20 Seiki Denki Mokuroku

is a Japanese novel written by Hiro Yuki and illustrated by Kazumi Ikeda. The novel won an honorable mention in the full-length novel category at the 8th Kyoto Animation Awards in 2017, and was the only series to win an award that year. Kyoto Animation published the novel under their KA Esuma Bunko imprint on August 10, 2018, while also announcing an anime adaptation of the novels.

Plot
The story takes place in the summer of 1907, the 40th year of the Meiji era. 15-year-old Inako Momokawa lives in the Fushimi area of Kyoto, and is the second daughter of a sake brewer. Nothing she does ever comes out right, and she receives a scolding from her father every day. Her only relief is the trust she places in her prayers to the gods. One day while at Fushimi Inari shrine, she meets a freewheeling young man named Kihachi Sakamoto. He rejects the gods, and boasts of the incoming age of electricity.

The topic of marriage suddenly comes up in Inako's household. Her father is one-sidedly making all the decisions for her, and Inako is about to give up hope. It is then that Kihachi draws out Inako's true feelings of wanting to run away from her family. The only way to stop her marriage is to find an unusual book called the "Electricity Catalog." The book is a prediction book about electricity that Kihachi wrote when he was a child, but his older brother Seiroku took the book, and its current whereabouts are unknown. Inako and Kihachi together go in search of the book across Kyoto and Shiga prefectures.