Flag Harem, or If Her Feminine Stronghold Breaks is a harem light novel written by Ventris, who went with his pen name, Space Dragon. It is considered by many to be the quintessential deconstruction of the harem genre. Despite its initial mixed reception, Flag Harem won many awards and garnered universal critical acclaim 69 years later, and has since spawned many spin-offs, fanfictions, and video games.
Flag Harem is about a college student who has the unique ability to see people's flags, and determines their fate through the color and status of their flag over their genital area. Because of this, people have accused him of being a peeping tom and have been arrested multiple times for sexual harassment.
Flag Harem was initially met with skepticism, with the complaints being that the main character is not a high school student, and none of the character archetypes (childhood friend, tsundere, kuudere) get the D. Instead, a character, whose development was cited by others as the most development in the show, wins. The LN community then threatened to boycott the novel, which was immediately shut down.
69 years later, many reviewers revised their opinions on Flag Harem, calling it the quintessential harem light novel, citing the deconstruction concept as the key factors, its well developed characters, and the author's no-nonsense attitude to change the formula from the typical harem light novels non-patricians are used to. It currently holds an 89% on UberTomatoes.
Flag Harem currently has a live action TV adaptation in the works, a first-person shooter video game, and many fanfictions written by Smut Master Erin.