The "Ji" (兕) mythical beast from China transformed into a distinctively Japanese form, believed to be a guardian lion-dog. It is depicted with a single horn on its head and is a protective creature. In pairs of statues commonly found in Japan, alongside the lion, it is represented on the left side with a closed mouth in a "un" (吽) shape when viewed from the front.
This model is considered to be a National Treasure from the Kamakura period, thought to have been created by Unkei's actual son, Tankei, or his workshop. It tilts its face upwards with a cute, tightly closed mouth, and its fangs peek out from both ends, exuding a charming, puppy-like quality.