Living National Treasure (人間国宝 Ningen Kokuhō?) is a Japanese popular term for those individuals certified as Preservers of Important Intangible Cultural Properties (重要無形文化財保持者 Jūyō Mukei Bunkazai Hojisha?) by the Minister of Education, Culture, Sports, Science and Technology as based on Japan's Law for the Protection of Cultural Properties (文化財保護法 Bunkazai Hogohō?). The term "Living National Treasure" is not formally mentioned in the law, but is an informal term referencing the cultural properties designated as the National Treasures.
Before 1947, a system for Imperial Household Artists (帝室技芸員 ; Teishitsu Gigei-in) was in place.
Under the 1950 Law for Protection of Cultural Properties, intangible cultural properties are defined as dramatic, musical, artistic, and other intangible cultural artifacts of high value in terms of Japanese history or art (Article 2, Section 1, Part 2). Those intangible cultural properties of especial importance can be designated as "Important Intangible Cultural Properties" by the Minister of Education, Culture, Sports, Science and Technology (Article 71, Section 1).
In other words, intangible cultural properties are certain artistic skills. Those individuals or groups who have attained high levels of mastery in those certain skills can be designated as preservers of them by the Japanese government for the purpose of ensuring their continuation. Living National Treasure is a term for those designated as keepers of important intangible cultural properties.