When an international word comes into Ukrainian, how do you know whether it is spelled with и or with і? Is it систе́ма or сістема, ри́тм or рітм, хі́мія or химія? The answer is one of the most-drilled rules in Ukrainian orthography: the «правило дев’ятки», the rule of nine. It is a single, learnable test that fixes the spelling of hundreds of borrowed words, and it is one of the sharpest dividing lines between Ukrainian and Russian spelling. Master the nine consonants and the "next letter" test, and a whole category of spelling stops being guesswork. (For the native-word и/і rules, see і vs и spelling; this page is specifically about borrowings.)
The nine consonants and the mnemonic
The "nine" are: д, т, з, с, ц, ч, ш, ж, р. Generations of Ukrainian pupils memorise them through the sentence:
«Де ти з’їси цю ча́шу жи́ру?»
'Where will you eat this bowl of fat?' — the mnemonic: the initial consonants Д-Т-З-С-Ц-Ч-Ш-Ж-Р are exactly the nine.
Read the first letters: Де ти з’їси цю чашу жиру — д, т, з, ц, ч, ж, р — and с and ш fall out of the same phrase. Whatever mnemonic you use, the job is to have those nine consonants instantly available.
Write и: after the nine, before a consonant
When a borrowed word has one of the nine consonants followed by another consonant, write и:
систе́ма
system — с + и, next letter с (consonant).
дисциплі́на
discipline — both д+и and (after the л) і; the FIRST и follows д before с.
дире́ктор
director, principal — д + и, next letter р.
ри́тм
rhythm — р + и, next letter т.
ци́фра
digit, figure — ц + и, next letter ф.
ци́рк
circus — ц + и, next letter р.
режи́м
regime, mode — ж + и, next letter м.
ши́фр
cipher, code — ш + и, next letter ф.
ти́тул
title (rank, heading) — т + и, next letter т.
такси́ст
taxi driver — с + и, next letter с.
У ме́не на робо́ті суво́ра дисциплі́на й чітки́й режи́м дня.
At my job there's strict discipline and a clear daily routine.
Дітвора́ обожнює ци́рк — особли́во кло́унів.
The kids adore the circus — especially the clowns.
Note дисциплі́на carefully: it has both letters. The и after д is the rule of nine (д before с); the і later (after the л) is just an ordinary і, because л is not one of the nine. One word, both letters, each in its right place.
Write і/ї: everywhere else in a loanword
The rule of nine is a narrow exception. Everywhere it does not apply, a borrowing keeps і (or ї). Three situations cover the rest.
After any consonant that is NOT one of the nine, write і:
хі́мія
chemistry — х is not one of the nine, so і (not и).
кіло́
kilo, kilogram — к is not one of the nine, so і.
бі́знес
business — б is not one of the nine, so і.
архі́в
archive — х is not one of the nine, so і.
кіно́
cinema, the movies — к is not one of the nine, so і.
Before a vowel, an apostrophe, or ь, write і/ї even after one of the nine — because the "next letter consonant" test fails:
ра́діо
radio — д is one of the nine, BUT the next letter is the vowel о, so і.
тріа́да
triad — р is one of the nine, BUT і stands before the vowel а, so і.
діа́гноз
diagnosis — д before the vowel а, so і.
At the end of a word, write і:
таксі́
a taxi — word-final, so і (contrast такси́ст, where и stands before с).
спіч
a speech (a short formal address, e.g. a toast) — і before the final ч; not before a consonant cluster, so і.
So the same root family can show both letters depending on what follows: таксі́ (final, і) but такси́ст (before с, и).
The contrasting pairs to lock it in
| и (rule of nine fires) | і (rule does not fire) |
|---|---|
| систе́ма (с before с) | хі́мія (х not in the nine) |
| ри́тм (р before т) | кіно́ (к not in the nine) |
| дире́ктор (д before р) | бі́знес (б not in the nine) |
| такси́ст (с before с) | таксі́ (word-final) |
| режи́м (ж before м) | ра́діо (д before a vowel) |
Honest caveats: where it gets messy
The rule of nine is clean, but its scope is "common foreign words." Two areas behave differently and you should not over-apply the rule.
Proper names and geographic names often follow their own conventions and frequently keep і even after one of the nine — though usage varies and some are fixed by tradition:
Чика́го
Chicago — a place name; spelled with и here after ч, but proper names are a special category you should check case by case.
Сінгапу́р
Singapore — keeps і after с (a proper name following its own convention).
Recent anglicisms and very new borrowings can vary while usage settles; when in doubt for a freshly borrowed term, check a current dictionary rather than trusting the rule alone.
A note on the related е/є rule
Borrowings also choose between е and є. Briefly: after a vowel or at the start of a word a borrowing usually takes є where a /j/ or softening is heard (Євро́па, проє́кт), and е after a hard consonant (систе́ма, тенде́нція). This is a separate rule from the rule of nine; mentioning it here only so you do not confuse the two — the rule of nine governs и/і, not е/є.
Source-language comparison
For English speakers the rule has no analogue at all — English keeps the spelling of "system," "rhythm," "discipline" with the same letters everywhere, so the idea that the next consonant decides which i-letter you write is new. The upside is that it is genuinely mechanical: unlike English spelling, the rule of nine actually predicts the answer.
Against Russian, this is one of the loudest differences. Russian writes и in these borrowings far more broadly (and has no "rule of nine"): Russian химия vs Ukrainian хі́мія; Russian кино vs Ukrainian кіно́; Russian бизнес vs Ukrainian бі́знес. A Russian-trained instinct will reach for и after к, х, б — which is exactly where Ukrainian wants і. The shared ground is words like систе́ма / ри́тм / режи́м (и in both), but you must actively withhold и after consonants outside the nine.
Common Mistakes
❌ сістема, рітм, діректор (і after the nine before a consonant)
Incorrect — after д т з с ц ч ш ж р before a consonant, write и: систе́ма, ри́тм, дире́ктор.
✅ систе́ма, ри́тм, дире́ктор
system, rhythm, director.
❌ химія, кино, бизнес (и after a non-nine consonant)
Incorrect — х, к, б are not among the nine, so write і: хі́мія, кіно́, бі́знес.
✅ хі́мія, кіно́, бі́знес
chemistry, cinema, business.
❌ радио, тріада→ ра́діо (и before a vowel after one of the nine)
Incorrect — before a vowel the rule does not fire, so і: ра́діо, тріа́да.
✅ ра́діо, тріа́да
radio, triad.
❌ таксы, такси (final letter wrong)
Incorrect — word-finally write і: таксі́; only before a consonant does the noun take и: такси́ст.
✅ таксі́, такси́ст
taxi, taxi driver — і word-final, и before с.
❌ Applying the rule to a name: Сингапур
Be careful — proper/place names follow their own conventions; the standard form is Сінгапу́р with і, not blanket и.
✅ Сінгапу́р
Singapore — proper name, keeps і.
Key Takeaways
- The rule of nine: after д т з с ц ч ш ж р, before a consonant, in a common loanword → write и (систе́ма, ри́тм, дисциплі́на, ци́рк, режи́м, ши́фр).
- Everywhere else in a borrowing → і/ї: after any other consonant (хі́мія, кіно́, бі́знес), before a vowel/ь/apostrophe (ра́діо, тріа́да), and word-finally (таксі́).
- One word can show both: дисциплі́на (и after д, і after л); такси́ст (и) vs таксі́ (і).
- Names and very new borrowings are exceptions — verify them; do not over-apply (Сінгапу́р, Чика́го).
- This rule is a major Ukrainian-vs-Russian divider: Ukrainian хі́мія/кіно́/бі́знес where Russian uses и.
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Start learning Ukrainian→Related Topics
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- Apostrophe Spelling RulesA2 — The spelling-side rules for the Ukrainian apostrophe ’: write it before я ю є ї when a HARD consonant + /j/ glide precedes — after the labials б п в м ф, after hard р, and after consonant-final prefixes — but NOT when the consonant is genuinely soft. Omitting or misplacing it is one of the most common Ukrainian spelling errors.
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- Letters and Their SoundsA1 — A systematic letter-to-sound table for the citation value of every Ukrainian letter — the iotated vowels я є ю ї, the two i-letters (і = /i/, и = /ɪ/), the voiced-h г versus the hard-g ґ, the rough х, and the sounds Ukrainian simply does not have.