I have been reading posts here and there and looked at airline route maps. I noticed a similar pattern between Japan and the U.K.
Many flights to south Asian countries from the U.S. often seem to stop in Japan and then 2 hours later move on to there final destination. For example.... LAX-KIX-BKK or MSP-NRT-BKK.
On the other side of the country, flight to Southwest Asia, parts of Africa and the Indian Sub-continent often seem to stop in the U.K. for 2 hours and move on to their final destination. For example.... JFK-MAN-Karachi.
What I am wondering is the similarity a coincidence or a planed strategy to better facilitate operations? Finally is there another situation similar to this?