Not sure if you are taking the piss with that question but just in case you are not; the Sapporo day return is one of the longest day returns. Add 70 minutes of duty before departing Hong Kong, and 30 minutes after returning, you'll see its a long day at work for 2 pilots.
Take a look at a map or chart. If you look to see where Hong Kong is situated relative to the city pairs you will see that flights to Manila and Taipei will be the shortest working days.
Cheers
hugo