私印論（Ⅳ. 論考 / 2. 古代印論 : 出土・伝世印と印影）

日本古代の印章は，印影や現存印を含めても相当数にのぼり，大きく官印と私印，寺社印の三つに分類できる。そのうち，官印には法令に規定のある公印とそれ以外に分けられ，私印も家印と個人印に分けられる。ただ，印の押し方は公文書・私文書を問わず，同じように，文字のあるところに全面に押されている。貞観年間になると，それまで私文書にしか押されなかった私印が封家の発給する文書にも押されるようになった。現存の古文書などから使われ方を見ると，寺社印と家印は公印的に用いられることが多いが，私印は様々である。特に，公的家を持ちうる貴族層では，家印と個人印の区別がつきにくい。中には，個人の名前を刻した印を家印として用いた例もあって，厳密に個人印と家印を峻別することは困難である。一方，私印に刻する文字は，名前か名前の一部，それに「印」等の文字を入れて刻するのが一般的である。しかし，平安時代中期になると，中には自分の気に入った吉祥句や成語などを選んで刻し，それを使うことで特定の個人や家などを差す例も存在している。そのような私印をここでは，「遊印」と呼んだ。こうした一般的な印の使い方以外に，信仰に用いるものもある。９世紀頃から印を一種の呪物として土中に埋めることがあったようである。この方向が進んで，平安時代後期以降になり，印鑰社とか，仏像の手に印章を持ったりするのが現われてくるようである。使われ方は異なっているが，こういった印を信仰に用いる例は，３世紀頃の中国にもあったようで，民間道教的祭祀の中に見ることができる。日本の古代に見える信仰に用いられた印は，こうした中国の民間の祭祀が間接的に影響を与えた可能性が存在するようである。There are a considerable number of seals and seal marks of old times used in Japan including existing seals and they are largely classified into the three types, that is, government seals (官印), private seals (私印) and seals of shrines and temples. Government seals consist of official seals used according to laws and regulations and other seals while private seals are divided into family seals and personal seals. However, the way of putting a seal is identical for both official documents and private documents―the seal was impressed on the entire surface where letters are written. In the era of Jogan, private seals that had been formerly used only in private documents were put on the documents presented to officials either.According to the existing old documents, seals of shrines and temples were used officially in many cases, but the manner to use private seals varied considerably. Especially among the nobility who were able to have public houses, it is not easy to discriminate family seals from private seals. There are examples where a seal bearing a personal name was used as a family seal.Meanwhile, the letters engraved on private seals generally bore the personal name or part of the name to which a letter such as “seal” was added. However, in the middle of Heian era, there were some examples where favorite lucky phrases or idioms were selected as engraved inscriptions which served to identify particular persons and families. This kind of private seal was called “Yu-in” (遊印). In addition to the seals used generally in this way, some were used for religious purposes. From around the 9th century, it appears that there was a custom that seals were buried as a fetish in the ground. This custom progressed so that in and after the last half Heian era, In\u27yakusha shrines (印鑰社) and images of Buddah with a seal in hand came into existence. Although used in different ways, the presence of the example to use such seals on religious occasions seems to have been seen around the 3rd century also in China, just as done by the public in religious rites of Taoism. It is possible that the seals used in religious rites in old times in Japan were indirectly influenced by public religious rites in China