The Nihon Shoki日本書紀 is Japan's second oldest extant chronicle, and the first of its Six National Histories 六国史, which contain most of what is known about Japan down before 887 CE.
The Nihon Shoki was submitted to the Imperial court in 720 CE, only eight years after the Kojiki. Both ancient chronicles were written in compliance with commands handed down by reigning Empresses and were intended, above all, to sanctify and strengthen Japan's Imperial rule. The first chapters of both were focused on myths about the birth and descendants of The Great Goddess Amaterasu, the ancestress of Japan's long line of Emperors and Empresses. The last books of both were limited largely to what was done and said by human descendants of the Great Goddess. Thus the two chronicles are commonly bracketed together.
But when modern Japanese scholars selected texts for inclusion in Iwanami's famous compendia, the Kojiki was made Volume 1 in the series entitled Nihon ShisŁETaikei (日本思想体系) and the Nihon Shoki became Volumes 67 and 68 of the Nihon Koten Bungaku Taikei (日本古典文学大系). The Kojiki was thereby classified as "Japanese thought", along with the writings of such distinguished religious figures as Shōtoku Taishi (574-622), Kūkai (774-835), and Nichiren (1222-82). The Nihon Shoki, on the other hand, was designated a "Japanese classic" and published in a series that includes nearly all historical texts inserted in this Japanese Historical Text Initiative. So the first of Japan's two oldest chronicles has become classified as religious and the second as historical.
This classification should not blind us, however, to the commonality of the two. Both were compiled by officials at the Imperial court in compliance with commands handed down by current occupants of the throne. And as deduced from orders issued by Emperor Temmu in the year 682, and discussed in the Introduction to the Kojiki, the compilers of both chronicles were required to use the same kinds of sources: Imperial Records (Teiki 帝紀) and Ancient Myths (Kuji 旧辞)the latter were also referred to as Myths of Origin (Honji 本辞). The compilers of both chronicles were apparently told that Imperial wish was for chronicles that would sanctify and strengthen Imperial rule.1
Over 60 years before Emperor Temmu handed down his command, Prince Shōtoku also ordered that Japan's oral traditions (記) be recorded. We know this because of an entry in the Nihon Shoki for the year 620. After studying the Japanese original and the Aston translation, I come up with this tentative re-translation:
"During this year  Prince Shōtoku, in concert with Shima no Omi, had the following oral traditions (記) recorded: Imperial Traditions (天皇記) and State Traditions (国記), as well as Traditions of Origin (本記) for Omi (臣) and Muraji (連), Tomo no Miyakko (伴造), Kuni no Miyakko (国造), the 180 Be (部), commoners (井公民), et al.2
Here we find that Prince Shōtoku was having a written record made of "oral tradition" about the Kami-origins of Japan's major group-heads, beginning with the Empress herself and moving down the political ladder to [the heads of ] commoner groups (井公民) at the bottom. By adding the word 等 (et al), the Prince was saying that other group-heads might be added. At this early time in the building of a Chinese-like empire in Japan, the most powerful person at the Imperial Court was making sure that the "oral traditions" (Kami-myths) of all major group-heads (political figures) would be recorded.
Prince Shōtoku's reasons for having these records made were not spelled out by him in the Temmu manner. But from what we know about the political situation at the time, and in the light of what was later commanded and done, one dares to hypothesize that Prince Shōtoku, like later Emperors and Empresses, had two interrelated objectives: first, to direct the power of belief in Kami-myths (ancestor worship) to the sanctification of Empress Suiko's sovereignty; and second, to increase the likelihood that Empress Suiko would be succeeded by a Prince-Shōtoku son. Since Suiko was not succeeded by a Shōtoku son, clan chieftains that supported the candidacy of the prince who was enthroned as Emperor Jomei in 629 undoubtedly objected to Shōtoku's Kami-myth chronicle, and had it destroyed.
What Emperor Temmu and Prince Shōtoku did and said about recording ancient myths suggest that both the Kojiki and the Nihon Shoki were produced for similar reasons. But they were also quite different. The scholarly editors of the Iwanami compendia were right to include the Kojiki in a collection of works written by religious leaders, and the Nihon Shoki in a collection of historical texts.
The Kojiki's greater religiosity is clearly revealed in its first book on the origin and Heavenly development of Japan's Imperial descent line. Even its last two books are focused almost exclusively on Imperial ancestors, Imperial descendants, and Imperial relatives. The long and important reign of Empress Suiko (592-628), for example, is covered in two short paragraphs, and not one word is written about later reigns of the seventh century. By contrast the Nihon Shoki, covering almost the same span of time and beginning with chapters on the origin of the Imperial descent-line in the Kami Age, starts off by inserting different versions of Kami-myths about The Great Goddess. We are not told which is true and which is false, leaving the impression that all were true. Moving on to the reigns of living Emperors and Empress, the Nihon Shoki supplies considerable historical detail about non-Kami affairs--Aston's translation of the Suiko chapter is, for example, 35 pages long. The later chronicle contains very valuable information about the later reigns of Emperor Temmu (672-686) and Empress Jitō(686-697), during which most of the Great Reforms were vigorously initiated.
The Nihon Shoki's dating of events in sometimes wrong, especially for Japan's earliest reigns. But archaeological evidence, as well as comparisons with contemporary records of Korea and China, shows this ancient chronicle to be a remarkably authentic record of long stretches of Japan's ancient past.
But the Chinese character of the Nihon Shoki should not be overlooked. This chronicle's non-Japanese proclivities were noticed and deplored by Japan's National Learning (Kokugaku 国学) scholars of the eighteenth and nineteenth centuries. Motoori Norinaga (1730-1801) and Hirata Atsutane (1776-1843), leading figures in the movement, found the strongest and most convincing evidence of pure Japanese culture in the Kojiki, not in the Nihon Shoki. Why did this later chronicle, written only eight years later, have such a strong non-Japanese (Chinese) flavor?
The first point to make is that the author of the Nihon Shoki, undoubtedly an official at the Imperial court, was obviously more deeply immersed in Chinese learning than Yasumaro, the Kojiki author. For whatever reason, the Nihon Shoki provides more details about Japan's China-oriented Great Reforms.
Each of these two ancient chronicles was therefore linked with a different but mutually-supportive thrust of the Great Reforms. While the Kojiki is the sacred text of a new religious movement called Imperial Shinto 呈神道, the Nihon Shoki is a remarkably reliable historical record of the rise of Japan's new Ritsuryō 律令 order. Each of these reform thrusts was administered by a different branch of the new Imperial government. To the right and directly under the reigning Emperor or Empress stood the Council of Kami Affairs (Jingikan 神祇官) which created, funded, administered, and controlled Imperial Shinto. To the left and also directly under the reigning Emperor or Empress was the Council of State (Dajōkan 太政官) which headed the new bureaucratic system. So the Kojiki is more like a sacred text of Imperial Shinto, and the Nihon Shoki more like an official record of the emerging Ritsuryō order.
Although deeply colored by Chinese ideas and tastes, the Nihon Shoki was still firmly grounded in Shinto (Kami belief and worship). Like the Kojiki it affirmed the sanctity of the Imperial line of descent from the Great Goddess Amaterasu. And like the Kojiki it actively supported Japan's two-pronged Great Reforms for increasing the authority and power of Japanese sovereignty. Significantly, the amazing results of these Great Reforms (including the Imperial Shinto movement) came at a time of constant fear, at the Imperial court, of rebellion at home and invasion from China.
But while the Kojiki was aimed primarily at sanctifying Imperial authority (a religious function), the Nihon Shoki was aimed primarily at increasing the power of Imperial control (a political goal). Together they were underscoring an old and overriding policy that was articulated in recent times as The Unity of Religion and Politics (Saisei icchi 祭政一致).
August 22, 2006
1 To see this Temmu command, search the Preface of the Kojiki for a keyword in his command.
2 To see the Japanese original or the Aston translation, search the Nihon Shoki for a keyword in this command.