Can someone further explain the difference between 一緒に and 共に?


This is a follow up to the question “[What are the fundamental differences
between the ～と一緒に and the ～とともに
fragments?](https://japanese.stackexchange.com/questions/264/what-are-the-
fundamental-differences-between-
the-%EF%BD%9E%E3%81%A8%E4%B8%80%E7%B7%92%E3%81%AB-and-
the-%EF%BD%9E%E3%81%A8%E3%81%A8%E3%82%82%E3%81%AB-fragments)” Someone
suggested that I post my question as a separate thread.

Well, something is off for me. [It seems that
Derek](https://japanese.stackexchange.com/a/315/769) and [rcjsuen's
answer](https://japanese.stackexchange.com/a/310/769) clash somewhat. If I am
being explicit or am emphasizing who I am doing an activity with, this implies
that I and this person did everything together every step of the way. However,
according Derek's answer, I would use 一緒に. But according to rcjsuen's reply, I
would use 共に.

So what am I missing in this understanding?




Strange enough, in the case of the question thru your link
[here](https://japanese.stackexchange.com/questions/264/what-are-the-
fundamental-differences-between-
the-%EF%BD%9E%E3%81%A8%E4%B8%80%E7%B7%92%E3%81%AB-and-
the-%EF%BD%9E%E3%81%A8%E3%81%A8%E3%82%82%E3%81%AB-fragments), it seems that:

  * 「誰々と一緒に」is basically equal to 'with someone', but
  * 「誰々とともに」sounds a bit like 'someone followed me'.

In most of the cases they have zero differences. But sometimes we use
「誰々と共に」when we talk in a literary way, like「共に走ろう」.

