Despite a historically strong Chinese influence, Korean culture has shaped its own unique identity. It came under attack during the Japanese rule from 1910 to 1945, when Japan enforced a cultural assimilation policy. Koreans were forced to learn and speak Japanese, adopt the Japanese family name system and Shinto religion, and were forbidden to write or speak the Korean language in schools, businesses, or public places.
After the peninsula was divided in 1945, two distinct cultures formed out of the common Korean heritage. North Koreans have little exposure to foreign influence. The revolutionary struggle and the brilliance of the leadership are some of the main themes in art. "Reactionary" elements from traditional culture have been discarded and cultural forms with a "folk" spirit have been reintroduced.
Korean heritage is protected and maintained by the state. Over 190 historical sites and objects of national significance are cataloged as National Treasures of North Korea, while some 1,800 less valuable artifacts are included in a list of Cultural Assets. The Historic Sites and Monuments in Kaesong and the Complex of Goguryeo Tombs are UNESCO World Heritage Sites.
North Korea shares the Korean language with South Korea, although some dialectal differences exist within both Koreas. North Koreans refer to their Pyongyang dialect as munhwaŏ ("cultured language") as opposed to the dialects of South Korea, especially the Seoul dialect or p'yojun'ŏ ("standard language"), which are viewed as decadent because of its use of loanwords from Chinese and European languages (particularly English). Words of Chinese, Manchu or Western origin have been eliminated from munhwa along with the usage of Chinese hancha characters. Written language uses only the chosŏn'gŭl (Hangul) phonetic alphabet, developed under Sejong the Great (1418–1450).