While studying I found this grammar form, which I kinda understand by instinct, but can't actually formalize in my head; this is what the book say:


1) 祖父は今日も孫のヒロシを話し相手にして散歩に出かけた。

2) 今回のキャンプを最後に、わたしたちのグループは解散することになった。

3) 卒業を1つの区切りとして、これからは自立して生きていきたい。

4) この大会に参加できるのは社会奉仕を目的とする団体だけです。

5) この研究会では環境問題を中心としたさまざまな問題を話し合いたいと思う。


I think I kinda get the general meaning:

1) 祖父は今日も孫のヒロシを話し相手にして散歩に出かけた。

Today Hiroshi's grandfather went out walking again with is grandchild Hiroshi as speaking partner [something like they speak while they walk, I guess?]

2) 今回のキャンプを最後に、わたしたちのグループは解散することになった。

It was decided that at the end of this camp our group would be dispersed

3) 卒業を1つの区切りとして、これからは自立して生きていきたい。

As one of the end of graduation, I want to be able to live indipendently from now on

4) この大会に参加できるのは社会奉仕を目的とする団体だけです。

Only associations working in the voluntary social services can attend this assembly

5) この研究会では環境問題を中心としたさまざまな問題を話し合いたいと思う。

In this seminar, whose focus are enviromental issues, I wat to discuss many issues

My problem is, I can't formalize this in my head, and my Japanese is failing me in clearly understanding the book's explanation ([~を~であると考えて] and 「N1をN2にして」という形で、ある行動や場面において、N1はN2であると言いたいときの表現); it seems to mean "N1 is N2", but then again I'm not sure about the sentences:


This seems to be 祖父はN1をN2として, whith N1 = 孫のヒロシ and N2 = 話し相手; so... the grandchild is the speaking partner? And the sentence means something like "As for the grandfather [祖父は], he went out to take a walk [散歩に出かけた] with his grandchild as speaking partner [孫のヒロシを話し相手にとして]"? Is in て-form because after the sentence continues, while とする would be used if the sentence ended?

If I were to asnwer to the question "Ok, but what does it mean?" I'd be confused explaining; it's kinds "N1 as N2", "N1 is N2", but I'm not sure that's all there is. The second sentence is proving particulary difficult to fit in this framework:

2) 今回のキャンプを最後に、わたしたちのグループは解散することになった。

N1 = 今回のキャンプ, N2 = 最後(に)? Or does N2 comprise something more? I can't fit it in "N1 is N2" frame no matter how I parse it.

I also found this question, which kinds seems to confirm my intuition, but it doesn't really help in formalizing it.

Edit: the book explains all the forms in the title with the same examples and explanation, hence this question's title; not sure about any difference among those forms.


1 Answer 1


Most of the time, you can think of the "AをBに(して)" construction as "with A as B", "with A at/in B", or "thinking/making/using A as B". This has been asked many times, so please take a look at these questions linked to this. AをBにする and AをBとする are usually interchangeable, but for the subtle difference, see とする・にする before a noun

  • 孫のヒロシを話し相手に
    = 孫のヒロシを話し相手にして
    = 孫のヒロシを話し相手として
    with his grandson Hiroshi as his chat partner (にとして must be a typo.)
  • 卒業を1つの区切りに
    = 卒業を1つの区切りにして
    = 卒業を1つの区切りとして
    with/making this graduation as a turning point (of my life)
  • 今日のキャンプを最後に
    = 今日のキャンプを最後にして
    = 今日のキャンプを最後として
    with/thinking/making this camp as the last one

These are adverbial (i.e., verb-modifying) expressions, but "AをB{と/に}{した/する}" forms attributive (i.e., noun-modifying) expressions as relative clauses.

  • 社会奉仕を目的に(して)
    with social services as the purpose
    → for the purpose of social services
  • 社会奉仕を目的{にする/にした/とする/とした}団体
    organizations for social services
  • 環境問題を中心に(して)
    with environmental problems as the core
    → focusing on environmental problems
  • 環境問題を中心{にする/にした/とする/とした}さまざまな問題
    various issues around environmental problems

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