mar 19, 1684 - In Japan, the Tenna era ends on the 21st day of the 2nd month of the Chinese calendar of the 4th year of the Tenna era and the Jōkyō era begins as Japan's royal astronomer, Shibukawa Shunkai institutes the Jōkyō calendar to replace Chinese calendar which had been used in Japan since 859 AD, after calculating that the length of the solar year is 365.2417 days
Added to timeline:
Date:
mar 19, 1684
Now
~ 340 years ago
