Originally harnessed by Japanese craftsmen over four hundred years ago for its natural purifying properties, activated charcoal has recently undergone something of a renaissance. What was once a little-known secret has transformed into a popular resource with hundreds of users and just as many uses. Its most creative interpretation may just be the Chikuno Cube, an ingeniously designed miniature air refresher that uses the properties of charcoal to banish odors and humidity around the house. In this special Deep Dive series, we explore the Chikuno Cube, from its origins in the charcoal kilns of Kyoto to the science behind its unusual honeycomb structure.