This lagoon was formed when sandbars closed in the coastline. The lagoon is 16 km around, 6.7 km in area and 3 m deep. It has 5 islands and is fed by 6 rivers. Though referred to as a pond in Japanese, it is Japan’s largest pond.
Koyama Sand Dunes
Found just west of the mouth of the Sendaigawa River, these are the lowest dunes in height in Tottori at about 15 m. Once upon a time, families dug wells in their fields and the women had the grueling task of fetching water and carrying it over the dunes for the “kitchens of Tottori City.” Near Karo, there are hills of 30 m in elevation, but they stand on bedrock.
Legend of the Koyama Tycoon
Once upon a time, a rich man named Akasaka no Choja lived in Takakusanokoori. It was customary that the entire village would plant his rice paddies, which took a full day. One year, night began to fall and they had not finished planting the paddies. Not to be discouraged, Choja called for a gold fan and said to the sun, “Return for one hour.” Oddly, the sun, which had begun to set, started rising again and the village was able to complete the paddies in one day. However, the next day, the rice paddies had turned into a pond as far as the eye could see. Amongst the villagers spread a rumor that “the rice paddies were turned into a pond as punishment for beckoning the sun.” That pond is Koyamaike Lake.