který: The Main Relative Pronoun | Czech Grammar

Který is the single most useful relative pronoun in Czech — the everyday word for which, that, who, and whose when you attach a clause to a noun: the man who lives here, the book that I'm reading, the house I live in. It also does double duty as the interrogative which?. The whole word declines like a hard adjective, so if you already know mladý, you already know který. The one genuinely new idea is its two-part agreement, and getting that right is what this page is for.

The full paradigm: declines like mladý

Který follows the hard adjective pattern exactly. Compare it cell-for-cell with the hard adjective mladý and you will see they are the same shape.

Case	Masc. anim.	Masc. inanim.	Feminine	Neuter
Nominative	který	který	která	které
Genitive	kterého	kterého	které	kterého
Dative	kterému	kterému	které	kterému
Accusative	kterého	který	kterou	které
Locative	kterém	kterém	které	kterém
Instrumental	kterým	kterým	kterou	kterým

And the plural:

Case	Masc. anim.	Masc. inanim.	Feminine	Neuter
Nominative	kteří	které	které	která
Genitive	kterých	kterých	kterých	kterých
Dative	kterým	kterým	kterým	kterým
Accusative	které	které	které	která
Locative	kterých	kterých	kterých	kterých
Instrumental	kterými	kterými	kterými	kterými

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You do not have to memorize a new table. Take any hard adjective ending you know and put kter- in front: mladého → kterého, mladou → kterou, mladým → kterým.

The two-part agreement: the heart of the matter

This is the rule that defines Czech relative clauses, and it is unlike anything in English. Který takes:

its gender and number from the antecedent — the noun it points back to;
its case from its own role inside the relative clause.

These two sources are independent. The antecedent sets the gender/number; the verb or preposition inside the relative clause sets the case. So you choose the form by answering two separate questions: What is the noun it refers to? (gender + number) and What job does který do in its own clause? (case).

Watch the case change while the gender stays fixed. The antecedent žena is feminine singular throughout, but the case shifts with the role:

To je žena, která bydlí vedle nás.

That's the woman who lives next door. (která = subject → nominative)

To je žena, kterou jsem včera potkal.

That's the woman whom I met yesterday. (kterou = object of potkal → accusative)

To je žena, které jsem půjčil knihu.

That's the woman to whom I lent a book. (které = indirect object → dative)

To je žena, o které jsem ti vyprávěl.

That's the woman I told you about. (o které = after the preposition o → locative)

In all four, která / kterou / které / o které are feminine singular (from žena), but the ending tracks the case demanded inside the clause. Master this seesaw and you have mastered the pronoun.

Where antecedent gender and clause case visibly diverge

The cleanest way to feel the rule is to line up examples where the two pulls obviously point in different directions.

Kniha, kterou právě čtu, je napínavá.

The book I'm reading right now is gripping. (kterou: feminine from kniha, accusative as object of čtu)

Muž, kterého jsi viděl, je můj soused.

The man you saw is my neighbour. (kterého: masculine animate from muž, accusative as object of viděl)

Auto, které stálo před domem, už odjelo.

The car that was parked in front of the house has already left. (které: neuter from auto, nominative as subject)

Studenti, kteří složili zkoušku, dostali certifikát.

The students who passed the exam got a certificate. (kteří: masculine-animate plural from studenti, nominative as subject)

Notice kterého in the second example: because muž is masculine animate, its accusative borrows the genitive ending — just as the noun itself would (vidím muže, vidím kterého). This is the same animacy logic that runs through the whole case system, now applied to the relative pronoun.

After prepositions

When který's role inside the clause is governed by a preposition, the preposition comes immediately before it and dictates the case. The gender/number still comes from the antecedent.

To je dům, ve kterém jsme bydleli jako děti.

That's the house we lived in as children. (ve kterém: masculine from dům, locative after ve)

Firma, pro kterou pracuji, sídlí v Brně.

The company I work for is based in Brno. (pro kterou: feminine from firma, accusative after pro)

To je člověk, na kterého se můžeš spolehnout.

That's a person you can rely on. (na kterého: masculine animate from člověk, accusative after na)

Most, přes který jsme šli, je velmi starý.

The bridge we walked across is very old. (přes který: masculine inanimate from most, accusative after přes)

Note that, unlike English, Czech never strands the preposition at the end of the clause — the house we lived in becomes dům, ve kterém jsme bydleli, with ve pulled up front next to kterém. The preposition and the pronoun always travel together.

The interrogative use: which?

Outside of relative clauses, který is also the question word which (one)? — used when you are picking from a known, limited set (as opposed to jaký, what kind of?, which asks about quality; see jaký vs který). As a question word it still declines normally for its role in the question.

Který svetr si vezmeš, ten modrý, nebo ten šedý?

Which sweater will you take, the blue one or the grey one?

Ve kterém patře bydlíš?

Which floor do you live on?

Kterého kandidáta budeš volit?

Which candidate are you going to vote for?

A note for English speakers

English collapses an entire system into a handful of words. Who, whom, which, that barely inflect, and casual English drops the relative word altogether (the book I read). Czech does the opposite: it (almost) never drops the relative pronoun, and it forces you to spell out, in the ending, both whose noun it refers to and what job it does. The instinct to import English habits produces two predictable errors — picking the case from the antecedent instead of from the clause, and trying to leave který out the way English leaves out that. Czech requires it, comma and all. For the comma rule and the confusion with the demonstrative ten, see Common Mistakes: ten versus který, and for when to reach for jenž or co instead, see Choosing a Relative Word.

Common Mistakes

1. Taking the case from the antecedent instead of the clause. The classic error: the antecedent is a subject, so the learner makes který nominative even when it is the object inside its own clause.

❌ Muž, který jsi viděl, je můj soused.

Incorrect — který is the object of viděl, so it must be the accusative kterého.

✅ Muž, kterého jsi viděl, je můj soused.

The man you saw is my neighbour.

2. Ignoring masculine animacy in the accusative. For an animate masculine antecedent, the accusative is kterého, not který.

❌ Pes, který jsme našli, byl vyhladovělý.

Incorrect — as the object of našli with an animate antecedent, it must be kterého.

✅ Pes, kterého jsme našli, byl vyhladovělý.

The dog we found was starving.

3. Wrong gender from the antecedent. The gender must match the noun referred to, even when the clause role is identical.

❌ Kniha, který leží na stole, je moje.

Incorrect — the antecedent kniha is feminine, so it must be která.

✅ Kniha, která leží na stole, je moje.

The book lying on the table is mine.

4. Dropping the pronoun the way English does. Czech cannot omit který.

❌ Film jsme viděli včera byl skvělý.

Incorrect — Czech needs an overt relative pronoun: film, který jsme viděli…

✅ Film, který jsme viděli včera, byl skvělý.

The film we saw yesterday was great.

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