For thousands of foreigners and also for many Japanese, reopening the border of Japan is an issue. Japan has closed her border since March 2020 and most of the foreigners cannot enter for short stay term. Then, there are regulations entering Japan too.
Recent news say that Japan is considering to reopen her border in spring 2021. However,definitely not for all nationalities immediately. It is obvious that countries will be selected according to the fact sheets of COVID-19. States which have relatively less number of patients and low death rates will be the ones to be chosen.
These countries will be Republic of China(Taiwan), Thailand, Vietnam, Republic of Korea(South Korea), and New Zealand. Then, low risk countries will follow. Anyway, no one in Europe plans a trip to Japan just a few weeks ahead. Usually it is several months and probably it is a time now to prepare. The reason is simple. If you want to travel more than a week, Japan is one of the few countries at this moment which is low risk and also a place where you can easily enjoy.