(Information sharing because the information as of now is available in Japanese only)

Japan will ban entry from those who was in the listed countries within 14 days from the date of entry, and the listed countries are as follows:

Asia: Indonesia, Singapore, Thailand, South Korea, Taiwan, China (including Hong Kong and Macau), Philippine, Brunei, Vietnam, Malaysia

Oceania: Australia, New Zealand

North America: Canada, USA

Latin America: Ecuador, Chile, Dominican Republic, Panama, Brazil, Bolivia

Europe: Iceland, Ireland, Albania, Armenia, Andorra, Italia, UK, Estonia, Austria, Netherland, North Macedonia, Cyprus, Greece, Croatia, Kosovo, San Marino, Switzerland, Sweden, Spain, Slovakia, Slovenia, Serbia, Czech Republic, Denmark, Germany, Norway, Vatican, Hungary, Finland, France, Bulgaria, Belgium, Poland, Bosnia and Herzegovina, Portugal, Malta, Monaco, Moldova, Montenegro, Latvia,  Lithuania, Liechtenstein, Romania, Luxembourg

Middle East: Israel, Iran, Turkey, Bahrain

Africa: Egypt, Ivory Coast, Democratic Republic of the Congo, Mauritius, Morocco

Japan will ban entry of foreigners who hold passports issued at Hunan and Zhejian Provinces of China and foreigners boarded the Westerdam from Hong Kong

 

Foreign nationals leaving Japan after April 3 for the listed countries are subject entry refusal even though they have re-entry permit (including special re-entry permit).

For “Permanent Resident”, “Spouse of Japanese”, “Spouse of Permanent Residence” and “Long-term Resident” who left Japan before April 2 with reentry permit (including special re-entry permit), the Immigration will grant that there is a special reason. (That’s literary description in Japanese, but it seems those status-based foreign residents who left Japan before April 2 with re-entry permit may enter Japan with special reason)

http://www.moj.go.jp/content/001316538.pdf