Hepburn vs. Kunrei Romaji: Which Should You Type?

Is し written shi or si? Is つ tsu or tu? Both, actually — Japanese has two competing romanization systems, and once you notice the difference you'll see it everywhere: in textbooks, on train station signs, and in what your IME accepts. Here's what each system is, why both exist, and which one you should build your typing habits around.

The two systems in one table

Everything not in this table — ka, mi, ro and the rest — is identical in both systems.

Where each system comes from

Hepburn (ヘボン式) was designed in the 1880s for English speakers, and its guiding principle is: spell it how it sounds. し genuinely sounds like "shi", not "si", so Hepburn writes shi. It's the system you see on passports, street signs, train stations, and in virtually every textbook for foreign learners.

Kunrei-shiki (訓令式) is the official cabinet-ordered system taught in Japanese elementary schools, and its principle is: spell it how the kana grid works. The さ row is s-a, s-i, s-u, s-e, s-o — so し is si, period. It's beautifully systematic and maps perfectly onto Japanese grammar, which is why linguists and schoolteachers like it.

The good news: your IME accepts both

For typing, this debate has a happy ending — every Japanese IME accepts both spellings, plus convenience shortcuts from neither system. Type si or shi; you get し either way. Japanese typists mix freely, often preferring the shorter Kunrei spellings (si is one keystroke less than shi).

Which should a learner type?

Hepburn — at least until your pronunciation is solid. The reasoning:

• It protects your pronunciation. If you type ti for ちa thousand times, some part of your brain starts hearing "tee". Hepburn keeps the sound and the spelling aligned while your ear is still forming.
• It matches what you read. Textbooks, dictionaries, station signs, and romanized names all use Hepburn. Typing the same system you read means one set of spellings in your head, not two.
• It costs nothing later.Hepburn habits don't block the Kunrei shortcuts — once し=shi is unshakable, typing si to save a keystroke is a free optimization, and your IME will quietly accept it.

This is why the romaji hints across this site show Hepburn first (shi, chi, tsu, ji) while the typing engine accepts the Kunrei spellings too — type whichever comes out of your fingers, read the one that matches the sound.

A third player: wāpuro romaji

Typing actually spawned its own informal system, nicknamed wāpuro (word processor) romaji — the set of spellings IMEs accept that belong to neither standard. Long vowels typed letter by letter (ou for おう where Hepburn would write ō with a macron), nn for ん, and the l/x prefix for small kana (ltu → っ) are all wāpuro conventions. So in practice every Japanese typist uses a pragmatic blend: Hepburn or Kunrei consonants, wāpuro mechanics. You will too — it's not cheating, it's the ecosystem.

One habit to start today

Whenever you learn a new word, say it aloud as you type it. The spelling system debate dissolves the moment the sound, the romaji, and the kana fire together — which is exactly what a typing drill does on every keystroke. Start with the kana that differ between the systems: a few rounds of し・ち・つ・ふ・じ words and the Hepburn spellings will feel inevitable. (New to kana typing entirely? Begin with how to type hiragana.)