The Imperial Seal - Oomishirushi

…In ancient times, temples would recite the Great Perfection of Wisdom Sutra, the Niō Sutra, and other sutras many times, and distribute a scroll that recorded the number of times it had been recited to those who requested prayer. Ise Jingū followed this example early on, reciting the harae-kotoba (prayers for purification) many times and distributing o-harae-tamas for the thousand and ten thousand purifications. At the shrine, it was called o-mishirushi (Great Seal) and was affectionately called o-harae-san (purification san) or o-jingu-san (Great Shrine san). It was already recorded in the Kamakura period, and was distributed throughout the country by the shrine's priests. …

*Some of the terminology explanations that refer to the "Imperial Seal" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…古来，寺院では大般若経，仁王経などを何度も読誦し，その回数を記した巻数（かんず）を祈禱依頼者に配ったが，伊勢神宮もはやくからこれにならい，祓詞（はらえことば）を何度も修して千度祓，万度祓のお祓大麻を配った。神宮では〈大御璽（おおみしるし）〉と称し，〈お祓さん〉とも〈大神宮さん〉とも親しみを込めて呼ばれた。鎌倉時代にはすでに記録に見え，神宮に所属する御師の手によって全国に配布された。…

※「大御璽」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報