The Japanese government is considering the implementation of a COVID-19 measure to limit entry into the country to 2,000 travelers per day. Japanese citizens and permanent residents will also be subject to the daily cap on travelers entering Japan. The separate measure for travel into the country for essential business travel from Singapore, China and several other countries will continue to be suspended for the time being.
Additionally, under the new proposed COVID-19 measures which are being discussed, all travelers (regardless of nationality or residency status) will be required to provide proof of a negative COVID-19 test result within 72 hours prior to departure and be subject to a 14-day self-quarantine. The Japanese government is also preparing to introduce a new smartphone application for daily video calls to monitor health of entrants into the country during the 14-day self-quarantine.
For additional information see the relevant materials (in Japanese) published by the Novel Coronavirus Response Headquarters (新型コロナウイルス感染症対策本部) and the initial report published by Nikkei on the above potential measures.