Overview: Since the outbreak of COVID-19, people all over the world have become accustomed to wearing masks. But in Japan, a custom of mask-wearing dates back hundreds of years. Today, innovations are addressing the communication problems that masks can cause. Our guest, science historian Sumida Tomohisa, offers his views on why Japanese feel so at ease wearing masks. And in Plus One, Lemi Duncan looks at ways to make masks more fashionable.