Furu-utsubo or Utsubo is a Japanese yokai (ghosts, spirits and monsters) portrayed in Sekien TORIYAMA's yokai art collection book named "Hyakki Tsurezure Bukuro" (The Bag of One Hundred Random Demons; the term 'hyakki' in its title is a pun on the usual hyakki, replacing the character for demon which is written as "鬼" in Japanese with a character for vessel written as "器," and sure enough, most of the yokais shown in this book are tsukumogami [a type of Japanese spirits that originate in items or artifacts that have reached their 100th birthday and become alive]). A utsubo refers to an arrow quiver to be carried on the back. According to the expository writing of "Hyakki Tsurezure Bukuro," the 'Furu-utsubo' (an old quiver) used to belong to Yoshiaki MIURA who shot yakan (Buddhist legendary animals, which initially referred to jackals in India and later foxes in Japan) in Nasunogahara fields. It is said that the yokai 'Furu-utubo' is one of the tsukumogami which was transmuted from the Miura no suke's quiver and started to move around like a beast.
Together with Kazusa (no suke) (deputy governor of Kazusa Province) Hirotsune, Miura no suke allegedly shot down a nine-tailed fox in Nasunogahara. Some say that his quiver turned into yokai because his past glory had been forgotten as time passed. Generally, arrow quivers were made of lacquered bamboo, but some of them had fur or feathers applied inside. One theory has it that items including animal body parts are more prone to transmuting into tsukumogami.