Through the 1990s all of the routes to mainland China were through NRT. The first UA direct flight from the U.S. I believe was ORD-PEK around 2000 on a 772. Over the years since then, all of the mainland flights overfly NRT, except the seasonal shift of IAD-PEK to NRT-PEK.

At one time, all of the flights to China were on 744s but ORD and IAD were downguaged to 772s. China has not been the revenue generator that they had hoped for.