Originally Posted by jsimon926

This is not true. If you were in a "yellow" country prior to 14 days upon arrival to Japan and did not receive 3 doses of an approved vaccination, you would be required to quarantine upon arrival. This means you cannot take public transportation in accordance with the "Pledge" (health attestation).

I would, however, take all of this information with a grain of salt unless you plan to go to Japan in the next few months. The country is fairly slow with updating their documentation as their health pledge was last revised on April 15th.