OP, check all of the other major cities in Asia that ANA would connect to, almost every UA/NH fare I've seeb TPAC allows stopovers in Tokyo for $100, so if for example a P fare ex YVR or SEA to PVG or PNH fits your budget then you just have to fly there and turn around after your lectures are over. TYO is usually the most expensive point in East Asia. Usually you can do better ticketing to somewhere else and using the stopover option.