Excavated Treasures of Mount Asakuma's Sutra Mounds: Where Shinto Priests Secretly Prayed to the Buddha

High on the misty slopes of Mount Asakuma, overlooking the sacred precincts of Ise Grand Shrine, lies one of Japan's most remarkable archaeological discoveries. The Excavated Items from the Sutra Mounds at Kyōgamine, Mount Asakuma, Ise Province (伊勢国朝熊山経ケ峯経塚出土品) is a collection of Heian-period artifacts designated as a National Treasure of Japan. These exquisite objects — bronze mirrors engraved with images of Amida Buddha descending from paradise, sutra tubes inscribed with the names of Shinto priests, and hand-copied Buddhist scriptures — tell an extraordinary story of spiritual devotion that transcended the boundaries between Japan's two great religions.

What Are the Sutra Mound Excavated Items?

A sutra mound, or kyōzuka (経塚), is a burial site where Buddhist devotees interred sacred scriptures inside containers, placing them deep underground along with ritual offerings. The practice arose during the late Heian period (794–1185) from the belief that the world had entered Mappō, the prophesied "Age of the Decline of the Dharma," in which the Buddha's true teachings would gradually disappear from the world. By burying sutras in durable containers, the faithful hoped to preserve the sacred texts for future generations or for the coming of Maitreya, the Buddha of the Future.

The artifacts designated as this National Treasure come from three of the 43 sutra mounds discovered at Kyōgamine (Sutra Peak), a ridge northwest of the main hall of Kongōshōji Temple atop Mount Asakuma. The collection comprises items from the First, Second, and Third Sutra Mounds, dating between 1159 and 1173 during the late Heian period. Together, they form one of the most important and best-preserved sutra mound assemblages in all of Japan.

A Discovery Born from Disaster

The story of this National Treasure begins with catastrophe. In September 1959, the devastating Isewan Typhoon — the most powerful typhoon in Japan's recorded history at that time — struck the Kii Peninsula, causing enormous destruction across the Ise-Shima region. Mount Asakuma, the highest peak in the area at 555 meters, suffered severe landslides and uprooted trees.

During the subsequent cleanup and fallen-tree removal operations in 1959 and 1960, workers unexpectedly unearthed bronze sutra tubes, mirrors, and other artifacts from the disturbed soil. Though a ceramic sutra tube had already been found during the Meiji era in 1894, the typhoon-related discoveries prompted the first systematic archaeological excavation, which ultimately revealed a total of 43 sutra mounds — an extraordinarily large cluster representing decades of continuous devotional activity.

The excavated items from the three most significant mounds were collectively designated as an Important Cultural Property in 1912 (for the earlier Meiji-era find), and then elevated to National Treasure status on July 1, 1963. The sutra mound site itself was designated as a National Historic Site in 1966 under the name "Asakumayama Sutra Mound Group."

The Designated Artifacts: A Closer Look

The National Treasure designation encompasses artifacts from three sutra mounds, each containing objects of outstanding historical and artistic significance.

The Line-Engraved Mirrors: Masterpieces of Devotional Art

The four line-engraved mirrors from the Third Sutra Mound are widely considered the artistic highlight of the entire collection. Created by skilled metalworkers using a burin to incise fine lines into polished bronze surfaces, these mirrors depict scenes of Amida Buddha and attending bodhisattvas descending from the Western Paradise to welcome the souls of the faithful — a composition known as raigō (来迎), or "welcoming descent."

On the two Raigō mirror images, Amida Buddha is shown seated in meditation upon clouds, flanked by Kannon (Avalokitesvara) bearing a lotus pedestal and Seishi (Mahasthamaprapta) with hands pressed together in prayer. Rays of light emanate from the Buddha's forehead as the heavenly procession descends over mountain peaks toward the earthly realm. In one of these mirrors, a small building with a hip-and-gable roof appears in the lower corner — likely representing the deathbed chamber of the person being welcomed to paradise.

Art historians praise these mirrors not only as exceptional examples of metalwork but also as valuable pictorial documents. The engraved raigō compositions follow the conventions of contemporary Heian-period Buddhist painting, making them important cross-references for the study of Pure Land Buddhist art. The delicacy and confidence of the engraved lines demonstrate the highest level of craftsmanship available in 12th-century Japan.

Why This Is a National Treasure: The Significance

The designation as a National Treasure reflects the collection's exceptional importance across multiple dimensions. First, the artistic quality of the line-engraved mirrors is outstanding — they rank among the finest examples of Heian-period decorative metalwork in existence, valuable both as masterworks of craftsmanship and as irreplaceable pictorial records of Pure Land Buddhist iconography.

Second, and perhaps most remarkably, the inscriptions on the sutra tubes and colophons on the scrolls reveal that the people who created these sutra mounds were priests of the Ise Grand Shrine — the holiest site of Shinto, Japan's indigenous religion. The 1173 inscription explicitly names an Ise Shrine gon-negi, while analysis of the 1159 materials has identified the involvement of Watarai Masahiko, a senior priest of the Outer Shrine (Gekū), and a nun named Shinmyō, believed to have been his wife who took Buddhist vows. She is thought to have buried the sutras to pray for her husband's rebirth in paradise when he passed away on August 15, 1159 — just one day after the date on the sutra colophon.

This evidence is profoundly significant for understanding the religious history of Japan. It demonstrates that even at the very heart of Shinto practice, Buddhist faith — specifically, Pure Land devotion and Mappō eschatology — had deeply penetrated the lives of shrine officials. The collection thus provides irreplaceable primary evidence for the study of shinbutsu shūgō (神仏習合), the syncretic fusion of Shinto and Buddhism that characterized much of Japanese religious life before the forced separation of the two religions in the Meiji era.

Third, the collection is valuable as an archaeological assemblage. The combination of dated inscriptions, well-preserved sutra scrolls, fine metalwork, imported ceramics, and associated ritual objects provides a rich, contextually intact window into the devotional practices and material culture of 12th-century Japan.

Visiting: Kongōshōji Temple and the Sutra Mound Site

The excavated artifacts are preserved and displayed at the Treasure House (宝物館) within the grounds of Kongōshōji Temple, located near the summit of Mount Asakuma. The temple itself is a deeply rewarding destination — founded in the 6th century, it has served for over a millennium as the spiritual guardian of Ise Grand Shrine's northeastern "demon gate" (kimon). The famous folk song goes: "If you visit Ise, you must also climb Asakuma; without Asakuma, your pilgrimage is only half complete."

The sutra mound archaeological site at Kyōgamine lies on the ridge northwest of the temple's main hall. While the original artifacts have been removed for preservation, stone pagodas now mark each excavation point, creating an atmospheric trail through the forested hillside. The 28 standing stone markers were donated by supporters after the excavation, each with its own distinctive design.

The journey to Kongōshōji is itself part of the experience. The Ise-Shima Skyline toll road winds through the mountains, offering spectacular panoramic views of Ise Bay. Alternatively, adventurous visitors can hike the historic Asakuma-dake pilgrimage trail from the base of the mountain — the same path that Ise pilgrims have walked for centuries.

Surrounding Attractions

A visit to Mount Asakuma can be combined with explorations of several nearby attractions. The Ise Grand Shrine Inner Sanctuary (Naikū) and Outer Sanctuary (Gekū) are the primary pilgrimage destinations in the area, and the charming traditional shopping street of Oharai-machi and Okage Yokochō near the Inner Sanctuary offer local cuisine and souvenirs. The Asakuma Summit Observatory provides sweeping 360-degree views, and the photogenic "Sky Post" (天空のポスト) atop the mountain has become a popular spot. Nearby Toba, accessible via the Ise-Shima Skyline, is famed for its pearl industry and Toba Aquarium. The scenic Meoto Iwa (Wedded Rocks) at Futami are also within easy reach.

Tips for International Visitors

Mount Asakuma and Kongōshōji Temple offer a serene contrast to the crowds at Ise Grand Shrine. English signage is limited at the temple and treasure house, so preparing in advance will enrich your visit. Photography policies at the treasure house should be confirmed on-site. The mountain summit can be significantly cooler and windier than the town below, so bringing a light jacket is recommended even in warm months. If visiting by taxi, arrange for the driver to wait during your visit, as taxis are difficult to summon at the mountaintop.