To clarify about his military service situation, he does need to go before 28 if he doesnt get exemption.
Korea made a new rule last year that lets men who didnt graduate secondary schools delay till age of 35, but that rule applies only to those who were born in/after 1996..
As much as I'd love for Son to retire a WHL legend, he's only 23 now and will be a Real Madrid player before he has to enlist