an oval shape.
There are two theories regarding the formation of this giant coin pattern. One theory suggests that in 1633, local residents constructed it overnight from excavated sand to welcome the lord of the Ryūmaru domain. The other theory is linked to a myth: in 703 AD, the deity Hachiman descended from the cosmos on a glowing ship to the summit of Kintan Mountain, where people built a shrine in his honor, leaving behind this pattern. These legends have sparked further imagination about the design, with some speculating it could be a remnant of extraterrestrial civilization.
The existence of this coin pattern raises a series of questions: Who built it? For what purpose? How has it withstood the test of time without being eroded by seawater? People are trying to find answers from historical and natural perspectives, but the significance of its existence remains elusive.
