inquiry -- if a visa is required for transit in Japan airport

for Chinese citizen and US Green Card holder,   if taking All Nippon flight from US to China  with a transit connection stop in Tokyo (Narita airport ),    is it required to apply a visa to Japan?  The transit time is 3-hour at the same airport. 

I called the airliner and was told NO.  As long as not entering  Japan ( not going through the Customs),   no visa is needed.     But i was also told to refer to Japanese Embassy websit for official confirmation.   Not able to find out this information.   

Can anyone share if you have prior experience?  Thanks.