Guri and Gura  The stories tell of the encounters of twin anthropomorphic field mice, Guri and Gura. Yamawaki accompanies Nakagawa's loosely structured narratives with simple, unsophisticated illustrations. The stories aim at entertaining rather that instructing and thus do not feature moral dilemmas to be overcome. The first volume of the series, titled "Guri and Gura", appeared in the children's magazine "Kodomo no Tomo" in 1963. The series' writer Rieko Nakagawa worked in childcare at the time. As of 2014, the first volume had sold over four million copies, and the series had sold a combined 24.9 million copies worldwide. The first English of "Guri and Gura" appeared in Britain in 1967; in this translation the castella cake the mice make in the original Japanese becomes a sponge cake more familiar to a British audience. An translation appeared in 1991 under the subtitle "The Giant Egg", by an uncredited translator. Later translations have been by Peter Howlett and Richard McNamara. Dozens of other translations have appeared, including Korean, French, Portuguese, Thai, and Esperanto.