In the JLPTN5, 5th question, "弟は部屋◯掃除をしました"

I'm trying to understand why the の option is more appropriate than the に option. Both appear to be correct in English.

With に we are taking "the room" as indirect object (since に can be a substitution for the へ particle) and "cleaning" as a direct object; on the other hand, with the の option, we are taking "room's cleaning" as a direct object only. Am I forgetting something important here? Thanks for help.

3 Answers 3



The phrase 掃除する acts like a single verb. It's technically made of two words:

  1. the verbal noun 掃除
  2. the verb する

But together they act like a single verb. In this case, that verb is transitive, which means it takes a direct object marked by を:

部屋をobject 掃除するverb 'clean the room'

The verb is 掃除する, and its direct object is 部屋.


When you put を between 掃除 and する, they no longer act together like a single verb:

掃除をobject するverb 'do cleaning'

Now the verb is する by itself, and its direct object is the regular noun 掃除.

How do we add 部屋 to this clause? Well, the verb する already has one direct object, and we can't add another:

*部屋object 掃除object するverb ← ungrammatical

But we don't really want to relate 部屋 to する anyway. We want to relate it to 掃除, and that's a noun. How do we show a relationship between two nouns in Japanese? With the particle の:

[ 部屋の掃除 ]-を する 'do [the cleaning of the room]'

Now the verb is する 'do' and the direct object is the entire phrase 部屋の掃除 'the cleaning of the room'.


  1. Sometimes people explain 掃除する as ellipsis of 掃除をする. But it's important to realize that this is not the case:

    ​ 部屋掃除 する ← OK
    *部屋掃除する ← ungrammatical

    Adding を in like this makes it ungrammatical, so it can't be ellipsis.

  2. In this answer, I used English translations like 'do the cleaning'. In fact, you'd usually translate both 掃除する and 掃除をする to 'clean'. That's because when you translate, you look for the most natural way to express something in the target language. But in this case, my goal was to try to show the grammar of the original Japanese, so I deliberately used less natural sounding translations.

  3. In linguistics, phrases like 掃除する are called 'incorporated', while phrases like 掃除をする are called 'unincorporated'.

  4. The giant asterisk * is used in this answer to mark a sentence as ungrammatical.


It is because there is a を after 掃除.

If the verb of a sentence is a "suru verb", you can split apart the verb (掃除 in this case) and する. If you do, 掃除 will be interpreted as a noun and will be the direct object of the sentence's main verb する.

掃除する - To clean
掃除をする - To do cleaning

Are both valid phrases- but in the former, the entire thing is interpreted as one long verb, and in the latter the verb is only する and 掃除 is the direct object of suru. In other words, 掃除 is the thing you are doing.

Doing this, though, introduces a problem. If there is already a direct object in the original sentence, there will now be two を in the sentence. To avoid confusion, the original direct object (部屋 in your example) is marked with の instead.

部屋を掃除する - To clean the room
部屋の掃除をする - To do the room's cleaning

They are both essentially the same, but if you are interested in differences you can look at this question.

  • well that wasn't the goal of the question. but is a very good note and ill keep it in mind. thank you very much. indeed, as souji is a noun and suru verb you can use it, in both ways with the compromise of having a longer direct object. my question was about the inclusion of "room" as indirect object (where the cleaning was done?) you can use "de" as roughly to declare a location or "he" to declare the ind. object. ; as ni can replace de i think, always, then i thought i could "target the doing of the cleaning" where? to the room. (heya ni)
    – user66296
    Aug 2, 2015 at 20:45
  • You wouldn't say 部屋に掃除する, you'd say 部屋を掃除する. It's a direct object, not an indirect object.
    – Blavius
    Aug 2, 2015 at 21:14
  • 1
    "ni can replace de i think, always" >> No, you'd say 部屋入る not 部屋入る, and 部屋勉強する not 部屋勉強する.
    – chocolate
    Aug 3, 2015 at 2:42


With の it is saying the younger brother did the cleaning of the room. This clearly states with no uncertain terms that he cleaned the room.


The latter isn't as clear cut from what I can tell.

I originally thought that it would end up meaning that he was cleaning something in the room, but as Earthliŋ said, since cleaning is an activity, the correct particle for saying that he was cleaning something in the room would be で: 「弟は部屋で何かの掃除をしました。」.

  • 2
    に doesn't work, since he's cleaning (which is an "activity"), so it should be 部屋掃除をしました.
    – Earthliŋ
    Aug 2, 2015 at 14:21
  • Revised based on your comment.
    – Pandacoder
    Aug 2, 2015 at 14:38
  • appears to be the correct answer as sugested by @Pandacoder. that's not even a japanese question that's my bad. when we say "to do cleaning" we are talking about a completing a task; so my question "acting over a task (thru direct) and then deliver it to the room (thru indirect)" makes no sense. so the correct answer would be to specify which task it is with the "no" particle, that is, room's cleaning. thanks
    – user66296
    Aug 3, 2015 at 0:22

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .