  thumb|x rating symbol used by the motion picture association of america from 1968 to 1990 in some countries, x or xxx is or has been a motion picture rating reserved for the most explicit films. films rated x are intended only for viewing by adults, usually legally defined as people over the age of 18 or 21. ==australia== the australian classification board (acb), a government institution, issues ratings for all movies and television shows sold or aired. material showing explicit, non-simulated sex that is pornographic in nature is rated x18+. people under 18 may not buy, rent, exhibit or view these films. the exhibition or sale of these films to people under the age of 18 years is a criminal offence carrying a maximum fine of $5,500. films classified as x18+ are banned from being sold or rented in most australian states. they are legally available to be sold in the australian capital territory and the northern territory. importing x18+ material from these territories to any of the australian states is legal, as the constitution forbids any restrictions on trade between the states and territories. the x18+ rating does not exist for video or computer games. ==france== films may be shown in theaters in france only after classification by an administrative commission of the ministry of culture. in 1975, the x classification (officially: "pornographic or violence-inciting movies") was created for pornographic movies, or movies with successions of scenes of graphic violence. the commission has some leeway in classification, it may for instance take into account the artistic qualities of a movie not to count it pornographic. movies with an x rating may only be shown in specific theaters (which hardly exist nowadays in france); they bear special taxes and tax rates, including a 33% tax on revenue. in 2000, some conservative associations sued the government for granting the movie baise-moi, which contained graphic, realistic scenes of sex and violence, a non-x classification. the conseil d'Ãtat at litigation ruled that the movie should have been rated x. the decision was highly controversial, and some suggested changing the law under which it was rated 18. ==united kingdom==  the original x certificate, replacing the h certificate, was issued between 1951 and 1982 by the british board of film censors in the united kingdom. it was introduced as a result of the wheare report on film censorship. from 1951 to 1970, it meant "suitable for those aged 16 and over," and from 1970 to 1982 it was redefined as meaning "suitable for those aged 18 and over". the x certificate was replaced in november 1982 by the 18 certificate. sometimes the rating of a film has changed sign
British_Board_of_Film_Classification Film_censorship Motion_Picture_Association_of_America Motion_picture_rating_systems Self-censorship