Oam Monogatari: Sono Natsu, Watashi ga Shitta koto is a oNA (web) anime that premiered in spring 2018, produced by Asura Film.

About the production: the story comes from a other, there is 1 episode of about 9 minutes and its current status is "finished".

On AniList, Oam Monogatari: Sono Natsu, Watashi ga Shitta koto has an average score of 51%, an average score, and appears on 490 users' lists.

A tourism promotion anime for Ogaki City in the Gifu Prefecture. It is based on Oam Monogatari, a book about a woman who spent her coming-of-age during the Sengoku Era. Oam is the main character and is the daughter of Yamada Kyoreki who is a vassal to the warlord Ishida Mitsunari. It offered one of the few historical viewpoints of an noble teen/woman's life during the wars. The anime jumps between past the present as we learn about Oam's struggles at Ogaki Castle (which would become ground zero for Battle of Sekigahara which established Tokugawa as the shogunate), and how Oam escaped with her mother in the dead of night.

Official synopsis from AniList.