お札（おふだ）
Ofuda
A paper talisman, and the printed pictures that worked the same way.
An ofuda is a strip of paper or wood from a shrine or temple, written with a god’s name, pasted above a door or on a pillar to keep harm out. An omamori is the small cloth-wrapped version carried on the person. They are the ordinary countermeasure against most of what this site describes: a charm on the clothing hides a courtier from the night parade; a paper on the gate keeps a plague from the house.
Printed pictures did the same work. During the cholera epidemic of 1858 Edo bought prints of the hakutaku, the beast that knows every demon’s name, to put up at home. An 1836 broadsheet promised that any house showing the picture of the kudan would prosper; the Amabie sheet of 1846 asked to be copied and shown to people, and in 2020 it was.
Related yokai
Hakutaku
白澤（はくたく）
A beast from Chinese legend that named every harmful thing in the world for the Yellow Emperor, and whose image — nine eyes, six horns, a human face — was carried by Edo travelers and set beside pillows during the cholera epidemic of 1858.
Amabie
アマビエ
A printed sheet dated 1846 tells of a creature with long hair and a beak that rose from the sea off Higo, foretold six years of good harvests and an epidemic, and asked people to copy its picture and show it around.
Kudan
件（くだん）
An 1836 broadsheet from Tango described a kudan — a cow's body with a human face — and promised that any house that put up its picture would prosper. Other kudan of the same century foretold disaster instead.