I know they have the same meaning but what are the small details? I remember seeing the structure お+verb stem+する used in humble speech, but here the お is omitted.

  • Does this answer your question?
    – jarmanso7
    Oct 23, 2022 at 23:46
  • 1
    I don't think it's related to the humble/honorific forms of Japanese. There's some pairs of verbs that for historical reasons have both forms す and する, such as 引っ越す/引越しする, 適す/適する, etc. IIRC there was a Q&A specifically about this but I couldn't find it, I've linked above a related answer.
    – jarmanso7
    Oct 23, 2022 at 23:49
  • @jarmanso7 Is this possibly the Q&A you are referring to? I think this Q&A answers op's question about the difference between 引っ越す and 引っ越しする
    – konsty
    Oct 24, 2022 at 1:13
  • If this is asking about such pairs as 適す/適する, then 引っ越しする is not a good example because 引っ越し is a noun and you can say 引っ越しをする, too. If it is asking specifically about 引っ越す/引っ越しする, it is a duplicate.
    – aguijonazo
    Oct 24, 2022 at 2:10
  • @aguijonazo fair point, if I am not mistaken, the inflections that 引っ越す can take mirror those of such verbs as 適す and that's why I tend to group them
    – jarmanso7
    Oct 24, 2022 at 7:57

1 Answer 1


You are confusing a noun for a verb.

  • 引っ越す - verb in dictionary form
  • 引っ越します - verb in masu form + ます
  • 引越しします - noun which derived from masu-form + し(する in masu-form) + ます

In school grammar, this is called 連用形の名詞化 (nominalization of te/masu-form). 引っ越し is certainly a masu-form, but it can also be a noun on its own. (BTW 引っ越し can't be called a stem; its negative form is 引っ越さない.)

The complication is that not all verbs can be turned into nouns in this way, and you must look up dictionaries whether or not it is an accepted nominal form.

For example, the equivalent to above of 起きる is 起き, but this by itself is not a noun and ×起きします is not acceptable. On the other hand, 早起き is a totally common word and 早起きします means (I) wake up early.

This contains a bit more details.

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