In an alternative feudal Japan, a strange disease that only affects males caused a massive population reduction, leaving females to fill the vacant jobs, therefore changing the social structure. Now, 80 years after the initial outbreak with a 1:4 male:female ratio, Japan is a completely matriarchal society. Females hold all important political positions, and males are their consorts. Only the most powerful female--head of Tokugawa shogunate--may keep a harem of handsome and unproductive males, known as "Oooku."

Note: Won an Excellence Prize at the 2006 Japan Media Arts Festival and a special prize at The Japanese Association of Feminist Science Fiction and Fantasy’s fifth annual Sense of Gender Awards in 2005.
Won the Tezuka Osamu Cultural the Grand Prize in 2009 and the 56th Shogakukan Manga Award in Girls’ Category in 2011.
Was nominated for the first annual Manga Taishō in 2008.