If you ever see an idol concert, don’t only pay attention to the performers – if you do, you’ll be missing out on what is perhaps the most unique aspect of Japanese concerts. That is wotagei.
It seems that wota, or people who are devoted fans of a particular idol group, coordinate very advanced dances for particular songs, using glowsticks, and then perform them in the audience while the performers are dancing on stage. Let me repeat this: there is an entirely different performance, synced to the stage performers, happening in the audience.
These performances are called wotagei. And some of them are particularly complex, using vocalizations, etc.
I am not aware of this phenomenon occurring, ever, in western concerts. In fact, in western concerts, there is an area near the stage called a “mosh pit” which, near as I can tell, seems to be a place where people just do whatever the heck they want. As near as I can tell (and I’ll stand corrected if I’m wrong, because the only concerts I’ve ever been to involved sitting quietly while the conductor waves his or her arms).
Still, this is a fascinating thing. I am sure there is a cultural reason for this, probably involving ritual, conformity, and community, but I can’t pretend to truly understand it. Still, it is a very interesting thing that, once you know to look for it, adds an entirely new dimension to watching J-pop concerts.