Sweet potatoes are widely grown and enjoyed in Japan. They're baked, fried, served in stews and used to make desserts. Throughout history, they have offered a solution to food shortages. And nowadays, they can even help to keep a building cool in summer. Our guest, researcher Hashimoto Ayuki, introduces us to new ways of enjoying this versatile vegetable. And in Plus One, we see some innovative takes on mobile baked potato sales.

In the mountains of Okayama Prefecture, Kamimomi is a community whose features include beautiful terraced rice fields. But with fewer than 90 residents, it is at risk of disappearing. Here, Kyle Holzhueter from the USA engages in a form of natural construction that employs Japanese plastering techniques. One aim in all he does is a sustainable lifestyle, aligned with the power of nature. Peter Barakan learns about Holzhueter's way of life and the rich potential of Japan's rural communities.