Bicycles can go on national highways, so special tagging is unnecessary.
So I just removed the "street=自転車通行可" tag.
But I tagged some ways with  "bicycle=yes" because the note may be effective on roads that cross mountain passes.
https://www.openstreetmap.org/changeset/155000805#map=12/34.6811/135.8721
https://www.openstreetmap.org/changeset/155000887#map=16/34.6930/135.8359