Again, I am not referring to the intransitive usage of 完成する.




From my understanding of the grammar, させる implies that you could be making other people help you along as well, but I'm not sure, it seems like in the example sentences there shouldn't be much nuance differences.


2 Answers 2


Most Sino-Japanese words could originally be used both transitively and intransitively, some even as all verb, noun and adjective, as they are in Classical Chinese. But since they have been more and more Japanized, many of them were assigned a fixed grammatical status like other native words.

完成 is almost exclusively intransitive nowadays. Dictionaries may say it's also transitive, but that usage has nearly died out in actual world (though not incomprehensible). Thus, if you'd like to use 完成 transitively, you should choose 完成させる.

実現 still retains the ambiguity, so unfortunately you're not able to know if a 実現する is "to realize" or "to be realized" without help of context. In your case, 夢を実現する is not ambiguous (because it takes を), but 夢を実現させる allows two interpretations: "realize one's dream" or "make one realize one's dream".

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    It's unfortunate that this type of information isn't really available in any free online dictionaries (e.g., kotobank.jp/word/%E5%AE%8C%E6%88%90-470378 doesn't really say much -- no particular mention of transitivity, and there's only a single transitive usage example and it's を完成する). Aug 18, 2015 at 19:23
  • @DariusJahandarie True. I tried to search for it before answering but I only found those information is surprisingly scarce. Mainstream dictionaries (well, maybe they have to cover usages up to Meiji...) aren't much of help, but I wonder how 三省堂 or some more contemporary-oriented ones treat them. This book seems to be hopeful, but someone is borrowing it through the vacation from our library. Aug 19, 2015 at 3:28
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    (For those not following the chat room...) it turns out that 明鏡国語辞典 does list transitivity for する verbs; and not only does it list that both are possible, it lists the the exact usage (i.e., that while both are possible it's usually 完成させる that's used for the transitive). Nice iPhone app available to boot -- if only it were freely available :-). Aug 21, 2015 at 22:59
  • @Daius Just to understand your comment - So according to that dictionary, the guideline is that 完成する is intransitive and 完成させる is transitive. Is that correct? So it would be 文を完成させる and 文が完成する.
    – kandyman
    Dec 6, 2018 at 0:16
  • @kandyman Yes (and your mention won't reach him I guess...). Dec 6, 2018 at 1:47

It depends on whether させる is causative or transitive that it means that you make other people do it. Both させる and する can imply that you involve other people.

When させる is transitive (not causative), they (する and させる) are the same. But the させる version is more common, especially 完成させる is much more common. If I were to find 文を完成しなさい on Lang-8, I would correct it to 完成させなさい.

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    Here in this pdf, on the site related to handbook "Tobira", it says 文を完成しなさい tobiraweb.9640.jp/wp-content/uploads/L15_grammar_exercise.pdf ...while in the actual handbook they use 文を完成させなさい My japanese teacher thaught me the same... still, after reading some dictionaries, I get the feeling this is a rather controversial point. Nov 29, 2015 at 21:55
  • But isn't させる always causative? It's the causative form (使役形), after all. Can a verb be conjugated in the causative form and not be causative?
    – kandyman
    Dec 4, 2018 at 11:52

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