English blurs který and jaký into the single fuzzy pair "what / which", and learners pick whichever feels right — often wrongly. Czech keeps them sharply apart, and the line between them is clean once you see it. Který picks one item out of a known set ("which one?"). Jaký asks about quality, type, or character ("what kind of?", "what … like?"). Choose by what you're really asking, not by the English word.
The core distinction
| Word | Asks | Expects as an answer |
|---|---|---|
| který | which one (of a definite set)? | a specific item: "ten červený", "tamten" |
| jaký | what kind / what … like? | a quality or type: "dobrý", "rychlé", "modré" |
Který assumes a closed, known set and asks you to single one out — which bus of the several at the stop, which book off the shelf, which day of the week. The answer is a pick.
Který autobus jede do centra?
Which bus goes to the centre? (of the buses here — pick one)
Kterou knihu si chceš půjčit?
Which book do you want to borrow? (from these on the shelf)
Ve kterém patře bydlíš?
Which floor do you live on?
Jaký asks what something is like — its quality, type, or characteristic. The answer is a description, an adjective, a kind.
Jaký je ten nový film? Stojí za to?
What's the new film like? Is it worth it?
Jaké máš auto?
What (kind of) car do you have?
Jaká byla cesta? Nebyla moc dlouhá?
How was the journey? Wasn't it too long?
The test
Hold the sentence up to one question:
- Am I choosing from specific options I could point at? → který ("which one").
- Am I asking what something is like / what type it is? → jaký ("what kind").
The cleanest proof is the answer you expect. If the natural reply is "this one / the red one / number 12" — a pick — you wanted který. If it's "good / fast / blue / boring" — a description — you wanted jaký.
Jaké víno máš radši, bílé, nebo červené?
What kind of wine do you prefer, white or red? (a type)
Které víno si dnes dáme k večeři?
Which wine shall we have with dinner tonight? (pick one bottle)
Both decline like adjectives
Který and jaký are not frozen little words — they are full adjectives in disguise, declining like the hard pattern mladý and agreeing in gender, number, and case with the noun they modify. That agreement is non-negotiable: a feminine accusative noun pulls kterou / jakou, a masculine animate accusative pulls kterého / jakého.
| Gender / case | který | jaký |
|---|---|---|
| masc. (nom.) | který | jaký |
| fem. (nom.) | která | jaká |
| neut. (nom.) | které | jaké |
| fem. (acc.) | kterou | jakou |
| masc. anim. (acc.) | kterého | jakého |
S kterým kolegou jsi mluvil?
Which colleague did you speak with? (instrumental after s)
Na jaké škole studuješ?
What kind of school do you study at? (locative after na)
jaký in exclamations: "What a …!"
Beyond questions, jaký carries the exclamation "what a …!" — admiring or lamenting a quality. It still agrees with its noun, and it usually sits before an adjective + noun. (Here který is impossible; you are exclaiming about a quality, not selecting.)
Jaký krásný den! Pojďme ven.
What a beautiful day! Let's go out.
Jaká škoda, že nemůžeš přijít!
What a pity you can't come!
Jaké překvapení, že tě tu potkávám!
What a surprise to run into you here!
Why English speakers get this wrong
English gives you no reliable signal. "Which" usually points to který and "what kind of" usually points to jaký, but everyday English happily says "What bus goes downtown?" (meaning which line) and "Which wine do you like?" (meaning what kind). The English word, in other words, lies to you. Worse, English can drop the question word entirely — "Got a car?" / "Nice car — fast?" — where Czech still has to commit to jaký. The fix is to ignore the English surface and ask yourself the underlying question: am I narrowing a set, or describing a quality? Narrowing a set is always který; describing a quality is always jaký. Anchor on that and the slippery English no longer drags you to the wrong word.
A note on co and "what kind of"
Two related traps. First, don't confuse jaký with co ("what" as a bare thing): Co to je? asks the identity of an object ("What is it?"), while Jaké to je? asks its quality ("What's it like?"). Second, in casual speech you'll hear co je to za + accusative as a colloquial stand-in for jaký — Co je to za auto? ("What kind of car is that?"). It's perfectly idiomatic but informal; jaký is the neutral, all-purpose choice.
Common Mistakes
❌ Jaký autobus jede do centra? (meaning: which line)
Wrong word for picking a line — singling one out of the buses here is který.
✅ Který autobus jede do centra?
Which bus goes to the centre?
❌ Který je ten film? (meaning: what's it like)
Wrong word for quality — asking what something is like is jaký.
✅ Jaký je ten film?
What's the film like?
❌ Jaká kniha chceš?
Two errors — for picking a specific book use který, and the accusative object needs kterou.
✅ Kterou knihu chceš?
Which book do you want?
❌ Který knihu si vezmeš?
Agreement error — the feminine accusative noun knihu requires kterou, not který.
✅ Kterou knihu si vezmeš?
Which book will you take?
Key Takeaways
- který = "which one" — singles an item out of a known, definite set; expect a pick as the answer (Který autobus? Kterou knihu?).
- jaký = "what kind / what … like" — asks about quality, type, or character; expect a description (Jaký je ten film? Jaké máš auto?).
- The test: choosing among options ⇒ který; asking what something is like ⇒ jaký.
- Both decline like the adjective mladý and agree with their noun — mind the case (kterou knihu, na jaké škole).
- jaký also makes exclamations: Jaký krásný den! ("What a beautiful day!").
Now practice Czech
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Start learning Czech→Related Topics
- jaký vs který: What Kind vs Which OneB1 — Both translate as 'what' or 'which', but jaký asks about quality or kind while který asks you to pick one out of a known set.
- který: The Main Relative PronounB1 — který/která/které declined as a hard adjective, the workhorse relative 'which/that/who'.
- kdo and co: Who and WhatA2 — The pronouns kdo (who) and co (what) as both question words and relatives, with their full declension and their fixed singular agreement.
- Question Words and Their CasesA1 — The full set of Czech question words — and the crucial fact that kdo and co decline, so the question word must take the case the verb or preposition demands.
- Common Mistakes: ten versus kterýB1 — Confusing the demonstrative ten with the relative pronoun který.