I'm accustomed to saying together with using the ~ to issho ni fragment, but I've been noticing that some people I talk to phrase this using ~ totomo ni instead.


Kanojo to issho ni Nihon e kita.


Kanojo totomo ni Nihon e kita.

seem to be fundamentally equivalent.

Are there any nuances that the two have that dictates when and where they should be used? Probably very slight meaning deviations? Or are they essentially perfect equivalents of each other when it comes to saying together with (and yeah, I'm aware that ~ totomo ni has other meanings aside from that)?

4 Answers 4


一緒に, as you say, is regularly used for saying doing something "together". 共に(ともに) is more explicit about who you are performing this action with, thereby placing a stronger emphasis on the bond/camaraderie.


Fight together with me!


Fight hand-in-hand/side-by-side with me!

So I would say you'd pick which to use depending on whether you are trying to place an emphasis on the action or the other person(s) involved.

  • Exactly the kind of answer I was looking for! +1 Commented Jun 1, 2011 at 12:54
  • 2
    "Fight together with me!" and "Fight hand-in-hand/side-by-side with me!" are imperative, right? 私と一緒に戦います!/私と共に戦います! are not imperative. When I heard 私と一緒に(or共に)戦います!, I'd want to ask "え?誰が?"
    – user1016
    Commented Dec 29, 2012 at 16:08

According to page 91 of the 類義語使い分け辞典 [1], quoted here, 一緒に requires that the action take place in the same time and location. 共に does not have this restriction, so the subjects may perform the action (let's say 日本へ行く) at the same time but via a different route, or via the same route but at slightly different times. 「彼女と一緒に日本へ来た」 means that you and she came to Japan at the same time and were together the entire way, but 「彼女とともに日本へきた」 could mean that you came to Japan at the same time, but took different flights to get there.

To provide another example (extracted from Google), consider 「一緒に学ぼう!共にがんばろう!」. The first sentence shows that the action, 学ぶ, is being done at the same time and in the same location. The second sentence uses 共に instead of 一緒に, and so the best interpretation is probably that the action, がんばる, is being done by everyone at the same time, but in their respective locations.


  1. 類義語使い分け辞典 (Google Books)
  • Very well-rounded, exhaustive answer. Thanks a lot! Commented Jun 1, 2011 at 13:26
  • I have this book (along with the related grammar book) and they're freakin' awesome! Definitely worthwhile if you're into reading dictionaries for fun.
    – istrasci
    Commented Jun 1, 2011 at 14:13

No, they are not equal in meaning. "一緒に", as already stated by some people, is used more in casual situations. I can't imagine people saying "共に" in usual conversations but I can easily imagine a politician saying "共に". However, I wouldn't call "一緒に" an informal word or "共に a formal word. I would say "共に" sounds more solemn than formal.

Now, the question is where is the boundary to decide when to use which one, "一緒に" or "共に"?

  • a.)一緒にがんばろう [To your friend(s) or family member(s)]
  • b.)一緒にがんばりましょう [To your colleague(s) or people in business relationship. You can say this to someone you've just met if needed.]
  • c.)共にがんばろう [To your subordinates/students. Even though "がんばろう" is not a formal form, it would still sound weird in casual conversations among friends/family members]
  • d.)共にがんばりましょう [nearly the same as b.) probably because the situations where "共に" is allowed are overlapped by the ones where "がんばりましょう" is allowed.]

"共に" sounds more solemn than "一緒に", by which I mean, "共に" places more importance on the task that will be done together. "共に" makes you feel like you are part of "something big" giving the speaker more power. This explains why it can't be used in casual conversations. "共に" gives the hearer more impression and emphasizes the importance of the task.

You should use "一緒に" in usual conversations if you are not making a public speech or talking to a business partner. Literature prefers ”共に" because of its solemnity. Your example, 彼女とともに日本へきた。sounds like a sentence right out of a novel or a character's monologue.

Also, "共に" tends to be used in advertising or invitation, in order to show how serious we are about what we are going to do together.


It could be the case that とともに is more formal version of 一緒

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