As the boss above guestimated, probably well into 2022. Of course, I've got my hotel rooms booked for a late 2021 winter trip but in reality it'll probably be next Spring at the earliest before I'm allowed back in.
IMO, the bigger question is: When will Americans actually want to risk traveling to Japan again? We're quickly approaching half of Americans fully vaccinated and Joe Biden's new goal is to hit 70% in the next seven weeks, while the ever-efficient Japanese are hovering down in the low single-digits and desperately trailing the rest of the industrialized world. A number of family friends and their kids who currently live in Japan are working on flying back stateside to get vaccinated, since it's looking like the average Joe Blow waiting for his jab in Japan will probably still be playing with his dick well into 2022 while you can waltz into any CVS or Walgreens in America tomorrow and get vaccinated in a matter of minutes.
Add to that the hordes of Japanese citizens working in India who are fleeing the current outbreak and coming home. It's only a matter of time before that particularly nasty and deadly Indian variant makes its way to Tokyo and Osaka, if it hasn't already.
Of course, you have to factor in the economics. After the upcoming Olympics ends up a colossal failure, there'll no doubt be nationwide demand to restart tourism and recoup the billions lost in preparation for something that never happened. Maybe the government is forced to rush reopening?
At the end of the day, the fact is that right now the average Japanese citizen/resident is a far greater risk to the average American citizen/resident than vice versa. As much as I'd like a vacation, I'm happy to wait for the Japanese government to unfuck itself and then see how the upcoming Pfizer booster shots work on known variants overseas before I grab my passport and go on a pleasure tour abroad again.