Coincidence--?

Some of my students told me today that schools in the greater Seoul area (they said Gyeonggi-do province) will now have the option of beginning classes at 9 am instead of an earlier time.  I wasn't able to determine why this option exists, but it is interesting that I ran across the following article in the American news that said students are not getting enough sleep, and for health and educational reasons American schools should consider beginning classes at a later time in the morning:

http://www.theatlantic.com/education/archive/2014/08/surprise-students-arent-getting-enough-sleep/379020/