Today's Asahi publishes more details.
The current entry restrictions will be lifted for the visa holders who seek long-term residency (>3 months).
In principle, the restrictions remain the same for short-term visitors (=< 3 months).
There will be an additional quota of 1,000 arriving foreign nationals per day, in addition to returning Japanese and non-Japanese residents.
All incoming travelers are requested to self-quarantine for 14 days upon arrival (if tested corona-negative at the port of entry. If positive, you will be isolated in a special hotel or a hospital).
Further relaxation to the entry restrictions is being planned for the entries from "16 countries" (Australia, Brunei, Cambodia, China, Hong Kong, Laos, Macau, Mongolia, Malaysia, Myanmar, New Zealand, Singapore, South Korea, Thailand, Taiwan, Vietnam).