FlyerTalk Evangelist
Join Date: Aug 2011
Location: Barcelona, London, on a plane
Programs: BA Silver, TK E+, AA PP, Hyatt Globalist, Marriott LT Plat, Hilton Diamond
Posts: 13,048
It's always possible that somebody booked Japan a year in advance and then finds that they can't make it and cancels. The award seats may or may not pop back up.
Seoul is also a nice place to spend a couple of days though. Worst case scenario is you fly there a couple of days early and enjoy a 2-country holiday.