Ryugu-jo: Inside the Underwater Castle of Japanese Myth
Deep beneath the swirling currents of the ocean, mythology tells of a palace built from red and white coral, guarded by sharks, and ruled by the Dragon God. This is Ryugu-jo (The Dragon Palace Castle), one of the most enduring and enchanting locations in Japanese folklore. While Western mythology looks to Atlantis, Japan looks to this underwater utopia where time stands still and the seasons exist simultaneously.
For cultural travelers and folklore enthusiasts, understanding Ryugu-jo is essential to appreciating Japanese storytelling. From ancient scrolls to modern anime, the Dragon Palace continues to captivate the imagination.
Origins and Mythology
The concept of Ryugu-jo is deeply rooted in Shinto beliefs and maritime traditions. It is the residence of Ryujin (also known as Watatsumi), the Dragon God of the Sea who controls the tides and the creatures of the deep. In the lore, the palace is described as a majestic multi-storied structure made of crystal and coral, adorned with sloping roofs that reflect the architectural style of mainland Japan, yet adapted for an aquatic realm.
One of the most fascinating aspects of Ryugu-jo is its relationship with time. Similar to the concept of the Feywild in European folklore, time flows differently within the palace walls. A few days spent feasting with the Dragon God can equate to hundreds of years passing in the human world above. This sorrowful temporal distortion is the linchpin of the most famous story associated with the castle.
The Legend of Urashima Taro
While Ryugu-jo appears in various myths, it is inextricably linked to the tale of Urashima Taro, often called the Japanese Rip Van Winkle.
The story begins with a young fisherman named Urashima Taro, who rescues a small turtle from a group of tormenting children. Days later, while fishing, a giant sea turtle approaches him and reveals that the small turtle was actually the daughter of Ryujin, the Princess Otohime. To reward his kindness, Taro is invited to Ryugu-jo.
Riding on the turtle’s back, he descends into the ocean depths. At the palace, he is welcomed as a hero. He spends what feels like three days enjoying the finest foods, mesmerizing dances, and the company of the beautiful princess. However, homesickness eventually strikes, and Taro asks to return to his aging parents.
Princess Otohime grants his wish but gives him a mysterious jeweled box (tamatebako) as a parting gift, with a strict warning: never open it.
Upon returning to his village, Taro finds everything changed. His house is gone, and he recognizes no one. He discovers that while he was gone for three days, 300 years had passed on land. Overcome with grief and confusion, he opens the box. A cloud of white smoke erupts, and Taro instantly transforms into an old man. The box had contained his old age, kept at bay by the magic of Ryugu-jo.
Ryugu-jo in Modern Culture
The imagery of the Dragon Palace is pervasive in modern Japanese media, proving that ancient myths evolve rather than vanish.
- Anime and Manga: In the massive hit One Piece, the Fish-Man Island arc features the Ryugu Palace, clearly inspired by the legend. Similarly, the Dragon Ball series draws heavy inspiration from the Journey to the West, which shares cross-cultural ties to dragon king mythology.
- Video Games: Fans of Animal Crossing will recognize the character Kapp’n, a turtle (kappa) who sings sea shanties and transports players, a nod to the turtle transport in the Urashima legend. The Pokemon universe also references these myths through various water-type lore.
- Architecture: The aesthetic of the underwater castle—vermilion gates and curved roofs—is often replicated in seaside resorts and public baths (sento) across Japan to evoke a sense of luxury and escape.
Traveler’s Tips: Finding Ryugu-jo in Real Life
While you cannot visit the actual underwater castle without a submarine and a suspension of disbelief, several locations in Japan offer a tangible connection to the legend.
1. Katase-Enoshima Station (Kanagawa Prefecture)
Perhaps the most accessible “Ryugu-jo” for tourists is located just an hour south of Tokyo. The Katase-Enoshima station building is designed explicitly to look like the Dragon Palace. With its vibrant red pillars and green roof tiles, it is a fantastic photo opportunity before exploring Enoshima Island, which is dedicated to the Goddess Benten and a five-headed dragon.
2. Ryugu Shrine (Kagoshima Prefecture)
Located on the Satsuma Peninsula at Cape Nagasakibana, this shrine is said to be the actual setting where Urashima Taro departed for the palace. It is a stunning coastal location with views of Mount Kaimon. Visitors write their wishes on oyster shells rather than wooden plaques.
3. Ibusuki (Kagoshima Prefecture)
The Ibusuki sightseeing train, known as the “Ibusuki no Tamatebako,” is a black and white train designed to represent Urashima Taro’s hair turning white. When the doors open, steam (mist) sprays out to simulate the smoke from the legendary box.
Sources & Further Reading
For those wishing to delve deeper into the primary sources of these legends, the following historical texts are essential:
- The Kojiki (Records of Ancient Matters, c. 712 AD): Contains early references to the sea deity Watatsumi and the Palace of the Sea God.
- The Nihon Shoki (Chronicles of Japan, c. 720 AD): Provides alternative versions of the myths found in the Kojiki, offering a more historical perspective on the lineage of sea gods.
- The Otogi-zoshi: A collection of Muromachi-period narratives that solidified the version of the Urashima Taro story that is most popular today.