Takei was born in Suwa, Nagano prefecture in 1894. After studying at the Hongo Yoga Kenkyujo (Hongo Research Institute for Western Art) he entered the Western-style art department of Tokyo Art School in 1919. He was an ardent admirer of illustrator Takehisa Yumeji and poet Kitahara Hakushu. After graduation from art school, he married in 1921 and to support his new family he began to produce illustrations for children for Kodomo no tomo [Child's Friend], a children's magazine published by Fujin no Tomo Sha. In 1922 he became one of the leading illustrators for Kodomo no kuni [Children's Land] from its inaugural issue. In 1923 he published Otogi no tamago [The Fairy's Egg], and in 1925 his first individual exhibition was held in Ginza in the heart of Tokyo. His Ramu-ramu O [King Ramu-ramu] came out in 1926. The following year, with Shimizu Yoshio, Okamoto Kiichi, Kawakami Shiro, and other illustrators contributing to the Kodomo no kuni, Takei formed the Nihon Doga Kyokai (Japan Association of Illustration for Children), as part of the effort to achieve artistic quality in illustrations for children. Following Okamoto's death, Takei succeeded him as critic and selector of illustrations submitted to Kodomo no kuni in 1931. In 1955, he became editorial adviser for the magazine Kinda bukku [Kinder Book].
And about the site that houses 9000 images from the almost 300 issues of Kodomo no kuni: "This program was created as part of the Picture Book Gallery project of the International Library of Children's Literature to introduce in digital form the story of the picture book genre from its beginnings until the present. The program was designed to reproduce the works contained in the journal Kodomo no kuni[Children's Land] and convert them to digital images, which have been edited and titled and made available to the public as a virtual exhibit."
Some of Takei's books have been reprinted and are available from amazon.co.jp.