On this edition of Journeys in Japan, the keyword is "water." Our reporter, Gow, travels to Yamaguchi Prefecture, in the far west of Japan's main island, where the power of water has created spectacular scenery, both above and below the ground. Her first stop is on the Akiyoshidai Plateau, where the karst rock has been eroded into unusual shapes. About 300 million years ago, this was part of a coral reef. She also explores some of the huge limestone caverns beneath the ground. One, called Akiyoshido, is full of impressive stalactites and other natural formations. It is designated as one of Japan's special natural treasures. Another, Kagekiyodo, is younger. Here, visitors can experience the thrill of exploring underground in total darkness. Gow's next destination is Nagato City, which lies right on the coast of the Sea of Japan. She visits the rice terraces of Higashi-Ushirobata and meets some of the people who live in this place, where land and water combine to form a landscape of great natural beauty.