Most famous for his series Fuku-chan, Ryuuichi Yokoyama was a mangaka and animator most active from the 1930s-early 1950s. A pioneer of gag manga, Yokoyama and his cohorts (collectively referred to as the "Shin Manga-ha Shuudan" or "New Manga Group" ) stood out in the 1930s as the majority of mangaka were creating political cartoons. Yokoyama has often been cited as a significant influence on Osamu Tezuka, and even Tezuka's signature beret was preceded by the berets worn by Yokoyama and the Shin Manga-ha Shuudan in the early 1930's.

In 1956, Yokoyama also founded Otogi Production, an early anime studio most famous for its TV shorts series Instant History. Aired from spring 1961 through winter 1962, Instant History preceded even Osamu Tezuka's famous Astro Boy TV anime, which would in 1963 become the first TV anime to run in a 30-minute time slot.

On November 8, 2001, Yokoyama died of cerebral infarction at the age of 92. In 2002, a museum memorializing his life and work opened in his hometown of Kochi.