『日本紀略』後篇の史料的構造と『新国史』の編纂過程について : 天文異変・地震記事による『紀略』後篇の検討

抄録

We usually believe the articles of the latter part of "Nihonkiryaku" 日本紀略 (Abbreviated History of Japan) but cannot do so completely. Also, we do not know its editor or purpose. Such material facts would be very benefical when using this document, and we will be able to make conjecture about the editor. We also have "Shinkokushi"新国史 (Neo-National History), the sourcebook of the latter part of "Nihonkiryaku." The ancient and medieval Japanese aristocracy was very interested in astronomical anomaly, so there are many related articles in "Nihonkiryaku, " it does not cover all of the important anomaly that occured. Because information was secret and sources of articles limited, we can know the peculiarities of sources of the latter part of "Nihonkiryaku" from articles of astronomical anomaly and earthquakes, which had similar significance. The results of the present author's examination are (1) "Shinkokushi" was nearly completed as early as the Shoutai 昌泰 era (898〜901). (2) The "Shinkokushi" which the editor of the "Nihonkiryaku" used has serious omissions for the Kampyou 寛平 era (889〜898). He entered articles in large numbers, for example from copies of tenmonmissou 天文密奏, secret reports about astronomical anomaly and earthquakes for the Emperor. (3) He used a comparatively complete gekinikki 外記日記 (diary of the geki). However, the editor was not geki, the secretary of the prime minister's office. (4) The editor was not In院 (an associate Emperor) or of the Sekkanke 摂関家 (regent's house). (5) In spite of using many copies of tenmonmissou, the editor was not a member of an astrologer's family. Rather the editor, in the opinion of the present author, was a member of Ooe-Clan 大江氏, which a close relationship to the "Shinkokushi" and historical literature. Especially, Ooe no Masafusa 大江匡房 probably participated in the edition of much circumstancial evidence. (6) The editing of the "Shinkokushi" began to give historical legitimacy for the Uda宇多 lineage's heredity to the Emperor's position, and the more concrete its right became, the lesser need for completing this book. (7) The main reason for the stagnation the editing was that the editor could not explain the trouble over relegation of Sugawara no Michizane 菅原道真. (8) The author found that rekidou 暦道 (masters of the almanac) had been forecasting solar eclipses rigidly according to the Semmyoureki 宣明暦 almanac during the first half of the 10th century, and then revising from the latter half. Forecasting by rekidou became more correct with this revision. This is an important discovery for the history of Japanese astronomy.