or is the supernatural undersea palace of Ryūjin or Dragon God in Japanese tradition.
It is best known as the place in fairytale where Urashima Tarō was invited after saving a turtle, where he was entertained by the Dragon God's princess Oto-hime and his minions. When Urashima returned to land after what he thought was a few days away, centuries had passed.
Overview
Ryūgū or Ryūgū-jō is the fabulous mythical residence of the Ryūjin (Dragon God) or Sea God, or the princess Otohime. Chamberlain had freely substituted more ancient text material into his retelling of the Urashima fairytale. Chamberlain also interchangeably uses "Sea God's Palace", probably with the archaic god-name Watatsumi in mind.
Eventually, the Dragon Palace undersea became the standard in modern tellings of the Urashima tale. A canonical example by the Taisho Era, according to one researcher, was the edition by Mori Rintarō (novelist Mori Ōgai) and others, published 1920–1921, whose illustration shows Urashima and the turtle peeing underneath at the palace.
Palace architecture
"The walls of the Palace were of coral, the trees had emeralds for leaves and rubies for berries" (Chamberlain), roughly coincides with the inner chambers being fashioned with according to Meiji Era akahon ehon ("red book" editions).