Among buildings, which belong to Shintoism, the Haiden (worshipping house) is most characteristic, especially from the viewpoint of theory of architectural space. Most Shinto-shrines of the recent ages, except for very small ones, has necessarily its Haiden, which stands at the forecourt of shrine itself and is used for the place of priests or worshippers. But the origin of Haiden has been obscure hitherto. So, I traced it. The oldest document which used the word "Haiden" is the governmential notification concerning Shinto-buildings dated A.D. 771. But that the notification should be a forgery is decisive today. When we eliminate it from the problem, we can scarcely find out any Haiden on documents from ninth to eleventh century. We find, however, the word "Raiden" (saluting house) instead of it. I cite ten examples of Raiden, and eight of them belonged to Shinto-shrines and two belonged to Buddhist tombs. Functions of the Raiden seem to be same as that of Haiden, and, furthermore, as that of the "Raido" (saluting hall) which was frequently attached to Buddhist temples of contemporary and antecedent periods. And, generally, Shinto-shrines which possessed Raidens had been strongly influenced by Buddhism. So, I presume that the Raiden in Shintoism was a transperence from Raido in Buddhism. We find the word "Haiden", for the first time, on a document of the end of eleventh century. And I cite seventeen examples of Haiden from documents of twelfth century, and, thereafter, the word has been used more frequently as everybody knows. The word Haiden of twelfth century, concerning some of above examples, was new name for old Raiden. But it was, concerning other examples, another name of "Maidono" (dance house), which had been a pavillion with no wall standing independently at the forecourt of the Shinto-shrine since about ninth century. Growth and supplanting of another name "Haiden" were, surely, caused by popularization of indoor rites in Shintoism. So, we can conclude that the Haiden came into existence consisting of two antecedents, e.i. the Raiden and the Maidono, about in eleventh or twelfth century.
