<論説>『日本書紀』編修論序説

Abstract

本稿は、『日本書紀』欽明二年(五四一) 三月条の帝王本紀にまつわる分注を主たる切り口として、『日本書紀』の編修に係わる実態の一斑、および『日本書紀』の編纂開始の時期について解明することを試みたものである。欽明二年三月条の分注は、複数の皇子女系譜に関し、編者がいずれが妥当か判断がつかない場合、それらを本文・分注に掲げるにおよんだことを指し示したものとなる。そうした『日本書紀』の凡例の一つに相当するような記述が、巻第一九にいたってはじめて取り上げられたのは、採用した異説が同書のなかでもっとも多かったがゆえと判断される。また、編者は、複数の皇子女系譜などの掲載にあたっては、正しい可能性がより強いものをできるだけ本文として呈示するよう努めたことがおさえられる。『日本書紀』の編纂時期をめぐっては、天武朝から長期にわたって断続的に実施されたとするのが通説的な理解となる。けれども、本稿における考察の結果、その編修は、大宝令制下において開始されるにいたったことが明らかになったといえる。

The study of the compilation of the Nihon shoki (Chronicles of Japan) has been carried on for centuries. In recent times attempts at clarifying the issue have been conducted in various disciplines and have not been restricted to history. Nevertheless, there are no primary sources that provide concrete accounts of the process, and one can detect a tendency to slip haphazardly into arbitrary interpretations. As a result, the only remaining method is to take an internal approach, making a comparative analysis of events described in the work in order to clarify the issue. Grounded firmly on this understanding, this article begins with the annotation to the entry for the third month of Kinmei 2 (541) in the main account of the imperial biography with the aim of elucidating an aspect of the historical facts concerning the compilation of the Nihon shoki and also the dating of the start of the compilation process of the Nihon shoki. The annotations for the third month of Kinmei 2 indicate that when confronted with the problem of determining the legitimacy of multiple lineages of imperial offspring, the compilers of the Nihon shoki adopted the policy of noting them in the main section and accompanying annotations. However, the problem is that these passages that correspond to an explanatory note, or legend, for the Nihon shoki inexplicably first appear in the 19th fascicle. When looking through the Nihon shoki, one can see multiple lineages of imperial offspring are taken up prior to the 19th fascicle. Thus it would seem appropriate for those explanatory passages to have been appended to the places were the multiple imperial lineages were first addressed. Then, in considering why this sort of annotation was attached to the record of Kinmei's reign, it can be surmised that it was because these variant opinions that were incorporated in this work were the most numerous. Presumably, the compilers of the Nihon shoki, having the opportunity to create a fascicle devoted to lineages, must have grasped the fact that a lineage of the offspring of Kinmei would have been the most numerous. That being the case, it can be surmised that it is reason the passages that are equivalent of explanatory notes of the Nikon shoki were included in the 19th fascicle. In addition, one can deduce the fact that the compilers of the Nihon shoki strove as much as possible to include only the lineage with the strongest possibility of being correct in the main section (although there were some exceptions) when including multiple lineages of imperial offspring. Finally, regarding the period of the compilation of the Nihon shoki, it can be said that the general understanding has been that it was carried out intermittently over a lengthy period from the reign of Emperor Shomu to that of Shogen. However, the multiple lineages of imperial offspring in the entry for the second month, tsuchinoe-tora, of Tenchi 7 (668) of the Nihon shoki, cannot be neglected as long as one pursues this problem. Judging from the form of these lineages, it is possible to discern that there arose confusion among the compilers of the Nihon shoki regarding whether Prince Takeru should be included. Nevertheless, in regard to the problem of Prince Takeru, it could have easily been solved by consulting his elder sister Jito. Ultimately, it can be made clear that the 27th fascicle, which includes the lineage concerned with Takeru, was edited after the death of Jito in the 12th month of Taiho 2 (702). In addition, concerning two records from the close of the 7th century that have heretofore been thought to be related to the compilation of the Nihon shoki, it would be more prudent to consider them separately to understand the problem. As a result, weighing these factors in terms of the compilation of the Nihon shoki, the work should probably be judged as having been begun under rubric of the Taiho legal system.