Issun-bōshi

Issun-bōshi (一寸法師^?, "One-Sun Boy"; sometimes translated into English as "Little One Inch" or "The Inch-High Samurai") is the subject of a fairy tale from Japan. This story can be found in old Japanese illustrated book, Otogizōshi, and has been various forms around the world and is similar to the tradition of Tom Thumb in English folklore.

The general story is:

However, the one written about in the Otogizōshi has a few differences.

Other documents record similar tales and, and a tale about one who strategized to get a rich person's daughter is seen and recorded in the Shinkoku Gudo Zuihitsu written in the Edo Period.

There are also many differences in the tale depending on area.

It is unknown when the modern tale came about, but it is generally considered to have existed before the end of the Muromachi period. The theme of a "tiny child" is thought to have originated from Sukuna-hikona (meaning "small earth god": suku is "small," na is "the earth," hiko is "male god," and na is a suffix) of Japanese mythology.

Sukuna-hikona acts as a medium for the Dōjō Hōshi of the Nihon Ryōiki and Sugawara no Michizane of the Tenjin Engi (天神縁起) and is connected to the Kootoko no Sōshi (小男の草子, "Book about the Small Man") from the middle ages and the Otogizōshi of the modern ages.

It has been pointed out that just like how the nation-creator god Sukuna-hikona appeared near water, the main character of the old tale "Chiisa-ko" (small child) is in some way related to the world of water and is related to the existence of a faith in a water god. For an old couple not to have any children is an abnormality within the community and for such abnormal persons give birth in an abnormal way such as by praying to a god and giving birth from the shin to a person in the form of a pond snail, as one would find in the tale Tanishi Chōja, is the normal course for tales about heroes and children of god.

...
Wikipedia