Hi, this is Ai.
The big summer event here in Ise just wrapped up. The first-phase Okihiki river-pulling — where teams haul sacred timber up the Isuzu River toward Naiku for the next Shikinen Sengu — finished on August 2. The town has gone quiet again, in that pleasant, slightly wistful way it does after a festival. And when things go quiet, Grandpa gets thoughtful.
A few evenings ago he put a thick, plainly bound book on the table and said, “Everything you watched this summer was written down over a thousand years ago. Want to see where?”
The book was a modern printed edition of the Engishiki (延喜式), a legal code compiled by the Heian court in the 10th century. I had heard the name in school, vaguely, the way you hear about tax law. I did not expect it to be the reason my hometown rebuilds its shrine every twenty years. So today I want to write about that: how a ritual became law, and what the law actually says.
A Fifty-Book Law Code from the Heian Court
First, the basics, because I had to learn them myself.
The Engishiki is a collection of detailed regulations — shiki means something like “procedures” or “implementing rules” — that spelled out how the laws of the ritsuryō state were to be carried out in practice. According to the Cultural Heritage Online database maintained by Japan’s Agency for Cultural Affairs, compilation began in 905 at the order of Emperor Daigo, and the finished work was presented to the throne in 927. It then sat through decades of revision before being formally put into effect in 967.
Fifty books. Everything from court banquets to provincial taxes to the exact quantities of silk and sake owed to particular shrines. What surprised me is where the shrine material sits: the first ten books — a full fifth of the entire state code — deal with the affairs of the Jingikan, the office of kami worship. Grandpa says that ordering alone tells you how the Heian court ranked its priorities. Ritual came first, literally.
For Ise, the part that matters most is Book Four, the Ise Daijingū Shiki (伊勢太神宮式) — the implementing regulations for the Grand Shrine of Ise.
Book Four: The Rules for the Grand Shrine
Here is the famous part. Book Four contains a clause that is usually rendered along these lines: the Grand Shrine is to be relocated to a newly built sanctuary once every twenty years, this applying to the main sanctuary, the treasure halls, and the outer offering hall.
I want to be careful here, because I am quoting a Heian legal text through modern editions and commentaries, not reading tenth-century manuscript with my own eyes (Grandpa laughed and said not even he can do that). But the substance is not in dispute: the twenty-year rebuilding interval that Ise still follows today appears in the Engishiki as a written rule, together with the specific buildings it covers. The official site of Jingu describes the system in the same terms — a fixed cycle, fixed in writing, covering not just the main sanctuaries but the halls around them.
And it does not stop at “rebuild every twenty years.” What struck me when Grandpa walked me through the structure of the text is how much of it is inventory. The regulations enumerate the sacred apparel and furnishings to be prepared anew — textiles, weapons, fittings — with quantities and specifications. The rebuilding was never only about architecture. The written rules treat the renewal of the things inside the buildings as part of the same obligation as the buildings themselves.
That is still true in the current, 63rd Sengu. When I wrote earlier about how the twenty-year cycle keeps craft skills alive across generations, I was really describing the long shadow of those inventory lists. A specification written down in the 10th century becomes, a thousand years later, a reason an apprentice weaver or metalworker gets trained. I find that quietly amazing.
Source: Utagawa Kuniyoshi, Wikimedia Commons / Public Domain
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What Was Already Old in 927
Here is the thing that reset my sense of time, though. When the Engishiki was completed in 927, the Sengu was already an old institution.
According to Jingu’s official account of the Shikinen Sengu, the system is traditionally attributed to Emperor Tenmu in the late 7th century, with the first Sengu carried out at Naiku in 690, in the reign of his empress and successor, Jitō. If you accept that traditional dating — and I will flag that the earliest history of the system is studied and debated by scholars rather than something I can verify myself — then by the time the Heian compilers sat down to write Book Four, the twenty-year renewal had been practiced for over two centuries.
There is also an important earlier document. In 804, more than a century before the Engishiki, the shrine itself submitted a detailed report of its rituals and organization to the court — the Kōtai Jingū Gishikichō (皇太神宮儀式帳), often described as one of the oldest surviving records of Ise’s ceremonial life. So the flow of information was not simply “the capital invents rules and Ise obeys.” Ise documented what it already did; the court later fixed a version of it into state law.
Grandpa put it in a way I keep thinking about: the Engishiki did not create the Sengu. It promised it. A practice that depends on memory can fade in a bad generation. A practice written into the administrative law of the state becomes something officials must budget for, provinces must supply timber for, and successors must inherit whether they feel like it or not. Codification is a kind of time capsule with legal force.
Of course, the promise was not unbreakable — the cycle was interrupted for long stretches during the wars of the 15th and 16th centuries before being revived. But the written standard meant there was always a defined thing to revive. The rule outlived the ruptures.
Reading a Legal Code on the Veranda
Now for the part of the evening I actually want to remember.
We sat on the veranda with cold barley tea, and Grandpa opened the book to Book Four and traced the columns of characters with his finger, translating the bureaucratic Chinese-style prose into ordinary Japanese for me. Quantities of cloth. Names of halls. Intervals of years. It is, honestly, extremely dry reading — it is a legal code, after all, not poetry.
But then he pointed out the window, in the general direction of the Isuzu River, and said: “Two weeks ago you stood on the riverbank and watched people pull hinoki logs toward Naiku. Somewhere in the chain of reasons why they were doing that is this page.”
And something clicked for me. The Okihiki teams in their happi coats, the timber sledges, the chanting — none of that is in the Engishiki, at least not in the festive form we see today, which grew up with the townspeople of Ise over later centuries. What is in the Engishiki is the obligation that makes all of it necessary: new buildings, new furnishings, every twenty years, no exceptions contemplated. The festival is the living flesh; the code is the old, quiet skeleton underneath.
I admit I got a little emotional about a tax-code-looking document, which Grandpa found very funny.
The 63rd Sengu Is Following the Same Script
Since this blog is partly my record of the current rebuilding, let me note where things stand as of this writing, August 13, 2026.
The first-phase Okihiki land-pulling events ran through early summer, and the river-pulling (kawabiki) for Naiku was held from late July, concluding on August 2, 2026. Local reporting — including the Chunichi Shimbun’s photo coverage of the opening of the Okihiki events and the schedule published by the Ise Gosengū Committee, the local organizing body — described dozens of neighborhood pulling teams hauling the sacred timber, with the Futami district teams bringing logs up the Isuzu River into the Naiku precincts during the kawabiki days. I wrote about watching part of it myself, and honestly, “hauling government-mandated construction materials” has never looked so joyful.
Seen through the lens of Book Four, this summer’s events were one more installment in a compliance schedule set down eleven centuries ago. The 63rd Sengu began with its opening rites in 2025 and builds toward the Sengyo — the transfer of the deity to the new sanctuary — planned for 2033. Eight years of preparation for one night of quiet procession. The Engishiki’s compilers would recognize the shape of it immediately, even if the crowds with smartphones might puzzle them.
If you are curious why the outer shrine, Geku, has such a prominent place in all of this, my earlier piece on why worship at Ise customarily begins at Geku connects to another part of the same Heian-era textual world.
If You Want to Meet the Engishiki Yourself
A practical note to finish, since I know many of you reading this are planning Ise trips.
You do not need to read Heian legal prose to feel this history. At Geku, the Sengu Museum (Sengūkan) exhibits the craftsmanship of the rebuilding — architectural members, reproductions of the sacred furnishings, the whole material world that the old regulations enumerate. Standing in front of a full-scale reproduction after learning that these objects exist because a 10th-century book says they must — that changes how you look at them. At least it did for me.
And if you visit during a future Okihiki or other Sengu event year, remember: you are not just watching a festival. You are watching a legal obligation, cheerfully honored for a thousand years and counting.
Grandpa says the best laws are the ones people would keep even if the law disappeared. I think Ise proved that one a long time ago.
Thanks for reading — Ai.
Sources and further reading
Primary and official sources:
- Jingū Shichō (Jingu Administration), official Shikinen Sengu pages: What is the Shikinen Sengu and The Thought Behind the Shikinen Sengu (accessed August 13, 2026)
- Agency for Cultural Affairs, Cultural Heritage Online: Engishiki (accessed August 13, 2026)
On the 2026 Okihiki events (status as of August 13, 2026):
- Chunichi Shimbun Web, “伊勢神宮の式年遷宮に向け「お木曳行事」始まる” (photo and video feature on the start of the Okihiki events, 2026; accessed August 13, 2026)
- Ise Gosengū Committee (伊勢御遷宮委員会), official event information at isesengu.jp (accessed August 13, 2026)
Historical claims in this article follow the official Jingu account and standard reference works; where scholarly debate exists (such as the earliest origins of the Sengu system), I have tried to say so rather than pretend certainty.