LESSON NOTES · レッスンノート

N4Grammar, one piece at a time · Sep 14, 2026

こと vs の: two ways to turn a verb into a noun

こと and の both turn a verb or a whole clause into a noun. こと is abstract — facts, abilities, decisions. の is concrete — things you perceive directly. 子こどもが泳およぐ**の**を見みました is right; 泳およぐことを見みました is not.

Plenty of sentences accept either, which is why learners assume they are interchangeable and then produce the handful that are not.

The basics

The split

こと の
Feel Abstract, general Concrete, perceived
Typical verbs できる, ある, にする, になる 見みる, 聞きく, 待まつ, 手伝てつだう, 感かんじる
Register Slightly more formal, written Slightly more spoken

子こどもが泳およぐのを見みました。 — I watched the children swimming. (polite past — you saw it, so の) 日本にほんに住すんだことがあります。 — I have lived in Japan. (polite — an abstract fact, so こと)

The こと-only patterns

These four take こと and nothing else:

Pattern Meaning
〜ことができる can do
〜ことがある have done / sometimes happens
〜ことにする decide to
〜ことになる it is decided that

雨あめの日にちは歩あるいて行いくことがあります。 — On rainy days I sometimes walk. (polite — the "sometimes" use)

〜ことができる and 〜ことにする / ことになる are each their own grammar point; what matters here is that の cannot substitute in any of them.

The の-only patterns

Verbs of perception and of waiting or helping take の:

誰だれかが呼よんでいるのが聞きこえます。 — I can hear someone calling. (polite — heard directly) 彼かれが来くるのを待まっています。 — I'm waiting for him to come. (polite)

The rule underneath is that these verbs act on an event you experience, not on an idea. You cannot see a fact; you see something happening.

Beyond the basics

When either works

For subjects and topics, both are usually fine:

日本語にほんごを勉強べんきょうするのは楽たのしいです。 — Studying Japanese is fun. (polite — の, slightly more spoken)

日本語にほんごを勉強べんきょうすることは楽たのしいです is equally correct and sounds a shade more formal or written. In conversation, の wins.

好すき, 上手じょうず, 苦手にがて prefer の

料理りょうりをするのが好すきです。 — I like cooking. (polite)

料理りょうりをすることが好すきです is not wrong, but の is what people say. The same goes for 上手じょうず, 下手へた and 苦手にがて.

の becomes ん before です

This is where beginners have already met の without knowing it:

道みちが分わからないんです。 — The thing is, I don't know the way. (polite — の + です, contracted)

〜んです is the nominaliser の plus です, contracted in speech. Knowing that explains why んです frames things as explanations: it turns your sentence into a noun and then presents it as the situation.

こと as an ordinary noun

こと also just means "thing (abstract)" and appears everywhere:

大事だいじなことを忘わすれていました。 — I'd forgotten something important. (polite past)

そのことについて ("about that matter"), いいことがあった ("something good happened"), 私わたしのことが好すき ("likes me" — literally "likes the matter of me"). That last one is worth noticing: Japanese often says 私わたしのこと rather than 私わたし when talking about feelings toward a person.

こと at the end of a sentence

In written rules and instructions, こと functions as a command:

必かならず記入きにゅうすること。 — Be sure to fill this in. (written instruction — impersonal)

You will see this on forms and in workplace notices. It is not used in speech.

What does 〜ことで mean?

Verb + ことで is "by doing ~": the こと turns the action into a noun, and で marks it as the means. It answers "how?" with an action rather than a tool.

毎日まいにち書かくことで、漢字かんじを覚おぼえました。 — I learned kanji by writing them every day. (the method) 早はやく寝ねることで、朝あさが楽らくになった。 — Going to bed early made my mornings easier. (cause and result)

Only こと works here — 書かくので would change the meaning to "because I write." In speech, 〜して is often enough (毎日まいにち書かいて覚おぼえた), and ことで sounds a little more explanatory, which is why it is common in advice and presentations.

もの vs こと

もの is a physical thing, こと an abstract one:

甘あまいものが好すきです。 — I like sweet things. (polite — physical)

甘あまいことが好すきです would mean something bizarre. Where English says "thing" for both, Japanese splits them, and getting this wrong is more noticeable than getting こと/の wrong.

Common mistakes

  • 泳およぐことを見みました. Perception verbs take の: 泳およぐのを見みました.
  • 泳およぐのができます. できる takes こと: 泳およぐことができます (or just 泳およげます).
  • 待まつのを待まっています. The thing waited for takes の, and the pattern is 〜のを待まつ: 彼かれが来くるのを待まっています.
  • 甘あまいことが好すき. Physical things take もの.
  • Using こと in casual speech for everything. の is more natural in conversation.
  • Forgetting that んです is の. It explains why it sounds explanatory.

Practice

Answers are hidden — build yours first, then open. Questions 1 and 2 are a pair: same verb, and what the main verb does with it decides the nominaliser.

1. Say "I watched the children swimming."

Show answer

子こどもが泳およぐのを見みました — a perception verb, so の. You see an event, not a fact.

2. Say "I can swim."

Show answer

泳およぐことができます — できる takes こと and only こと. (泳およげます is the shorter everyday version.) This is the pair to question 1.

3. Say "I have lived in Japan."

Show answer

日本にほんに住すんだことがあります — an abstract fact about your history, so こと.

4. Say "I'm waiting for him to come."

Show answer

彼かれが来くるのを待まっています — 待まつ takes の. You wait for an event.

5. Say "I like cooking," the way people actually say it.

Show answer

料理りょうりをするのが好すきです — 好すき, 上手じょうず, 苦手にがて all prefer の. こと is not wrong, just stiffer.

6. What are the four patterns that take こと and nothing else?

Show answer

ことができる, ことがある, ことにする, ことになる — の cannot substitute in any of them.

7. What is んです made of?

Show answer

The nominaliser の plus です — which is why it frames things as explanations: it turns the sentence into a noun and presents it as the situation.

8. Something is wrong here: 甘あまいことが好すきです。

Show answer

甘あまいものが好すきです — もの is physical, こと abstract. English says "thing" for both.

9. Say "on rainy days I sometimes walk."

Show answer

雨あめの日にちは歩あるいて行いくことがあります — 〜ことがある also covers "sometimes happens," not only "have done."

10. What does 必かならず記入きにゅうすること mean, and where would you see it?

Show answer

"Be sure to fill this in" — on a form or a workplace notice — sentence-final こと is an impersonal written command. Not used in speech.

FAQ

Is こと written in kanji? 事こと exists but the grammatical use is normally kana. The ordinary noun sometimes takes the kanji.

Which should I default to in conversation? の. It is lighter and more spoken, and the こと-only patterns will announce themselves.

Can の be followed by は? Yes: 勉強べんきょうするのは楽たのしいです. の behaves as a full noun, so all the particles attach.

What about ところ? Different job — it nominalises a moment: 食たべているところです ("I'm in the middle of eating").

Is 〜ということ a separate thing? It means "the fact that," used to summarise a whole statement: 遅おくれるということです ("what it means is, they'll be late"). Common in business.

Why does 私わたしのことが好すき use こと? Japanese softens direct statements about people by referring to "the matter of" them. 私わたしが好すき is possible but blunter and can be ambiguous about who likes whom.

Vocabulary from this article

Tap the block to select all of it, then copy. In Anki: File → Import, note type Basic, separator Tab — the first column becomes the front, the second the back.

子ども	こども — child
泳ぐ	およぐ — to swim
見る	みる — to see, to watch
聞こえる	きこえる — to be audible
呼ぶ	よぶ — to call
待つ	まつ — to wait
住む	すむ — to live
日本	にほん — Japan
雨	あめ — rain
歩く	あるく — to walk
勉強	べんきょう — study
楽しい	たのしい — fun
料理	りょうり — cooking
好き	すき — to like
上手	じょうず — good at
苦手	にがて — bad at, not keen on
道	みち — road, way
分かる	わかる — to understand
大事	だいじ — important
忘れる	わすれる — to forget
甘い	あまい — sweet
記入	きにゅう — filling in (a form)
必ず	かならず — without fail
遅れる	おくれる — to be late

I'm Yuuki, a Japanese teacher based in Tokyo. I've taught on italki as a Top 1% teacher and watched over 1,500 anime. The moment worth waiting for in this lesson is when a learner realises んです has been の all along. A grammar point they had been treating as a mysterious politeness noise turns out to be something they already knew.

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Sources: the author's own lessons and standard reference grammars.

More drills like the ones above, plus a timed JLPT-style mock test: Practice · N4

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