Japan is a world leader in utilizing underground space, and that's exemplified by its network of underground shopping streets. There are around 80 of these subterranean shopping centers across the country, selling the goods and services that Japanese people need in their daily lives. This time on Japanology Plus, our theme is underground shopping streets. Our guest is Yu Hiroi, an expert on urban disaster mitigation. And in Plus One, we visit Japan's oldest surviving underground shopping street.