I was talking to one of my friends about these particles (He is a native speaker of the language, and I thought he might know) and here's what he told me:

私は芋が彼を殺すと思います => I think the potato is killing him.

I asking him about why to write と instead of こと, and he couldn't explain it.

Ok, but why is it と? not こと? Every website that tries to explain it makes it seem like this would be correct. What am I missing?

(And yes, I know that phrase sounds stupid, but it was the only one that I could think of.)

  • 1
    The only phrase you could think of was someone being killed by a potato? Where do you live?
    – Earthliŋ
    Mar 22, 2015 at 16:44
  • 1
    I am the victim and the potato..... yes, I'm a potato, don't judge :)
    – Mavain
    Mar 22, 2015 at 17:27
  • Welcome to stackexchange! To help you understand these words better, could you add a short explanation what these websites are telling you about こと that would make it fit the sentence? I can't really think of what might be confusing about と vs. こと right now. Are you aware of the ~と思う construction?
    – blutorange
    Mar 22, 2015 at 18:00

1 Answer 1


I will preface this answer by saying there is no hard-and-fast rule, like with most particles, about when to use と and when to use こと. So, I'll try to stick directly to the context you provided.

The particle と is used in quite a few ways, but in this particular case (haha, get it?) it's a quoting particle.

It will rain tomorrow, too.

[Someone] said it will rain tomorrow, too.

It works a similar way for 思{おも}う. If something is a thought of yours, say, that "apples are tasty," the phrase 「りんごがおいしい」 becomes quoted.

I think apples are tasty.

The construct ~と思{おも}う is very common, and there's only a few circumstances in which you will see 思う without being preceded by a quoting particle (usually と).


However, こと is much different. It is not a quoting particle. It literally means "thing" (an abstract thing, not a physical thing). You might see it in a few contexts, generally following verbs.

Have you ever been to Japan? (lit. Have you ever done a thing where you went to Japan?)

I can swim! (lit. I can do swimming things!)

(There are many more situations you'd use it in, beyond these examples.)

So, why can't you use こと in your initial example?

x 私{わたし}は芋{いも}が彼{かれ}を殺{ころ}すこと思{おも}います。 (Wrong!)

This is ungrammatical and would awkwardly translate to English as something like, "I think potato to kill him." Over time, and as you get used to the usages of ~と思う, [verb]こと, and so on, you'll see which ones can be used in which situations.

Hopefully this sort of explains the difference.

Further reading

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