The Saitama Seibu Lions are a professional baseball team in Japan's Pacific League based north of Tokyo in Tokorozawa, Saitama Prefecture. Before 1979, they were based in Fukuoka, Fukuoka Prefecture in Kyushu. The team is owned by a subsidiary of Seibu Railway, which in turn is owned by the Seibu Holdings. The team experienced a recent period of financial difficulty, but the situation brightened when the team received a record ¥6 billion posting fee from the Boston Red Sox for the right to negotiate a contract with Daisuke Matsuzaka. Between 1978 and 2008, the team logo and mascot were based on the adult version of Kimba the White Lion, a classic Japanese anime and manga series by Osamu Tezuka. In 2004, former Seibu Lions player Kazuo Matsui became the first Japanese infielder to play in Major League Baseball.

Kimba the White Lion, known in Japan as Jungle Emperor , is a Japanese shōnen manga series written and illustrated by Osamu Tezuka which was serialized in the Manga Shōnen magazine from November 1950 to April 1954. An anime based on the manga was created by Mushi Production and was broadcast on Fuji Television from 1965 to 1967. It was the first color animated television series created in Japan. It began airing in North America from 1966. The later series was produced by Tezuka Productions.