was a after Meiwa and before Tenmei. This period spanned the years November 1772 through March 1781. The reigning emperors were and .
Change of era
- 1772 : The era name was changed to An'ei (meaning "peaceful eternity") to mark the enthronement of Emperor Go-Momozono and in hopes of turning attention from the serial catastrophic devastation from fires and storms in Meiwa 9. The previous era ended and a new one commenced in the 11th month of Meiwa 9.
Events of the An'ei era
- 1775 (An'ei 4): Epidemic diseases spread across the country – in Edo alone, an estimated 190,000 perished.
- 1775 (An'ei 4): Swedish physician and botanist Carl Peter Thunberg arrives at VOC outpost or "factory" in Nagasaki bay; and ultimately, his scientific activities will result in the first detailed, descriptive survey of the flora and fauna of the Japanese archipelago.
- 1778 (An'ei 7): Kyoto suffers a massive flood.
:Bakufu policy in this era was designed to marginalize the influence of foreigners in An'ei Japan; however, an unintended and opposite consequence of sakoku was to enhance the value and significance of a very small number of thoughtful observers like Thunberg and Titsingh, whose writings document what each scholar learned or discovered first-hand. Thunberg's and Titsingh's published accounts and their unpublished writings provided a unique and useful perspective for Orientalists and Japanologists in the 19th century; and the work of both men continues to be rigorously examined by modern researchers today.
- 1780 (An'ei 9): Heavy rains and floods in the Kantō necessitate extensive government relief in the flood-stricken areas.