I am thinking of booking YYZ-PVG-NRT. YYZ-PVG is on AC, and PVG-NRT is on NH, all on one ticket. There is a 3 hour gap between flights. Does the transfer require clearing immigration and going land side? I have no checked luggage. I've read conflicting reports in which some state you do, some say you don't. Also read that many flights into and out of PVG are usually delayed in which I am wondering if the 3 hour connection time will be enough.