神社の結界Sacred Boundaries At Shinto Shrines

The origin of Shinto is said to trace back to the nature worship practices originating in the Jomon period. Even today, there are approximately 80,507 shrines across Japan, surpassing Buddhist temples in number and making them one of Japan’s most numerous religious and cultural architectural forms. The majority of these shrines are managed by local residents, with only around 20,000 shrines having a permanent Shinto priest. In reality, it is common for one priest to manage several shrines concurrently. Through my own extensive travels and research, having visited numerous shrines nationwide, I have frequently experienced stepping into shrine precincts and immediately being enveloped in an atmosphere distinctly more solemn and sacred than everyday spaces. It’s a curious sensation, but at especially auspicious shrines, merely passing through the torii gate (鳥居) changes the air into a state of complete purity, gently heightening spiritual responsiveness. When visiting particularly special shrines, I deliberately visit in the early morning and, following ancient customs, abstain from eating meat (particularly four-legged animals) for at least three days prior to the visit.

This unique sensation, challenging to fully convey through words, arises from what is known as a “kekkai” (結界), an invisible spiritual boundary established at shrines. Originally a Buddhist term, kekkai signifies the boundary separating a “sacred area” (聖域) from the “profane world” (俗世). Similarly, at Shinto shrines, structures such as torii gates, sacred ropes known as shimenawa (注連縄), and fences called tamagaki (玉垣) physically demarcate this boundary, thus creating a distinctly “holy space.”

At the root of Shinto is nature worship, which venerates mountains, forests, rocks, and ancient trees themselves as divine entities. Numerous ancient legends remain across Japan, calling mountains inhabited by deities “Kannabi” (神奈備), and sacred rocks “Iwakura” (磐座), though originally these distinctions did not exist, with the entire area considered sacred. Since ancient times, before shrine buildings existed, specific mountains or forests were revered as “holy spaces,” treated with reverence and carefully avoided by people. Although the precise origins of shrine architecture remain unclear, archaeological insights point to connections with Yayoi period ritual buildings and raised-floor storehouses. Later, influenced by Buddhism’s arrival in Japan, Shinto-related clans began constructing shrines explicitly as the new forms of temples and statues spread with Buddhism.

Consequently, it is challenging to discern primitive nature worship elements within contemporary shrines. Yet, at the renowned Omiwa Shrine in southern Nara Prefecture, the mountain behind the shrine, Mount Miwa, is still directly worshipped as the deity itself, without a main shrine building, exemplifying an ancient form of nature worship. I myself visit Omiwa Shrine several times each year. Such shrines aren’t limited to Omiwa Shrine alone but can be found among ancient shrines. The notion of regarding nature itself as divine, predating the establishment of structured Shinto, embodies the foundational philosophical mindset of Japanese culture. Philosopher Takeshi Umehara, who significantly influenced the study of ancient Japanese history, pointed out that at the core of Japanese spiritual culture lies a “Forest Thought” that deeply respects harmony between humans and nature and values the cycle of life. The establishment of shrines thus expresses reverence for the myriad spirits of nature (森羅万象), and one can only grasp the essence of Shinto by understanding these deeper ancient layers.

Among shrine elements, the torii gate serves as a symbolic representation of kekkai, standing at the entrance to the shrine as a symbolic boundary separating the divine realm from the human world. Passing through the torii at the start of the approach path symbolizes stepping from the ordinary into sacred territory. Consequently, when Japanese people visit shrines, it is customary to bow once in front of the torii gate before entering, carefully avoiding walking through the center of the path, as it is reserved for the kami. The area within the torii represents the pure, sacred space called “shin’iki” (神域), while beyond it extends the mundane, everyday world. At first glance, this may appear merely a simple structural division of space, but for Japanese visitors, it clearly communicates the understanding that “beyond this point lies a special place,” naturally prompting them to straighten their posture and sense the inherent sanctity.

Next, at shrine precincts such as the main hall (本殿), sacred trees (御神木), and sacred rocks known as “Iwakura”, you will see sacred ropes called “Shimenawa”. Today, shimenawa typically consists of rice-straw ropes with lightning-shaped paper streamers known as “Shide” (紙垂), but until before World War II, they were predominantly made from hemp. Shimenawa not only serves as a boundary marking the sacred space inhabited by deities from the external world but also holds spiritual functions, protecting the deity’s territory from evil spirits and impurities. Thus, placing a shimenawa visually communicates the message: “Within this boundary is a pure, sacred space, protected from impurity and evil,” prompting visitors to adopt a reverent attitude as they offer their prayers. Until the early Heian period, shimenawa was referred to as “Shirikumenawa” (斯利久迷縄), and according to the “Kogo Shui” (古語拾遺, 807 AD), it was also called “Hikage no Katachi” (日影の像). Even older mythological records describe it as “Hi no Mitsuna” (日御綱), illustrating that the belief in spiritual boundaries dates back to Japan’s mythological era.

In addition, shrines feature fences known as “Tamagaki”, particularly surrounding the innermost sanctuary, clearly separating the divine inner space from the external world. Outside the Tamagaki lies the secular world inhabited by humans, while the space within is a sacred area reserved for deities. The number of fence layers varies depending on the shrine’s scale; for example, the Inner Shrine (内宮) of Ise Grand Shrine has four layers of fences, with the innermost layer named “Ichi no Tamagaki” or “Mizugaki” (一の玉垣・瑞垣). Each successive layer heightens the sacredness, creating an intriguing spatial hierarchy. Originally, Tamagaki were hedges composed of densely growing Sakaki trees (榊), a sacred evergreen tree whose Japanese kanji explicitly combines “tree” (木) and “deity” (神). Thus, sakaki trees have long been essential in Shinto rituals. The physical barrier formed by Tamagaki guards the invisible spiritual core of the shrine, firmly serving as a kekkai. At the same time, it silently communicates to observers, “Beyond this point lies another world,” inspiring reverence and respect toward the sacred space.

In this way, the kekkai found at shrines does not merely function as a practical division of space but embodies the Japanese religious worldview that distinguishes the sacred from everyday life, a perspective that dates back to ancient times. Religious scholar Minoru Sonoda discussed the role of shrines within village communities, emphasizing how torii gates placed at village boundaries served as “kekkai devices,” preventing disasters and impurities from entering from the outside world. This suggests kekkai acted as spiritual fortifications protecting communities, evoking the importance ancient Japanese placed on spiritual battles against unseen threats. Furthermore, the space demarcated by the kekkai also serves as a site for encounters with the divine. Philosopher Tetsuro Watsuji, reflecting on the relationship between nature and humanity, highlighted how shrine spaces provide opportunities for ethical reflection and self-transcendence.

Moreover, contemporary religious philosophers such as Shogo Tani and Toji Kamata have pointed out that shrine spaces simultaneously separate and connect the concepts of “Hare and Ke” (ハレとケ), or sacred and profane worlds. Within shrines separated from the secular realm by kekkai, visitors encounter an extraordinary sacredness, gaining opportunities for spiritual purification. Thus, the concept of kekkai embedded in Japanese shrine architecture richly encapsulates reverence for nature, the dichotomy of sacred and profane, and the profound communion between humans and deities.