Japan is a land rich in folklore, and one of its most intriguing aspects is the presence of shape-shifting creatures known as yokai. These fantastic creatures take on various forms, ranging from demonic figures familiar to Western concepts, to humanoid, animal, or even plant-like entities. Some yokai are simply inexplicable phenomena, while others belong to a unique category known as tsukumo-gami. These are essentially haunted objects, such as tools, utensils, and even clothing, which develop their own consciousness. While tales of yokai have been passed down through the ages in oral tradition, it was Sekien who introduced the world to these creatures through the creation of his four books. These illustrated compendiums were not only groundbreaking in their time but have continued to inspire and captivate audiences for centuries.

In order to understand the significance of Sekien’s work, it is important to consider the religious and cultural context in which it emerged. Unlike the monotheistic religions predominant in the West, Japan’s indigenous faith, Shinto, and the later import of Buddhism celebrate a multitude of deities. Divine beings, called kami, can take countless forms and can inhabit anything, whether living or inanimate. From the natural elements like the sun and forests to abstract concepts like language itself, the presence of kami is believed to permeate every aspect of life.

While yokai are not part of the Shinto tradition and are not worshiped or venerated like kami, they exist as a distinct facet of Japan’s polytheistic worldview. Unlike the ethereal gods who reside in the heavenly plane, yokai dwell among humans and interact with them, often terrifying them in the process. Throughout history, these grotesque beings have been referred to by various names, including oni (ogre/demon), mononoke (strange things), bakemono (transformed things), and ayakashi (spooky things), among others. However, the term “yokai” has emerged as a more commonly used catch-all term to describe this diverse array of creatures.