Sachiko Kashiwaba is a Japanese author of children's and young adult fantasy novels, many of which have been adapted into anime films. She was born on June 9, 1953, in Miyako, a coastal city in Iwate Prefecture, Japan, and later studied at Tohoku Pharmaceutical University to become a pharmacist. Her career as a writer began while she was still a university student, when she won the 1974 Kodansha Award for New Writers of Children's Literature for her debut novel, then titled "Kichigai Tōri no Rina" (Lina on Absurd Avenue). This work was published the following year under the title "Kirino mukono fushigina machi" (The Mysterious Village Beyond the Mist).

Kashiwaba quickly became a prominent figure in Japanese children's literature, known for creating other worlds that are direct extensions of reality, where young protagonists discover important truths about themselves. Her body of work is extensive and includes novel-length fantasies, nursery tales, and series such as the long-running "Monster Hotel" books, which feature a blend of traditional Japanese spirits like kitsune and rokurokubi alongside Western-style vampires and witches. Her literary influences range from the Brothers Grimm and L.M. Montgomery to Japanese folklore collections like the "Tōno monogatari".

Kashiwaba's connection to anime began indirectly but significantly through her debut novel. The book, now known in English as "The Village Beyond the Mist," is widely reported to have inspired Hayao Miyazaki's Academy Award-winning film "Spirited Away". According to reports, Miyazaki was interested in adapting Kashiwaba's novel, and while that project did not move forward, elements from the story—particularly its setting in a traditional Japanese bathhouse (onsen) and its mysterious, grumpy elderly witch—influenced the final film. More direct adaptations followed decades later. In 2019, director Keiichi Hara released the animated film "Birthday Wonderland," known internationally as "The Wonderland," which is an adaptation of Kashiwaba's 1988 novel "Chikashitsu kara no fushigi na tabi" (Strange Journey from the Basement). The story follows a young girl named Akane who is summoned to a magical world to act as its savior, the "Goddess of the Green Wind".

A second notable anime adaptation is "The House of the Lost on the Cape" (originally titled "Misaki no Mayoiga"), a film produced by David Production and released in 2021. Based on Kashiwaba's 2015 novel of the same name, the film was part of the "Zutto Ōen Project 2011 + 10..." which marked the 10th anniversary of the Great East Japan Earthquake and Tsunami. The story directly addresses the aftermath of this disaster, following two young girls, Yui and Hiyori, who are taken in by an elderly woman named Kiwa in a mysterious house on a cape. Together, they interact with benevolent spirits from Japanese folklore, such as kappa and zashiki-warashi, to overcome demons that feed on human grief. An earlier, lesser-known adaptation was the 1998 television anime "Fushigi Mahou Fan Fan Pharmacy," based on her 1997 novel "Fan Fan Pharmacy".

A recurring theme in Kashiwaba's work is the use of fantasy to address real-life emotional challenges, particularly those faced by children and families. Her stories often explore themes of coming of age, loss, and strained family relationships, such as a daughter and father growing apart. This is especially evident in "The House of the Lost on the Cape," which she wrote as a direct response to the trauma experienced by young survivors of the 2011 Tōhoku earthquake and tsunami in her home region of Iwate. The novel was first serialized in the local newspaper of Morioka, the city where she lives, to reach children who, like the characters in her book, were dealing with grief and survivor's guilt. Her translator, Avery Fischer Udagawa, has noted that Kashiwaba hopes above all for readers to simply enjoy her books and finish them feeling that they were fun.

Kashiwaba's work has received significant recognition and numerous awards. She has won the Japanese Association of Writers for Children New Talent Award, the Sankei Children's Book Award Grand Prize, and the Shogakukan Children's Publication Culture Award. Her novel "The House of the Lost on the Cape" won the 54th Noma Children's Literature Award in 2016. Her English-translated works have also been honored internationally; "Temple Alley Summer," another novel translated by Udagawa, won the American Library Association's Mildred L. Batchelder Award in 2022, with the English translation of "The House of the Lost on the Cape" receiving an honor from the same award in 2024. Through her long career, Sachiko Kashiwaba has established herself as a foundational voice in Japanese fantasy for young readers, known for blending imaginative worlds with deep emotional resonance and a commitment to helping children navigate the complexities of life.