Jaiko Gouda is the younger sister of Gian. Her first appearance was in the first chapter of the manga.
She is a short and fat girl with short black hair (brown in the 1979 anime). She usually wears a red overall skirt and white top underneath in the 1979 anime. In the 2005 anime, she has a green top with a flower on it.
An aspiring mangaka, Jaiko goes by her amateur Mangaka mangakastyle pen name Christine Goda (クリスチーネ 剛田 Kurisuchīne Gōda), and sometimes submits her manga to publishing companies for prizes. She mostly fails in these contest because her storytelling is still rough. After that when she decides to give up writing comic books, Gian's friends are asked/forced to cheer her up. She has a crush on Moteo Mote, a seventh grader in the school. She is sometimes referred to as Hana.
She loves to write comic books and draw. In the future, she will be a famous writer with lots of copies of her comic books sold.
In the American English dub, her nickname is changed to Little G.
Jaiko appeared in the 1973 anime, but she made very few appearances in it.