The Timeless Spirit of Sustainability Inherited by Ise Jingu

Affectionately known as “O-Ise-san,” Ise Jingu in Ise City, Mie Prefecture, is a revered Shinto shrine widely recognized throughout Japan. For over 1,300 years, a sacred tradition has been passed down at this historic site — the Shikinen Sengu. This ritual, held once every 20 years, involves the complete reconstruction of the shrine’s buildings, with the 63rd iteration set to take place in 2033. Embedded in this practice is the Japanese philosophical concept of “Tokowaka”, a principle that emphasizes remaining perpetually fresh while preserving traditional forms. This idea resonates deeply with modern sustainability ideals. What significance did our ancestors find in the Shikinen Sengu, and what compelled them to uphold this tradition across countless generations? By tracing the essence of this enduring custom, we may uncover valuable insights that could guide us in building a sustainable, circular society rooted in Japan’s cultural wisdom.

Ise Jingu’s Greatest Sacred Ritual, an Eight-Year Endeavor

The Shikinen Sengu is a sacred ritual that has been faithfully carried out at Ise Jingu for centuries. The term “Sengu” refers to the act of “relocating the deity from the old sanctuary to a newly constructed one,” while “Shikinen” means “a fixed, designated year.” Despite its 1,300-year history, the exact reason why this ritual began remains a mystery to this day. However, Kiyomi Chikusa, an author who has written extensively about Ise Jingu, suggests that “examining the historical context may offer some clues.”

Chikusa

The Shikinen Sengu was institutionalized under the initiative of Emperor Tenmu. At the time, Chinese culture was rapidly flowing into Japan and the nation was undergoing significant upheaval. Amid this turbulent period, the question arose: What could be done to unify the country? The answer that emerged may well have been the Shikinen Sengu — a national project designed to achieve that purpose.

The Shikinen Sengu can be described as a kind of “divine relocation.” While this may sound simple, the preparations are remarkably extensive. In addition to constructing a new main sanctuary, around 170 structures — including auxiliary shrines and torii gates — are rebuilt in their entirety. The preparation period alone spans eight years, during which more than 30 sacred rituals and ceremonies take place.

Among the many sacred rituals, one that Kiyomi Chikusa recalls as being “particularly memorable” is the Misomahajime-sai, the ceremony marking the first cutting of timber for the new sanctuary. The hinoki cypress felled during this ritual is used to craft the vessel that houses the sacred object of worship.

Chikusa

There was a small branch from the tree’s crown placed on the stump of the felled tree. Curious, I asked the Somagashira (head woodsman) about it, and he explained, “Since we have taken a tree from the mountain, this is a gesture of gratitude to the mountain deity.” Realizing that this deep-rooted Japanese reverence for nature continues to be passed down to this day truly moved me.

Embodying the Spirit of “Tokowaka” by Intentionally Using Fragile Materials

Compared to ancient landmarks like the Parthenon in Greece or the Pyramids of Egypt, the sanctuaries of Ise Jingu appear strikingly simple and unassuming. The primary materials used for the main sanctuary are hinoki cypress and kaya (a type of thatch), and the architectural style follows the “Yuiitsu Shinmei-zukuri” design, which evolved from traditional raised-floor granaries. The wooden structures are left in their natural state as shiraki (unfinished wood), and the thatched roof resembles an inverted open book. Moreover, unlike the Parthenon or the Pyramids, no foundation stones are laid beneath the structure; instead, the supporting pillars are embedded directly into the ground in a hottate-shiki (earth-set post) style. In contrast to the imposing permanence of other ancient monuments, Ise Jingu's simplicity may even strike some as fragile or fleeting.

Using materials with limited durability, the structures are repeatedly rebuilt, dismantled, and rebuilt again. At first glance, this may seem like a labor-intensive and inefficient process. However, this cycle embodies a profound concept known in Shinto as “Tokowaka”, a special spiritual principle that holds deep significance.

Chikusa

“Tokowaka” refers to a state of perpetual youthfulness. However, it’s not about physical age — rather, it signifies a spirit that remains ever fresh and vibrant. By enshrining the deity in a newly built sanctuary, the belief is that the divine presence is renewed and empowered. I believe this intention lies at the heart of the practice. Additionally, just as a shrine’s daily routine begins with cleaning, Shinto places great value on maintaining a pure and unblemished space. This reverence for cleanliness may also be closely tied to the concept of Tokowaka.

The Shikinen Sengu ritual once faced the threat of discontinuation during the turbulent Sengoku period. After a hiatus of approximately 130 years, it was revived in the Azuchi-Momoyama period. Later, although postponed for four years due to the impact of World War II, the ritual has continued uninterrupted to this day.

Chikusa

It’s truly impressive that the Shikinen Sengu was successfully revived after being suspended for over a century. However, it seems that even during the period of interruption, they managed to sustain the tradition by conducting temporary enshrinements and carrying out repairs and maintenance as needed.

Even with periods of interruption, the fact that this ritual has continued unbroken for 1,300 years is truly remarkable — a unique and noteworthy achievement in the history of human civilization. Why, then, did our ancestors place such profound importance on the act of rebuilding?

Chikusa

It’s difficult to put into words… but for me, I felt I grasped the essence of the Shikinen Sengu during the Ujibashi Watarihajime-shiki — the ceremony marking the crossing of the newly rebuilt Uji Bridge, which leads to the Inner Shrine and is reconstructed as part of the Shikinen Sengu. When I crossed the freshly built Uji Bridge, I was enveloped by the gentle scent of wood, and it felt as though my heart had been purified. The air was crisp and clear, filling the surroundings with a refreshing atmosphere that naturally brought a smile to my face. I imagine that this uplifting feeling — the sense of renewal and positivity that arises when encountering something new — must have resonated deeply with people in the past as well.

The structures of Ise Jingu are built with the promise of being reborn 20 years later. This continuity itself is the embodiment of “Tokowaka”, reminding us that the past, present, and future are all connected in an unbroken cycle.

While this concept may seem solemn and profound, it’s actually quite relatable when we look at everyday life. For instance, cherry blossoms bloom, fall, and then return the following year just as beautifully. Similarly, rice fields are harvested, then replanted with new seedlings, leading to the next fruitful season. This continuous cycle — where the old gives way to the new — is the very essence of the “Tokowaka” spirit.

The Long History of Ise Jingu: Interwoven with the Cycle of Water

The rebuilding process of the Shikinen Sengu requires approximately 13,000 hinoki cypress trees as sacred timber. Each tree is carefully selected by Jingu Gishi (Ise Jingu’s master craftsmen) and is of the highest quality. These trees are then milled into various components, both large and small — an astonishing total of around 100,000 pieces.

Chikusa

The construction process employs a traditional technique known as “Kigumi”, a method of joining wood pieces together like a puzzle, with minimal use of nails. This approach not only simplifies dismantling but also allows for a trial assembly before the final construction of the main sanctuary. In a way, this technique can be seen as an early form of recycling, designed to facilitate the reuse of materials.

The old materials from dismantled buildings are reused as much as possible. For example, the thick pillars from the main sanctuaries of the Outer Shrine (Geku) and Inner Shrine (Naiku) are repurposed as torii gates for Uji Bridge. Twenty years later, these torii gates are further reused — one becoming the torii at Shichiri no Watashi in Kuwana City, Mie Prefecture, and the other at Seki no Oiwake in Kameyama City, Mie Prefecture.

Chikusa

Ise Jingu has been practicing recycling and sustainability for over a thousand years. Visiting shrines that have inherited these reused materials is one of the enjoyable aspects of the experience. Given my line of work, I often visit shrines for research, and each time, I find myself investigating their connections to Ise Jingu.

Kiyomi Chikusa further remarks, “The history of Ise Jingu is deeply intertwined with the concept of circulation.” A symbolic representation of this idea is the Miyuiki Forest, which extends behind the shrine's sanctuaries. This vast expanse of woodland is large enough to encompass the entire Adachi Ward in Tokyo and covers one-fourth of Ise City. Many areas within the forest are off-limits, including sacred zones that remain untouched. This preserved environment has fostered a rich and diverse ecosystem.

When rain falls on the Miyuiki Forest, the water seeps into the soil and eventually flows into the Isuzu River, a first-class river. The river’s currents carry minerals downstream into Ise Bay. From there, the evaporated seawater forms rain clouds that once again nourish the Miyuiki Forest. Leveraging this natural water cycle, Ise Jingu cultivates rice, vegetables, and other crops — a practice that beautifully reflects the harmony between the shrine and its environment.

Chikusa

The offerings dedicated to the deities, such as rice and vegetables, are essentially self-sufficient. Additionally, seafood harvested from Ise Bay is also presented before the divine. This is why preserving the forests and waterways is essential for sustaining these sacred rituals.

Ise Jingu has been actively preserving and managing the Miyuiki Forest to achieve self-sufficiency in producing hinoki cypress for sacred timber. While the forest originally supplied the necessary wood, its resources eventually became depleted, prompting the shrine to source timber from the Kiso mountains (spanning Gifu and Nagano prefectures) from the Edo period onward.

In 1923, the Jingu Forest Management Plan was established to restore and cultivate hinoki from scratch. However, it takes approximately 200 years for these trees to mature into timber suitable for the shrine's pillars. Currently, the project has reached its halfway point, with regular thinning and replanting efforts underway.

With 100 years remaining until completion, this endeavor stretches far beyond the lifespan of a single generation — or even two. Those planting seedlings today will never witness the project's final outcome. Moreover, only a small portion of the saplings will grow into timber of suitable quality.

Just as people a century ago entrusted their efforts to the future by planting trees, today’s work will lay the foundation for a forest that will thrive 100 years from now.

The Shikinen Sengu, which embodies the unique value of “changing to remain unchanged,” and the continuous cycle of nature — both are grand mechanisms that create purity and resonate deeply with one another. Reflecting on this connection adds greater weight to Kiyomi Chikusa’s words: “Nature itself is the very foundation of Ise Jingu.” The fact that the Shikinen Sengu has been carried on for over 1,300 years suggests that our ancestors must have found a profound sense of harmony with nature in this practice — one that brought them a universal sense of reassurance.

The “Tokowaka” spirit, passed down through generations, holds renewed significance in today’s world, where a shift toward a circular society is increasingly essential. As a uniquely Japanese philosophy and practice, it continues to shine ever brighter, offering timeless wisdom for the future.

Kiyomi Chikusa

Born in Tsu City, Mie Prefecture. After working as a news assistant for NHK Tsu’s 630 News and serving as the editor-in-chief of the regional magazine Ise Shima, she transitioned to a career in writing. Chikusa is actively engaged in lectures and writing about Japanese culture, including Ise Jingu, traditional festivals, and seasonal customs. For eight years, she contributed the series “Ise, the Eternal Sacred Land” to the Shinkansen onboard magazine Monthly Hitotoki.