I was reminded of this one again recently by an eikaiwa student I inherited from Jeff, and kind of just nodded along when it was explained since I've heard it used to many times before. I believe I've heard it before as an explanation for how Japanese people sometimes seem to be able to communicate so much to oneanother when so little is said, and thus why it can be difficult for an outsider to gain complete understanding. Being here for just 2 years has mostly refuted that idea in my mind, though I would say the phrase is still an apt for couples, close friends, and...well...the list goes on.
2. Communicating tacitly.
3. Understanding what somebody is thinking without prompting or words.
There are probably a hundred more ways for me to define this expression, but they're all tantamount to the same thing. It applies splendidly to all the moments where, without any prompting, you wonder aloud, "what was that one thing..." or "who was that one guy...", and your friend immediately gives the answer. CREEPY STUFF.
PS. I promise the next one won't be about ichiban group. For serious.