Korean Air Through Checking Bag
 

We have two separate Korean Air Tickets, one from Boston to Seoul we booked using Virgin Atlantic Points, the other from Seoul to Tokyo we booked directly on Korean Air's website. There is a 4 hour layover between flights. Will Korean Air be able to through-check the luggage to Tokyo in Boston even though the flights were booked separately? Will the check in counter in Boston also be able to check-in and print boarding passes for the Seoul to Tokyo flight? If not, will 4 hours be enough transit time in Seoul to go through immigration and re-check bags?

1. 4H layover is more than enough even if you need to check-in again, ICN is very efficient and KE flights most of the time on time.
2. Almost 100% certainly they will connect your bags at check-in if you present your tickets. I have done it plenty of time between KE and SkyTeam airlines when using separate tickets.

Were you able to have the luggage tagged all the way through?
i have a similar booking with two different Korean Air tickets and a 2 hour layover in ICN