MM 572 then KE 552 at Narita
Sapporo → Tokyo → Seoul
Timetable, Tokyo time
12:20MM 572 from Sapporo at the gate
19:01KE 552 to Seoul leaves the gate
6 h 41 apart on the timetable
The last days
MM 572 and KE 552 weren’t both flown 15 min to 12 h apart in the last 21 days.
Statistics from past flights, not live flight information. Always check times and your connection with your airline, and don’t base travel or booking decisions on these numbers.