• Particle
    か indicates that something is unknown. It's used to form questions, indefinite pronouns, and lists of alternatives.

    Table of Contents

    The Basics

    We often think of particle か as "the Japanese question mark," but it's actually a marker of the unknown. It can be used to mark a sentence as a question, or to express alternatives, like "either … or …" in English. We can also add か to a question word to form an indefinite pronoun, as in 誰 (who) + か = 誰か (someone). If you keep in mind that か marks the unknown, then you can see how these different uses are all related!

    picture of ka

    か for Asking Questions

    It's very simple to form a question sentence in Japanese. Simply adding か to the end of a sentence does the trick.


    • 今日は暑いです。
    • It is hot out today.


    • 今日は暑いです + か。
    • Is it hot out today?

    That's all it takes! In English, we have to switch the word order to form a question — notice how "it" and "is" switch places in the translation? In Japanese, there is no such requirement. Just add か! You may have also noticed that the Japanese question has the same punctuation as the statement. Traditionally, written questions in Japanese still end in "。" since the か particle is enough to signal that the sentence is a question. Nowadays though, you'll see "?" replace "。" in a lot of informal writing.

    か for Alternatives

    The next use of か we'll look at is how they mark two or more elements as alternatives. This is kind of like using "either … or …" in English.

    • 誕生日は [お母さん] [お父さん] がケーキを作ってくれる。
    • On my birthday, either my mom or my dad will make me a cake.

    If you keep in mind that か is not a question marker, but a marker of the unknown, this use makes a lot of sense, right? In the example sentence, it's unknown whether it's your mom or your dad who will make the cake.

    If a particle like が or を follows a list of alternatives, you'll usually drop either that particle or particle か. In the example above, the alternatives listed (my mom or my dad) are the subject of the sentence, so they are marked with particle が. Our sentence will be most natural if we drop one of these, か or が:

    • 誕生日はお母さんかお父さん (か / が) ケーキを作ってくれる。
    • On my birthday, either my mom or my dad will make me a cake.

    This also applies if the alternatives are the object of the sentence, in which case they're typically marked with particle を. Again, it's most natural to choose one:

    • 今日はカレーかパスタ (か / を) 作ると思う。
    • I think I'll make either curry or pasta today.

    か for Indefinite Pronouns

    This next use of か also draws on its role as a marker of the unknown. If you add か to the end of a question word, it transforms it into an indefinite pronoun. An indefinite pronoun is a word that replaces a noun, and leaves the identity of that noun unknown. In English, these are words like "something," "someone," and "somewhere."

    誰 + か = 誰か
    who  (ka)  someone

    何 + か = 何か
    what (ka)  something

    いつ + か = いつか
    when  (ka)  sometime

    どこ + か = どこか
    where  (ka)  somewhere

    Indefinite pronouns can be used anywhere that a typical noun could be, such as the subject or object of a sentence.


    • 誰かがいると思う。
    • I think someone is here.


    • 誕生日だから、何か買ってあげようよ。
    • It's their birthday, so let's buy something for them.

    Beyond the Basics

    Intonation of か in Questions

    Remember how we said か isn't a question marker, but a marker of the unknown? Well we're really gonna dive into that idea in this section! The nuance that か adds to a sentence often hinges on whether it's pronounced with rising or falling intonation. Let's check it out.

    • 何時に食べに行きますか?
    • What time shall we go out to eat?

    This sentence is in the polite form, marked by the 〜ます ending on the verb, 食べます. When a question is asked in the polite form, adding か to the end is pretty standard. When か is added to a question in the plain form however, it can sound very direct, especially if pronounced with rising intonation. This isn't a particularly common way to ask questions, but is found in masculine Japanese.

    • もう行ったか?
    • Did you already go?

    If か is pronounced with falling intonation though, it changes the meaning from an actual question, to an acknowledgment of new information, or a realization.

    • もう行ったか。
    • Oh, they already went.

    This か is still considered a marker of "not knowing," in that you are indicating you didn't know the information up until that moment. You might say もう行ったか to yourself when you realize you've been left behind. These self-directed, rhetorical questions are common in Japanese, and are pronounced with falling intonation:

    • そうか。
    • Is that so.

    そうか is a pretty ubiquitous example of how intonation is more important than か in questions. While falling intonation makes it a statement, like "is that so" or "I see," the meaning changes with rising intonation:

    • そうか?
    • Is that so? 🤔

    Pronounced with rising intonation, そうか suggests that you are questioning what someone just said to you. Depending on the context, you might actually not believe they're correct about what they said, or you might just be challenging them in jest. Be careful though, this use of そうか could come across quite strong or rude with someone you aren't close to.

    In summary, it is rising intonation, not particle か, that indicates a question in spoken Japanese. For this reason, you can ask a question with nothing more than rising intonation, both in the plain and the polite form.

    • 何時に食べに行きます?
    • What time shall we go out to eat?
    • そろそろ行く?
    • Is it about time we go?

    か in Embedded Clauses

    An embedded clause is kind of like a sentence within a sentence. If the clause you want to embed is expressing something unknown, you can use か to embed - in other words, insert - that clause into another sentence. The clause you insert might be an "embedded question," or "embedded alternatives." We'll start off by looking at embedded questions.

    Embedded Questions

    • キャメロンがウェイターに [グラスワインはいくら] と聞きました。
    • Cameron asked the waiter how much a glass of wine is.

    In this example, we see that the question グラスワインはいくらか is embedded inside the larger sentence キャメロンがウェイターに[〜]と聞きました. Particle と, which is used to make both direct and indirect quotations, appears immediately after the embedded question. Since both か and と indicate the end of the embedded clause, we don't necessarily need to keep both in the sentence. One option is to drop particle と:

    • キャメロンがウェイターに [グラスワインはいくら] _聞きました。
    • Cameron asked the waiter how much a glass of wine is.

    In the previous section, we talked about how a question in the plain form usually does not take か, because it can sound overly direct, and potentially rude. In an indirect quotation though, this effect is not present. か in an embedded question just helps to clarify that the embedded clause is in fact a question, without adding any nuance.

    However, since the embedded clause in this case contains the question word いくら (how much) and the main verb of the larger sentence is 聞きます (ask), it's pretty clear even without か that the embedded clause is a question. For this reason, we can also choose to drop か and leave と in the sentence instead:

    • キャメロンがウェイターに [グラスワインはいくら_] と聞きました。
    • Cameron asked the waiter, "how much is a glass of wine?"

    Without か, this sentence sounds a bit more like a direct quote (notice the quotation marks in the English translation). This is because asking questions in the plain form without か (and using rising intonation) is a common way to ask questions, so this could be a direct quote of the way Cameron asked the waiter his question. Particle と reinforces this, since it is a marker of quotation. The resulting nuance is that Cameron sounds a bit overly casual with the waiter. Typically, it is more appropriate to ask questions to people you don't know in the polite form, so グラスワインはいくらですか would be more appropriate.

    Embedded Alternatives

    In addition to embedding a question clause, you can also embed clauses into a sentence as alternatives. In this case, か works similarly to "whether … or …" in English. Since we're no longer quoting anyone, we won't use particle と this time.

    • 今日は [赤ワインにする] [白ワインにする] まだ決まってない。
    • I haven't decided whether I'll have red wine or I'll have white wine today.

    You can also embed only one clause with か to express something like "if" in English:

    • 今日は [まみさんも来る] 知ってる?
    • Do you know if Mami is coming today?

    In this case, you can optionally add in どうか as well to mean something equivalent to "or not" in English:

    • 今年はまみさんも来るかどうか知ってる?
    • Do you know if Mami is coming or not today?