Short answers, pulled from the story.
Shojo manga is an editorial category of Japanese comics targeting adolescent girls and young adult women. It is one of the four primary editorial categories of manga, alongside shonen (targeting adolescent boys), seinen (targeting young adult and adult men), and josei (targeting adult women).
Shojo manga originated from Japanese girls' culture at the turn of the twentieth century, primarily shojo shosetsu (girls' prose novels) and jojoga (lyrical paintings). The first exclusively shojo magazine was published in 1902, and early shojo manga began a distinct period of creative development in the 1950s.
The Year 24 Group was a generation of shojo manga artists who emerged in the early 1970s, including Moto Hagio, Keiko Takemiya, and Yumiko Oshima. Their works focused on internal psychology and introduced new genres such as adventure fiction, science fiction, fantasy, and historical drama to shojo manga, pioneering visual styles that later spread across manga categories.
The Rose of Versailles by Riyoko Ikeda, published from 1972 to 1973, became the first major critical and commercial success in shojo manga. It was groundbreaking for its portrayal of gender and sexuality and was influential in its depiction of bishonen, a term for androgynous male characters.
The large-eye style was established by lyrical painter Macoto Takahashi, who incorporated Jun'ichi Nakahara's doll-like eye style into his manga and added stylistic innovations such as dots, stars, and multiple colors for the iris. At the end of the 1950s, Miyako Maki adopted this style and spread it into mainstream shojo magazines.
Female artists came to dominate shojo manga beginning in the 1960s, emerging from reader submission contests run by weekly magazines such as Shojo Friend and Margaret. Their rise led to significant creative innovation, including the development of romantic comedy manga, more complex depictions of gender and sexuality, and thematically complex narratives. Since the 1970s, shojo manga has been written almost exclusively by women.