The Imperial Household Agency (Kunaicho 宮内庁), the independent agency that organizes the life and the duties of Imperial Family, has closed the Imperial Palace, East Gardens and other places to visitors.
The Public Viewing of the Imperial Throne and Other Ceremonial Items, which was scheduled from March 1st at Kyoto Imperial Palace, has been postponed due to fear of spreading Novel Coronavirus. The rescheduled term will be informed as soon as it is decided
Full text here: https://www.kunaicho.go.jp/e-event/Imperial-Throne-r02.html
Here others decision of public closure: