Abumikuchi is a Japanese specter in "Hyakki Tsurezure Bukuro" (One hundred bags in idleness), a collection of specters illustrations by Sekien TORIYAMA.
It is a kind of Tsukumo-gami (gods to a variety of things), specifically the one transformed from abumi (stirrups.)
According to Shigeru MIZUKI, a Japanese cartoonist specializing in specters, Abumikuchi was originally a stirrup used by a busho (Japanese military commander.)
The abumi was supposed to share the same fate with the owner, but he was killed in battle and the abumi was left in the field,
The abumi turned into a specter, and is waiting in vain for its owner as a dog waits for its owner.
However this folk story is not written in the original book "Hyakki Tsurezure Bukuro" (One hundred bags in idleness), and Kenji MURAKAMI, a tourist of a specter, says that Sekien created the story as an explanation of the illustration.