Wow. That's pretty bad and I haven't seen it that bad before- I often fly into Narita on Saturday afternoons around 3pm and it's generally pretty light (terminal 1). The madness I have seen is when flying out on Sunday afternoon... typically outbound immigration gets a bit crazy after 4 o'clock. I'm curious if the OP meant you flew in on Saturday or Sunday.. could you clarify? Also, you are flying that much and not using the automated gates?