(オセロ?) is a shōjo
manga series by Satomi Ikezawa. It was originally serialized by Kodansha in Bessatsu Friend
and collected in seven tankōbon
volumes. It is distributed by Del Rey Manga in North America. The story is about a shy, naive Japanese teenager with a split personality.
The manga is titled after the board game Othello, and not the Shakespearian play. The game involves a lot of switching back and forth between black and white pieces, representing Yaya and Nana's constant flip-flop.
Yaya is a shy, quiet teen with a passion for singing, J-rock, gothic lolita, cosplay and music in general. But she has a secret: When she looks in a mirror or hits her head, Yaya's second personality, aptly named Nana, takes over her body and puts the wrong-doers in their places, shouting her catchphrase "Heavenly Punishment!" and once the damage is dealt, "Justice is done!"
The series chronicles Yaya and Nana's somewhat episodic adventures against bullies, perverts, and generally mean people. The manga also has a lot to do with music, as several of the characters have connections to the music industry or play in a band.
Though this is a different manga, Pon-chan (another manga, Guru-Guru Pon Chan, by the same author) shows up.