Sanryoo Shrine Offering Hall

Sarureo Shrine Heiden: A Meiji-Era Offering Hall Guarding an Ancient Royal Tomb

Nestled atop a gentle hillock on the southern plains of Marugame City in Kagawa Prefecture, the Sarureo Shrine Heiden (讃留霊王神社幣殿) stands as a remarkable bridge between Japan's ancient mythology and its refined Meiji-era craftsmanship. This elegant offering hall, registered as a Tangible Cultural Property of Japan, serves as the architectural guardian of a kofun (ancient burial mound) believed to be the final resting place of the legendary Sarureo — the heroic prince who slayed a monstrous sea creature and became the spiritual king of Sanuki Province.

The Legend of Sarureo: Sanuki's Mythical Sea Monster Slayer

The story behind this shrine is one of the most captivating legends in all of Shikoku. According to ancient chronicles recorded in the Kojiki and Nihon Shoki, during the reign of Emperor Keiko (the 12th emperor of Japan), a terrifying giant fish appeared in the seas around Shikoku, devouring ships and terrorizing fishermen. The emperor commanded his son, Yamato Takeru, to subdue the beast, but Yamato Takeru instead recommended his own son, Prince Takekaikoo (武殻王), for the mission.

The young prince assembled a fleet of over eighty warriors and set sail to confront the monster. In a dramatic turn, the creature swallowed the prince and his entire fleet whole. Undaunted, Takekaikoo lit fires inside the beast's belly and slashed his way out from within. Though the monster perished, the warriors were left near death from its poisonous vapors. At that moment, a divine youth appeared riding on clouds from the direction of Shiramine, carrying a sacred vessel of water. When the warriors drank from it, they were miraculously revived. This water became known as the "Yasoba no Shimizu" (Waters of the Eighty), a place that can still be visited in nearby Sakaide City.

For his heroic deed, the prince was granted dominion over Sanuki Province. He settled there, taught the people sericulture and silk weaving, and came to be revered as "Sarureo" — meaning "the spirit king who remained in Sanuki." Upon his death at a legendary age, he was buried on a scenic hilltop overlooking his domain, and a shrine was erected in his honor. His descendants became the powerful Aya clan, who prospered in this region for generations.

Architectural Significance: Why the Heiden Is a Registered Cultural Property

The heiden (幣殿), or offering hall, of Sarureo Shrine was built during the Meiji period, between 1898 and 1912. Despite its relatively recent construction, it was registered as a national Tangible Cultural Property on March 27, 2018, owing to its exceptional traditional architectural techniques and its unique design features that reflect the shrine's deep connection to the ancient tomb behind it.

The structure is a single-bay wooden building in the irimoya-zukuri style (hipped-and-gabled roof) with a hirairi (front-facing) entrance. Originally roofed with hinoki cypress bark (hiwadabuki), it is currently covered with temporary copper sheeting to preserve the original structure. The building area measures approximately 6.0 square meters — compact yet exquisitely detailed.

Several architectural elements make this heiden particularly noteworthy. Round pillars (enchū) support an elaborate double-stepped bracket system (nidesaki), while the eaves feature an elegant fan-pattern arrangement of rafters (ōgi-daruki) in a double-rafter (futanoki) configuration. A veranda (en) encircles all four sides of the building, creating a sense of openness and accessibility.

The most distinctive feature is the placement of latticed Chinese-style doors (san-karado) on both the front and rear of the building. While most shrine buildings face only forward, this heiden opens toward the rear as well, allowing a direct spiritual connection with the Sarureo Kofun — the ancient burial mound that serves as the shrine's sacred object of worship (goshintai). This dual-facing design is highly unusual among Japanese shrine architecture and speaks to the profound relationship between the building and the tomb it guards.

The Sacred Compound: Heiden, Torii, and Tamagaki

The heiden does not stand alone — it is part of a carefully composed sacred landscape. In 2018, three structures within the Sarureo Shrine compound were simultaneously registered as Tangible Cultural Properties: the heiden (offering hall), the torii gate, and the tamagaki (sacred fence).

The stone torii gate, located partway up the stairs leading from the eastern entrance to the worship area, bears an inscription dating it to the 13th year of the Bunsei era (1830). This Myōjin-style torii features slightly inward-leaning pillars and a gracefully curved kasagi (top beam), preserving the historic atmosphere of the precinct.

Together, these three registered structures form a cohesive ensemble that tells the story of centuries of devotion to the legendary Sarureo, from the Edo-period stone torii to the refined Meiji-era offering hall.

The Kofun: An Ancient Burial Mound as a Living Shrine

Behind the heiden lies the Sarureo Kofun, a keyhole-shaped burial mound (zenpo-koen-fun) dating to the early Kofun period (approximately 4th century CE). The mound is oriented directly northward, aligned with the iconic cone of Mount Iino (Sanuki Fuji), which rises majestically on the horizon beyond the shrine's approach path.

This alignment is believed to be intentional, with Mount Iino serving as a kind of natural grave marker pointing toward the North Star — symbolizing the deceased's role as a heavenly ruler of the land. Some researchers have also noted that the shrine's orientation corresponds to the summer solstice sunrise, adding another layer of astronomical and spiritual significance to this ancient sacred site.

Unlike many ancient tombs that have been excavated and studied, the Sarureo Kofun remains unexcavated, preserving its mystery and sanctity. It continues to function as the goshintai (sacred body) of the shrine — a living archaeological site that still serves its original spiritual purpose after more than 1,600 years.

Highlights and Visitor Experience

Visiting Sarureo Shrine offers a unique experience that combines ancient mythology, traditional architecture, and the serene beauty of the Sanuki countryside. Here are the key highlights for visitors:

• The Meiji-era heiden with its rare dual-facing doors, showcasing refined traditional carpentry including fan-pattern rafters and double-stepped bracket systems.
• The view northward from the shrine approach toward Mount Iino (Sanuki Fuji), one of Shikoku's most recognizable landmarks, creating a dramatic visual connection between the ancient tomb and the sacred mountain.
• The atmospheric climb up stone steps past the 1830 Bunsei-era torii gate, ascending through the quiet hillside precinct.
• The Sarureo Kofun itself — a keyhole-shaped burial mound that has served continuously as a sacred site for over sixteen centuries.
• The peaceful rural setting among the rice paddies and gentle hills of the Marugame plain, far from the tourist crowds, offering an authentic glimpse of traditional Shikoku life.

Nearby Attractions

The area surrounding Sarureo Shrine offers numerous opportunities to extend your cultural exploration:

Mount Iino (Sanuki Fuji) — Located just north of the shrine, this beautifully symmetrical 422-meter peak is one of the "New 100 Famous Mountains of Japan." The gentle hike to the summit takes about one hour and rewards climbers with panoramic views of the Sanuki Plain and the Seto Inland Sea. During mid-April and late August, the rare "Double Diamond Sanuki Fuji" phenomenon can be observed when the sunrise aligns with the peak and its reflection in nearby ponds.

Marugame Castle — About 6 kilometers northwest, this castle boasts the tallest stone walls of any castle in Japan and a beautifully preserved wooden keep designated as an Important Cultural Property. The castle grounds are especially stunning during cherry blossom season.

Kaitezan Kofun — A nationally designated historic site located in the southeastern hills of the Marugame Plain. At 98.8 meters in length, this is the largest early Kofun-period burial mound in all of Shikoku, offering important context for understanding the ancient power structures of Sanuki Province.

Sanuki Udon — No visit to Kagawa Prefecture would be complete without sampling its world-famous udon noodles. Marugame City and the surrounding area are home to countless udon shops, each with their own unique style and traditions.