Cultural Properties of especially high value at risk of extinction had been protected. Even by international standards, the 1950 law covered a broad spectrum of properties. The law was the basis for the establishment of the Committee for the Protection of Cultural Properties, a precursor of today's Agency for Cultural Affairs. It allowed the selection of the most important Cultural Properties, set restrictions on the alteration, repair and export of Cultural Properties and provided measures for the preservation and utilization of such properties. The regulations implementing the law specified three broad categories of properties: Tangible/Intangible Cultural Properties and Historic Sites, Places of Scenic Beauty, Natural Monuments". Tangible Cultural Properties were in this context defined as objects of "high artistic or historic value" or archaeological materials (or other historic material) of "high scholarly value". Designated buildings were required to be outstanding in design or building technique, have a high historic or scholarly value or be typical of a movement or area. A two tier system for Tangible Cultural Properties was established with the gradings: Important Cultural Property and National Treasure. The Minister of Education can designate Important Cultural Properties as National Treasures if they are of "particularly high value from the standpoint of world culture or outstanding treasures for the Japanese people". All previously designated National Treasures were initially demoted to Important Cultural Properties. Some of them have been again designated as National Treasures since June 9, 1951. Following a decision by the National Diet, properties to be nominated as World Heritage Site are required to be protected under the 1950 law. 1954 amendment With the 1954 amendment, the three categories were reorganized into four: Tangible Cultural Properties, Intangible Cultural Properties, Folk Materials (split off from the former Tangible Cultural Properties category), and Monuments (new name for the former Historic Sites, Places of Scenic beauty, Natural Monuments" category). Buried Cultural Properties were introduced as a new category, separate from Tangible Cultural Properties. In addition, a designation system was established for Important Intangible Cultural Properties and Important Tangible Folk Properties. 1966 Law for the Preservation of Ancient Capitals Particularly in the 1960s, the spectrum of protected buildings was expanded to include early examples of western architecture. Around the same time, concepts for conserving the built environment were developed. With the Law for the Preservation of Ancient Capitals from 1966, the Prime Minister could designate Preservation Districts for Historic Landscapes" or Special Preservation