In Japanese mythology, Ryūjin is the dragon deity who rules the sea and lives in a jeweled underwater palace.
Ryūjin, also written Ryōjin, is a major sea kami in Japanese mythology and is often identified with Watatsumi. He is traditionally depicted as a dragon or as a powerful humanlike deity associated with the ocean. His palace, Ryūgū-jō, lies beneath the sea and is described in richly decorated, jewel-like terms.
Ryūjin possesses the tide jewels, magical objects that can raise or lower the sea. In the legend of Hoori, the hero travels to Ryūjin’s palace after losing a sacred fishhook. Hoori marries Toyotama-hime, Ryūjin’s daughter, and receives help recovering the hook. Their story connects sea power with the ancestry of Japan’s imperial line.
Ryūjin is sometimes confused with a generic Japanese dragon, but he is specifically a deity with authority over marine forces. Japanese dragons commonly control rain, rivers, and water rather than behaving like the winged, fire-breathing dragons of much European fantasy.