See: https://www.reddit.com/r/JapanTravel/comments/evs3f9/japan_travel_the_2019ncov_and_you_guidelines_on/fih7ih7/
Lots of tourist attractions are closing. This list only covers up to 3/15, but says it will be updated. Tauck doesn't start visiting Japan this year until 3/23. It iwll be interesting to see what happens over the next 2 weeks...