I must admit I was a little surprised at how much of a mad-house it was because I've flown in Japan at that time of the year quite a bit before and it was never that bad. There was just a lot of planes leaving at that time (late morning) and it seemed all the check-ins counters being used were in the same area. Result- total chaos. An hour later it was calm again. Japanese airports generally get high marks from me right down the line. As Jpatokal said, domestic is a breeze. I've arrived at check-in 20 minutes before my flight once and they didn't even bat an eye-lid. I love Kansai just lucked out last time I guess.