Today’s yokai is a great example for the debate about what exactly is a yokai. I’ve mentioned on my blog and at talks that one of the four main categories of yokai is “phenomena.” While the vast number of yokai are creatures of some sort, there are supernatural things that are not actual creatures which still fall under the yokai umbrella. These are also called kaii, which means strange phenomena. Shinkirō is one of these.
Looking at the picture, you might guess that shinkirō is a magical clam. That’s close, but the term actually refers to the clam’s breath and not the clam itself. Although an argument could be made that the clam—with its enormous size and magical powers—is also a yokai, this specific term refers to a mirage that is blown out from the clam along with its breath.
Just like in other countries’ folklore, mirages at sea promised fantastic things to the sailors who saw them. In the case of Japanese folklore, they granted an image of a great castle at the bottom of the sea, where the dragon gods live. Wani, which was added to yokai.com last month thanks to my Patreon backers, would be an example.
An interesting little tidbit is that in Chinese, these clams are known as shen, and are actually shapeshifting dragons which take the form of clams. So they are even more connected to the dragon gods than they appear from just their breath!