See woodblock image at: Ronin gallery ‘s woodblock print by Yoshitoshi
Chinsei Hachiro Tametomo was a celebrated historical figure of the 12th century, whose enemies exiled him to the island of Oshima off the coast of Japan. There according to legend, he repelled the demon of smallpox who was preparing to invade the island. In his response to his ferocious threats, the demon shown in the left of the woodcut is reputed to have been diminished to the size of a pea and floated out to sea. c1847-1852
History of the smallpox demon in Japan
In Japanese, the word hōsōshin (疱瘡神 (ほうそうしん）) translates literally to “smallpox god”. According to the Shoku Nihongi, smallpox was introduced into Japan in 735 into Fukuoka Prefecture from Korea. In those days, smallpox had been considered to be the result of onryō, which was a mythological spirit from Japanese folklore who is able to return to the physical world in order to seek vengeance. Smallpox-related kamis include Sumiyoshi sanjin  In a book published in the Kansei years (1789–1801), there were lines that wrote that smallpox devils were enshrined in families which had smallpox in order to recover from smallpox.
Customs related to smallpox devils
Smallpox devils were said to be afraid of red things and also of dogs; thus people displayed various dolls that were red. In Okinawa, they tried to praise and comfort devils with sanshin, an Okinawan musical instrument and lion dances before a patient clad in red clothes. They offered flowers and burned incense in order to please smallpox demon. In Okinawa, there was smallpox poetry in Ryuka; the purpose of smallpox poetry in the Ryukyu language is the glorification of the smallpox demon, or improvement from deadly infection of smallpox.  There is a collection of smallpox poetry including 105 poems published in 1805. Traditional smallpox folk dances have been observed even in present-day Japan, including Ibaragi Prefecture andKagoshima Prefecture, for the avoidance of smallpox devils.