There are 42 entries of shrine structures designated as National Treasures of Japan. The term "National Treasure" has been used in Japan to denote certain cultural properties since 1897. The number of Shinto shrines in Japan today has been estimated at more than 150,000, with single-structure shrines being the most common. Shrine buildings might also include oratories, purification halls, offering halls called heiden (between honden and haiden), dance halls, stone or metal lanterns, fences or walls, torii, and other structures. Shrine structures were designated national treasures when the Law for the Protection of Cultural Properties was implemented on June 9, 1951. As such they are eligible for government grants for repairs, maintenance, and the installation of fire-prevention facilities and other disaster-prevention systems. The shrine structures designated as national treasures date from the 12th-century Classical Heian period (example pictured) to the early modern 19th-century Edo period. (Full list...)