On the banks of the Isuzu River in Ise City, Mie Prefecture, stands Kotai Jingu, better known as Naiku, the Inner Shrine of Ise Jingu. Here Amaterasu-Omikami, the sun goddess revered as the ancestral deity of the Imperial family, is enshrined. Many visitors know her from the myth of the Heavenly Rock Cave, where her withdrawal plunged the world into darkness; this article asks a different question: why did she come to be worshipped here, in a quiet forest far from the old capitals?
LEGEND: Yamatohime-no-mikoto’s Search for a Home
LEGEND: What the Nihon Shoki tells
According to the Nihon Shoki (720), the sacred mirror representing Amaterasu was originally kept inside the imperial palace. During the reign of Emperor Sujin it is said to have been moved out of the palace and entrusted to Princess Toyosukiirihime. Under Emperor Suinin, the role passed to his daughter, Yamatohime-no-mikoto, who set out to find a place where the goddess would wish to dwell. According to Ise Jingu’s own account, she travelled through Yamato, Iga, Omi and Mino before reaching the upper Isuzu River at Uji in the Watarai district of Ise; later traditions name further stops, such as Owari.
The Nihon Shoki records that the goddess then spoke to her, describing Ise as a land where the waves from the eternal world of Tokoyo roll in, a secluded and beautiful province where she wished to stay. A shrine was then established by the Isuzu River. These events belong to the realm of tradition and court chronicle: historians do not treat the dates literally, and the actual origins of worship at Ise remain a matter of scholarly debate. Many places along the route, known as Moto-Ise, claim in local tradition to be temporary resting sites of the goddess.
LEGEND: The Yata no Kagami
Tradition holds that the object of worship (goshintai) at Naiku is the Yata no Kagami, the sacred mirror that is one of the Three Sacred Treasures of the Imperial Regalia. In myth, the mirror is linked to Amaterasu herself and is said to have been handed down from the age of the gods. The mirror is never shown to the public, and no one outside a very small circle of priests has seen it; its form and age therefore cannot be verified. What can be said as fact is that Ise Jingu describes Naiku as the shrine of Amaterasu-Omikami, and that the mirror’s presence there is a long-held tradition rather than something open to inspection.
FACT: Rebuilding Every 20 Years – Shikinen Sengu
FACT: What the records say
Ise Jingu rebuilds the main sanctuaries of Naiku and Geku, along with many related structures and sacred treasures, on an adjacent plot roughly every 20 years, and the deity is transferred to the new hall. This ceremony is called Shikinen Sengu. According to the shrine, it has continued for about 1,300 years; the shrine dates the first Sengu to the fourth year of Empress Jito’s reign (690). The 62nd Sengu took place in 2013, and the shrine’s official site states that the 63rd Shikinen Sengu is being carried out over a period of more than eight years beginning in Reiwa 7 (2025).
Because of this cycle, two sites sit side by side within the precinct: the current sanctuary and the empty plot where the next one will stand. Visitors can sometimes see both. Why 20 years was chosen is not explained in early records; common explanations, such as passing on carpentry skills between generations or keeping the shrine eternally fresh, are later interpretations rather than documented reasons, and should be read as such.
FACT: Uji Bridge
The approach to Naiku begins at Uji Bridge, a wooden bridge 101.8 metres long spanning the Isuzu River, with a large torii at each end. It is regarded as the boundary between the everyday world and the sacred precinct. The bridge is also rebuilt in step with the Sengu cycle, and, according to Ise Jingu, the inner torii is made from the munamochi-bashira (ridge-supporting pillar) of the former Naiku main sanctuary, and the outer torii from that of the former Geku main sanctuary. Ise City’s tourism association notes that around the winter solstice, the sun can be seen rising through the torii of Uji Bridge.
FACT: Visiting Naiku Today
FACT: Purification at the Isuzu River and etiquette
Inside the precinct, beside the temizusha basin, visitors can descend stone steps to the Isuzu River at the Mitarashi and rinse their hands in the river itself. Ise Jingu explains that washing the hands and mouth is a simplified form of misogi purification. The shrine’s recommended manner of prayer is two bows, two claps and one bow. The official site also asks visitors to keep to the right at Naiku (left at Geku), not to smoke or eat inside the sacred grounds, and not to bring pets. Ise Jingu restricts photography in parts of the precinct, including designated no-photography areas such as around the main sanctuary; please follow on-site signs and staff.
FACT: Naiku and Geku
Ise Jingu is not a single shrine but a complex of 125 shrines centred on two main sanctuaries. Naiku enshrines Amaterasu-Omikami, while Geku (Toyouke Daijingu), about 4–5 km away (around 10–20 minutes by bus or taxi), enshrines Toyouke-no-Omikami, the deity of food who provides offerings to Amaterasu. Ise Jingu says there is no fixed rule, but visiting Geku first and then Naiku is a long-standing custom. There is no admission fee (per Ise City Tourism Association).
Visiting hours for Naiku, Geku and the betsugu (per isejingu.or.jp): January–April and September 5:00–18:00; May–August 5:00–19:00; October–December 5:00–17:00. Hours change during the New Year period. Access: buses run to the Naiku-mae stop from Iseshi and Ujiyamada stations (about 20 minutes, per Ise City tourism). Times and routes can change, so please check the official site before you go.
Sources
- 伊勢神宮 Ise Jingu Official Site
- ご参拝・ご祈祷 | 伊勢神宮 (visiting hours)
- 参拝の作法とマナー | 伊勢神宮
- 内宮（皇大神宮） | 伊勢神宮
- 正宮 皇大神宮 | 伊勢神宮
- 宇治橋・五十鈴川 | 伊勢神宮
- 式年遷宮 | 伊勢神宮
- よくあるご質問 | 伊勢神宮
- よくある質問 | 伊勢市観光協会
- Ise Jingu / Naiku | Ise City Tourism Association
- Ise Jingu (Naiku) | Visit Iseshima (official Ise-Shima tourism)
- Yamatohime-no-mikoto | Wikipedia
- Ise Grand Shrine | Wikipedia
- 倭姫命 | Wikipedia
- 八咫鏡 | Wikipedia
To explore further, visit Oni Kobo (鬼工房) for onigawara demon-tile art and charms and Onigawara Experience for hands-on onigawara experiences in Japan.
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