Keita Suminoe is a third-year Japanese middle school student living with his father, stepmother, and older twin stepsisters, Ako and Riko. Since the remarriage of their parents at childhood, the siblings have always been affectionately close and supportive of one another. Nowadays the trio see their opposites in a noticeably less platonic fashion; Ako and Riko frequently flirt and lust after Keita while, much to his stress, he fights the urge to give in to them.
Kiss×sis began as a series of one-shots in January 2004 by Bow Ditama, an illustrator known for his work on Mahoromatic, published by Kodansha in their now-defunct bimonthly Bessatsu Young Magazine, a manga magazine aimed at a mostly adult male audience. Kiss×sis transferred to Weekly Young Magazine in September 2008, and again transferred to Monthly Young Magazine on December 9, 2009. It had been on a hiatus from the magazine between the August 2013 and January 2014 issues. The first tankōbon volume was released on September 6, 2007 by Kodansha under their KC Deluxe imprint, with 22 volumes released as of March 6, 2020. The manga is also licensed in Taiwan by Sharp Point Press.
Anime
It was announced in June 2008 that an animated adaption of Kiss×sis would be produced by Feel. On December 22 of that year, the first OVA was released, bundled with the third volume of the manga, directed by Munenori Nawa. Subsequent releases were packaged with subsequent volumes of the manga. The 12th and last episode was released on April 6, 2015. The opening and closing themes for the OVA include "Our Honey Boy" by Ayana Taketatsu and Yuiko Tatsumi and "Starry Sky Story" by Nana Takahashi, respectively. A 12-episode anime television series adaptation of the manga aired on AT-X from April 5 to June 21, 2010. A censored pre-release of the first episode aired online on March 28, 2010. The opening theme is "Balance Kiss" performed by Ayana Taketatsu and Yuiko Tatsumi, and the ending theme is "Our Steady Boy" by Yui Ogura and Kaori Ishihara. The ending theme for episode 12 is "Futari" by Yui Ogura and Kaori Ishihara. The first DVD volume was released on June 23, 2010. Unlike the TV airings of the other episodes, certain scenes of episodes nine through twelve were censored. A DVD/Blu-ray Disc edition has subsequently been released without the censorship.
