古代郡印論（Ⅳ. 論考 / 2. 古代印論 : 出土・伝世印と印影）

公印のうち，郡印は令文に規定がないものの，その印の規格は印影・出土印・伝世印を通じて，平均方１寸５分程度（約4.5cm）であり，国印（方２寸，約６cm）と郷印（方１寸，約３cm）の中間の大きさといってよい。しかも年代の明確な文書に押された郡印の印影に基づいて編年的に並べてみると，天平20年（748）の山背国宇治郡印が篆書体であり，天平勝宝から天平宝字年間（757～765）にかけて楷書体（天平神護２年〈766〉の「足羽郡印」楷書体例あり），その後はすべて篆書体を呈している。この時期は国印の改鋳時期でもあるが，国印の改鋳は書体の変更にまでは及んでいない。郡印の篆書体から楷書体への変化は，次のように説明できるであろう。そもそも篆書体は，中国の秦代に始皇帝によって“皇帝の書”と位置づけられ，臣下の用いる隷書体と区別されたものである。天平勝宝～天平宝字年間は，藤原朝臣仲麻呂（恵美押勝）が絶大な権力を握り，中国にならった諸改革を実施したのは周知のとおりである。仲麻呂の印に対する執着の強さは，印影を伝える藤原氏の家印が，他の私印では例をみない公印並みの典型的な篆書体であり，また自ら恵美家印を公印と認めさせたりした施策などからも明らかである。仲麻呂が，皇帝の書体である篆書体は専ら八省印や国印（クニノミコトモチとしての国司の使用印）に用いるものとし，一方郡印は中国で臣下の用いる隷書体から発展した楷書体に限定し，地方社会において国印と明確に識別させた施策であると推測できる。仲麻呂政権の崩壊とともに，宝亀５年（774）以降の郡印が再び篆書体に戻る傾向は，この推測を裏付けているであろう。これらの印影に基づく郡印の編年に，これまで年代不明とされた出土・伝世の郡印をあてはめた時に，はじめて妥当な年代を与えることができることも証明した。これらの作業は，印影・出土印・伝世印を総合的に検討するとした“日本古代印集成”の研究目的にかなうものであるといえる。The particulars of the County Seals（郡印）, among official seals, were not stipulated in any government rule, but the length of their sides was about 4.5cm in average, an intermediate size between the side length of about 6cm of the Province Seal（国印）and the side length of about 3cm of the Village Seal（郷印）, regardless of the types of measured items, that is, seal marks, excavated seals or, inherited, handed down through generations seals. When the County Seals impressed on the documents having definite dates are identified according to a chronological sequence, it has been confirmed that the Uji County Seal of Yamashiro Province used in the 20th year of Tempyō（A.D.748） was of a Tensho style（篆書）, a Kaisho style（楷書）was adopted from Tempyōshōhō era to Tempyōhōji era（A.D.749～765）, and all seals had the Tensho style thereafter. This period is the time when the government seals were recast, but the recasting of the Province Seals did not involve any change in the character style. The change in the use of the Kaisho style instead of the Tensho style can be explained as stated below. The Tensho style was originally determined as the“character style of the Emperor” by Shih-Huang-Ti of Ch\u27in Dynasty of China, and was distinguished from the、Reisho style（隷書）used by subjects. It is well known that duringthe era from Tempyōshōhō to Tempyōhōji, Fujiwara-no-Nakamaro（Emi-no-Oshikatsu) had extraordinarily powerful rights, enforcing various innovations by following the precedentsof China. The intensity of Nakamaro\u27s persistence in his seals was evident because the family seal of Fujiwaras had a typical Tensho style which is quite unusual compared with any other private seal, and he issued a policy to have the seal of Emi family accepted as an official seal. Nakamaro decided that the Tensho style as a style peculiar to an Emperor should be exclusively used as Seals of Eight Ministries（八省印）or a Province Seal. On the other hand, the County Seal was limited to have only a Kaisho style which was developed from the Reisho style used by the subjects in China. The policy was assumed to have been taken to clearly discriminate a County Seal from a Province Seal in local communities. This assumption will be attested by the fact that along with the collapse of the government of Nakamaro, the County Seal created after the 5th year ofHōki（A.D.774） took a Tensho style again. It was also proved that when the year of creation of a County Seal was determined based on these seal marks, a reasonable year can be given only after excavated and inherited County Seals whose eras were unknown to date are referred to. Only these kinds of work can satisfythe purposes of study for “Nippon Kodai-in Shūsei”（『日本古代印集成』）which was intended to make an overall evaluation of seal marks, excavated seals and inherited seals