In 1985, Kihachiro Aratake, a diver from Japan, was diving in the waters off the Southern shore of Yonaguni island and discovered something unusual. Upon inspection, it appeared to be a man-made, terraced structure. Believing he had discovered a sunken city, Aratake announced his discovery, but there was not much interest. 

Just south of Japan, you have a mysterious area called the Dragon’s Triangle, which is very similar to the Bermuda Triangle, because you have planes that have disappeared from the air, ships that have disappeared from the ocean.
In fact, Japan had declared this a disaster area.

In ancient Japan, and even into the relatively modern era, there are stories about the Dragon Sea, in which objects rise out of the water and sail through the air. These were winged monsters breathing fire… In more modern times, these took on the appearance of actual machines.
The Jomon Period of Japan

The earliest categorized period of Japanese history extending from roughly 8,500 BCE to 300 BCE.[1] The period is named for pottery bearing cord marks[2] from this period. The Jômon period in the Japanese islands may have seen the earliest invention (discovery) of pottery (ceramics) technology in the world.

The majority of Jômon pottery was, of course, quite simple and utilitarian in style and design. However, for a brief period towards the end of the Jômon period, some communities created exceptional vessels with flamboyant flame-like shapes; examples of these found in archaeological excavations show traces of food, and evidence of having been used over fires, thus indicating that these dramatic objects were, in fact, used for practical food preparation purposes.[3] Wide-eyed doll-like figures known as dôgu are also oft-cited examples of Jômon pottery; typically found broken in particular ways, archaeologists have surmised that these doll-like figures may have played a ritual purpose, being deliberately broken as part of the ritual of activating the object, in order to provide healing, or perhaps some other effect.