Your guess is correct.
I was a controller at Tokyo Air Traffic Control Center.
We had too many guys in the squadron so we worked 1 six hour shift for four days and then 3 days off.
Tokyo here we come!
JD
Yes, I enjoyed a trip to the old Johnson Air Base a number of years ago. It is now "Iruma Kichi" or "Iruma Base" of the Air Self Defense Forces, although a lot of the old buildings are still there--at least to my knowledge.
Happy Advent and (eventually) Merry Christmas!!