Nikkō — the one true spelling, and the forms that fail it
A letter to a colleague, 31 July 2026 — on the name Nikkō, and on the forms that keep failing it.
Your note said, roughly: surely the marks are a nicety. Permit me to use Nikkō to show they are not.
First, the attestation. The name is attested as 日光, as Kojiki (foundation myths and kami references) and Nihon Shoki (imperial chronicle to 697 CE) preserve it. On the evidence, it means "Sunlight". The canonical transliteration is Nikkō.
And the marks themselves: o → ō (Macron: long vowel). Remove any one of them and you have not simplified the name — you have told a small lie about it, and the whole discipline is the refusal of such lies.
Say it aloud as the sources heard it: 'NEE-koh' — the first syllable is quick with a soft 'ny' color; hold the final 'koh' long, as if pronouncing two k's in a row. The marks are what carry that sound to a reader who has never heard it spoken.
On the plain form — and I want to be precise, because you pushed on this. The plain form nikko is not false — it is a fallback, and the register is exact about what that means. In systems that cannot carry diacritics (legacy databases, older tooling, parts of the address-bar pipeline) the flattened form is the accepted vehicle, and the rulebook names it explicitly as the final rung of the fallback hierarchy: full restoration first, circumflex where attested, macron-only by the academic standard, an attested variant, and only then plain ASCII.
What the fallback status forbids is promotion: nikko may carry the name where marks are impossible, but it may not represent the name where marks are possible. Every mark it drops — o → ō — is a fact the sources recorded. A fallback is a vehicle, never the primary.
Now to the forms that provoked your letter. As for Nikko: it comes from the publisher compromise — older books and hurried websites that print the "English equivalent" as if it were the name itself, and it fails because every substitution here (ō→o) is a romanization of convenience, not an attested spelling — it teaches the reader to guess, not to read As for Nikkô: it comes from the near-miss — a form that looks right at a glance and circulates on wikis and forums, and it fails because a macron (length) is not a circumflex (quality/tone) — they answer different questions
One more thing, because it always surprises: the name did not stay home. Nikkō is a textbook case of shinbutsu shūgō, the medieval Japanese synthesis of Shinto and Buddhism. Tōshō Daigongen was simultaneously a Shinto kami and a Buddhist avatar; the shrine's architecture borrows from both traditions.
And it never stopped working. Nikkō is one of Japan's most visited sacred sites and a UNESCO World Heritage property. Its autumn maples, snow-covered gates, and the famous proverb Nikkō wo mizu shite kekkō to iu nakare (日光を見ずして結構と言うなかれ — 'don't say «splendid» until you've seen Nikkō') continue to shape Japanese aesthetics.
The Convention's Own History
Every tradition in this register has its own scholarly transliteration standard, built by its own specialists over decades or centuries, and the register follows each on its own terms: Hepburn with macrons — ō and ū marked, never collapsed to o/u or rewritten ou. The principle that unifies them is the one the whole project stands on: a name is evidence, and evidence is not negotiable — not for keyboards, not for convenience, not for anyone.
Where Protocol Meets Practice
The technical answer is simple: the canonical marks are legal IDNA 2008 characters, encoded as punycode under `xn--`. The practical answer is messier: legal does not mean stocked (registrar inventory is partial), and stocked does not mean typeable (stacked diacritics defeat mobile keyboards).
So the register's rule is a hierarchy of attested forms — full restoration, circumflex, macron-only, attested variant, and finally plain ASCII for the systems that cannot carry marks. Every rung is defensible because every rung is attested. The forms this register rules against are not rungs; they are errors, and errors do not get rungs.
Write back when you have checked the sources; they are better company than I am.
— The Register
The Verdict
Nikkō is the canonical form: attested, checkable, and enforced across the temple, the lexicon, the cards, the APIs, and this register. The plain form nikko is sanctioned as the fallback vehicle and nothing more. The false forms above are documented so that no reader has to take the temple's word on faith — the violations are stated, the sources are named, and the register stands open to challenge on every line.
The temple of Nikkō stands at /sites/nikko/.
The docket for this ruling: 2 false forms ruled against, Nikko first on the docket; 1 preserved mark verified: o → ō; no contested forms attested; the attestation rests on 7 cited sources — Kojiki (foundation myths and kami references), Nihon Shoki (imperial chronicle to 697 CE), Tōshōgū engi and Tokugawa-period shrine records.
The Register Continues
This is one of 287 entries in the Canonical Register — the authoritative reference for every flagship temple. The temple's founding dispatch tells the name's story; its Restoration File details the marks; its Resonance File reads the archetype into the industries. The blog index holds the whole archive, and the Rulebook states the convention this register enforces.
Continue the register — previous entry: Níkē (read it) · next entry: Nirmātā (read it).
The Canonical Register is written from the same canonical record as the lexicon itself. If a false form is missing from this page, it is because the evidence does not support calling it false — or because we have not seen it yet. Show us, with a citation, and the register will answer.