How to use the nominalizers の [no] and こと [koto] in Japanese?

In Japanese, you can use の[no] and こと[koto] to turn and into . In grammar, we call words like these nominalizers. You’ll most often use them when an action is the or of a sentence, as in “Running is fun.” or “I practiced running.”

To turn a word into a noun in Japanese, you’ll add の[no] or こと[koto] to the plain form of a verb or adjective.

But these two nominalizers aren’t completely interchangeable! When do you use の[no] and when do you use こと[koto]? When and how should you use a nominalized verb in a Japanese sentence? Those are all topics we’ll cover in this post! Read on and find out how to use these nominalizers correctly and effectively!

When the nominalized action is happening at the same time as the main action in a , you must use の[no]. A bit abstract? Let’s look at some cases where you might need to use this nominalizer.

• Perception

  When you see or hear something happening, it must be happening at the same time as you’re seeing it, so you’ll need to attach の[no] to the action you’re seeing.

  perceived actionnominalizerverb of perception

  鳥が飛ぶのを見ました。

  Tori ga tobu no o mimashita.

  I saw a bird flying.

  母が歌うのが聞こえます。

  Haha ga utau no ga kikoemasu.

  I hear my mother singing.

  Here is a list of verbs of perception that commonly trigger this structure:

  Verbs of Perception
  Japanese	English
  見る[miru]	to see
  見える[mieru]	to be visible
  聞く[kiku]	to hear
  聞こえる[kikoeru]	to be audible
  感じる[kanjiru]	to feel

• Acting on another action

  Use の[no] with the verbs that indicate how someone is interacts with another action.

  other actionnominalizermain verb

  友達の授業が終わるのを待ちます。

  Tomodachi no jugyō ga owaru no o machimasu.

  I wait for the end of my friend’s class.

  母がカレーを作るのを手伝います。

  Haha ga karē o tsukuru no o tetsudaimasu.

  I help my mother with making curry.

  ねこは私が勉強するのをじゃましました。

  Neko wa watashi ga benkyōsuru no o jama shimashita.

  My cat interfered with my studying.

  走るのを止めました。

  Hashiru no o yamemashita.

  I stopped running.

• Emphasis on a nominalized action

  の[no] is also used when the nominalized verb is emphasized.

  emphasized nominal verbnominalizer

  遊びに行くのはだめですよ！

  Asobi ni iku no wa dame desuyo!

  You can’t go to play!

  lit. Going to play isn’t good!

When the action in the nominalized verb is not happening at the same time as the action in the , you’ll need to use こと[koto] to nominalize the verb. As we saw above, you just need to add it to the plain form of the verb (present or past).

Here are some cases when you’ll need to use こと[koto] as the nominalizer:

• Thinking and speaking

  Use こと[koto] when actively talking or thinking about an action.

  action discussednominalizermain verb

  先生に宿題を忘れたことを言いました。

  Sensei ni shukudai o wasureta koto o iimashita.

  I told (my) teacher about (my) forgetting homework.

  留学することについて、先生と話しました。

  Ryūgaku suru koto nitsuite sensei to hanashimashita.

  I spoke with my teacher about (my) studying abroad.

  日本に行くことを考えました。

  Nihon ni iku koto o kangaemashita.

  I thought about going to Japan.

  友達が日本にいることを思いました。

  Tomodachi ga nihon ni iru koto o omoimashita.

  I thought about my friend being in Japan.

• The nominalized verb is a “state of being”

  We use こと[koto] when the nominalized action describes the subject’s general situation. In English, these are actions that follow the verb “to be,” but in Japanese the nominalized verb will be followed by an ending like 〜だ[da] or 〜です[desu].

  actionnominalizer"to be" ending

  私の仕事は本を書くことです。

  Watashi no shigoto wa hon o kaku koto desu.

  My job is writing books.

  Check out our post on the state-of-being in Japanese to learn more about how to build “to be” sentences like this!

In some situations, you can use either の[no] or こと[koto] with a verb plain form. The meaning doesn’t change much, but の[no] is more casual and colloquial to use, while こと[koto] elevates the formality ever so slightly. Let’s look at the situations where both nominalizers are possible!

• Opinions or feelings about an action in general

  If expressing your general opinions or feelings about an action, you can use either の[no] or こと[koto] to nominalize the action.

  actionnominalizerfeeling expression

  ビデオゲームを［するの・すること］は楽しいです！

  Bideo gēmu o [suru no / suru koto] wa tanoshii desu!

  Playing video games is fun!

  私は歌を［歌うの・歌うこと］が楽しいです。

  Watashi wa uta o [utau no / utau koto] ga suki desu.

  I like singing.

  → 好き[suki] is technically an adjective meaning “liked.”

  私は歌を［歌うの・歌うこと］が楽しいです。

  Watashi wa uta o [utau no / utau koto] ga suki desu.

  I like singing.

  私は病院に［行くの・行くこと］が嫌いです。

  Watashi wa byōin ni [utau no / suru koto] ga kirai desu.

  I hate going to the hospital.

  → 嫌い[kirai] is technically an adjective meaning “hated.”

• Mental reactions to an action:

  Verbs expressing mental reactions to an action can be used with actions nominalized by either の[no] or こと[koto].

  actionnominalizermental reaction

  私は彼が［成功するの・成功すること］を信じる。

  Watashi wa kare ga [seikō suru no / seikō suru koto] o shinjiru.

  I believe in his succeeding.

  私の家族は私が［勉強しすぎるの・勉強しすぎること］を心配している。

  Watashi no kazoku wa watashi ga [benkyō shisugiru no / benkyō shisugiru koto] o shinpai shiteiru.

  My family is worried about my studying too much.

  母にプレゼントを［買うの・買うこと］を忘れました。

  Haha ni purezento o [kau no / kau koto] o wasuremashita.

  I forgot to buy my mother a present.

  Note that these are mostly reactive or involuntary verbs of thinking, which makes them different from verbs for actively recollecting or considering an action, which always take actions nominalized by こと[koto].

• When nominalizing adjectives:

  In most cases, you can use either nominalizer when nominalizing adjectives. For example, you may want to say that you were surprised at the “expensiveness” of a car. You can say:

  adjectivenominalizer

  車が高いのにおどろきました。

  Kuruma ga takai no ni odoroki mashita.

  I was surprised at the expensiveness of a car.

  車が高いことにおどろきました。

  Kuruma ga takai koto ni odoroki mashita.

  I was surprised at the expensiveness of a car.

  Just as you did with the verbs, take the plain form of an adjective and add の[no] or こと[koto].

  ⤷ TIP

  There are other ways to nominalize an adjective as well, like using 〜さ[sa] or 〜み[mi]. Check out our post on changing the part of speech of adjectives to learn more!

• When nominalizing clauses:

  In most cases, you can use either の[no] or こと[koto] to nominalize a clause. We’ll discuss this more in the next section!

You can also use の[no], or sometimes こと[koto], after a complete to create a phrase approximately meaning “the fact that” + clause. For example:

In Japanese, you’ll most often use phrases like this as the object of a verb that takes a fact as its object, like 知る[shiru](to know) or わかる[wakaru](to understand), or even some verbs of speech like 説明する[setsume isuru](to explain).

What makes these tricky, though, is that in order to attach の[no] or こと[koto] to a clause, you first need to turn that clause into an adjective. In other words, you can only attach の[no] and こと[koto] to a .

In this context, you can almost always use either の[no] or こと[koto] after a relative clause.

Nominalized words must be treated as nouns in a Japanese sentence, which means that they’ll be marked by the same sorts of particles that usually mark nouns. Just add the particle after the nominalizer.

In this post, we’ve covered how to use の[no] and こと[koto] to nominalize words and phrases in Japanese, and when to use each one. Remember these points:

• ONLY use の[no] for:

  • the objects of verbs of perception (e.g. seeing, hearing,...)

  • an action being affected by another action (e.g. helping, interfering, waiting,...)

  • an emphasized nominalized verb

• ONLY use こと[koto] for:

  • objects of intentional thought and speech (e.g. telling, thinking,...)

  • when the nominalized verb is used as the predicate of a state-of-being sentence (e.g. is writing,..)

• の[no] and こと[koto] can both be used for:

  • an action someone has general opinions or feelings about

  • the object of verbs for mental reactions to an action (e.g. worrying, forgetting,...)

  • nominalizing adjectives

  • nominalizing clauses (with some exceptions)

Now, are you ready to practice what you’ve learned? Check out our の[no] and こと[koto] exercises! Happy learning!