Year 24 Group (24年組 Nijūyo-nen Gumi) refers to one of two female manga artist groups which are considered to have revolutionized shōjo manga (girls' comics). Their works often examine "radical and philosophical issues", including sexuality and gender issues, and many of their works are now considered "classics" of shōjo manga. Many of those in the first group, Fabulous Year 24 Group (花の24年組 Hana no Nijūyo-nen Gumi), also known as the Forty-Niners, were born in Shōwa 24 (1949). The exact membership is not precisely defined, but includes Yasuko Aoike, Moto Hagio, Riyoko Ikeda, Yumiko Ōshima, Keiko Takemiya, Toshie Kihara, Ryoko Yamagishi, Minori Kimura, Nanae Sasaya, and Mineko Yamada. A second group, known as Post Year 24 Group (ポスト24年組 Posuto Nijūyo-nen Gumi), includes Wakako Mizuki, Michi Tarasawa, Aiko Itō, Yasuko Sakata, Shio Satō, and Yukiko Kai. The Year 24 Group significantly contributed to the development of subgenres in shōjo manga, The Year 24 Group used bildungsroman genre conventions in their works. Stylistically, the Year 24 Group created new conventions in panel layout by departing from rows of rectangles that were the standard of the time and using panel shape and configuration to convey emotion, and softening or removing panel borders. At around the same time as the year 24 group were creating manga, shōjo manga magazines began serialising on a weekly basis. Moto Hagio and Keiko Takemiya lived in the same apartment in Ōizumi in Nerima, Tokyo from 1970 to 1973, in a situation similar to Osamu Tezuka's Tokiwa-so. Takemiya's friend Norie Masuyama lived nearby and was described by Moto Hagio as Takemiya's "brain staff". Masuyama was not a manga artist herself, but she introduced Takemiya to male homosexuality for women via Barazoku, which inspired Takemiya and Hagio to create shōnen-ai works. Comiket, the world's largest comic convention, was started by the dojinshi circle Meikyu (迷宮), which began as a group for studying the works of various manga artists, including Moto Hagio. Works by Hagio and Satō were included in the shōjo manga anthology Four Shōjo Stories, published in North America by Viz Communications in 1996.