According to Japanese folklore, a shōgorō is a kind of tsukumogami, a spirit which inhabits a household item. In this case, it is an animated shōgo (鉦吾) — a small, bowl-shaped gong that is struck with a mallet and used in Buddhist services. A shōgo gets a lot of use, being used multiple times every service. It is made of metal, and so can last a long time before breaking. A gong which has long worn out and stopped playing its note pleasantly, and gets put into storage until it is forgotten (or perhaps one is the witness to some horrible crime) is an ideal candidate for awakening into a yokai.

Like nay tsukumogami, shōgorō are not dangerous. At most, they are startling, as they wander around at night like some kind of metal turtle, striking their bodies and ringing their notes out into the night. It is enough perhaps to cause loss of sleep, but not much else.

The name shogorō is a pun. It is a combination of shōgo, the gong, and gorō, a very common part of a boy’s name. The word can also be read as a combination of shōgo and goryō (御霊), the ghost of a noble or an aristocrat from ages past. Goryō are a grade of ghost above yūrei, and play a large part in many Japanese ghost stories.

In the early 18th century, there was a wealthy merchant family called Yodoya living in Osaka. For many generations, the Yodoya were the kings of the rice trade, raking in unbelievable amounts of cash. The 5th generation boss, Yodoya Tatsugorō, had so much money and lived a life of such extreme opulence that he attracted the attention of the bakufu (regional shogunate officials, something like military police).

The bakufu decided that the Yodoya family had accumulated too much wealth. They were only a merchant family, and it was improper for a lower class to hold so much wealth. Their economic power was above their station in life, and so the bakufu stripped Yodoya Tatsugorō of everything he had: his rice, his business, his house, his every last possession. The Yodoya family fell into ruin, and Tatsugorō became destitute. Even his favorite possession, an unbelievably rich and indescribably splendid golden chicken called kogane no niwatori (金の鶏, literally “golden chicken”), was taken from him. The loss of his precious golden chicken caused Tatsugorō so much grief that he died, and because of the unhappy circumstances of his death, his ghost was unable to pass on.

Normally, when a ghost lingers like this, it attaches itself to the object of its desire, be it a person, a place, or (in this case) a thing. Tatsugorō’s soul meant to attach itself to his precious kogane no niwatori. In Japanese, the words for "gong" and "golden" can both be read "kane". Poor Tatsugorō’s ghost must have gotten confused and attached itself to a nearby shōgo instead of his chicken, and the instrument turn into a tsukumogami.