Question: Miho Obana, is a shōjo manga artist born in Tokyo, Japan, her best-known work was "Kodoma no Omocha", also known as "Kodocha", which was published in Ribon, a monthly Japanese shōjo manga magazine published by who?
Sentence (from "Ribon"): First issued in August 1955, its rivals are "Nakayoshi" and "Ciao".
Relevant evidence: No