Taika Reform

The Taika Reform is the name historians give to a series of political changes in Japan that began with a coup in 645. The word Taika (大化) means “great change” and was the name of the new era proclaimed that year — the first time Japan used era names in the Chinese way. The reforms aimed to replace a system in which great clans held their own land and people with a system in which a single ruler, the tennō (emperor), governed through officials, laws and registers.

Most of what we know comes from the Nihon Shoki (Chronicles of Japan), the court history completed in 720 under Prince Toneri, a son of Emperor Tenmu, with other court compilers. It describes the coup in dramatic detail and quotes a long Reform Edict said to have been issued at the start of 646. Because the Chronicles present seventh-century events from the perspective of a court seventy years later, historians have spent a century testing their account against other evidence, especially wooden tablets and the remains of palaces.

The reform did not create a new state overnight. It was the start of a long process that continued through the reigns of Tenji (668–671) and Tenmu (673–686), through the Asuka Kiyomihara code of 689 and the Taihō Code of 701. But the events of 645 became the traditional starting point of the Japanese imperial state.

In the sixth and early seventh centuries, the Yamato king ruled together with powerful clans (uji). Each clan had hereditary titles, its own lands and groups of dependent workers (be) who produced goods or services for it. The greatest of these clans in the early seventh century was the Soga. Soga leaders had married their daughters into the royal family, championed Buddhism, built Asuka-dera, and dominated the choice of rulers.

Under Empress Suiko (r. 593–628), Soga no Umako shared power with Prince Shōtoku. Under Umako’s son Emishi and grandson Iruka, the Soga main family remained dominant, but opposition from other clans and divisions within the Soga weakened its political leadership. In 643 Iruka attacked Prince Yamashiro no Ōe, Shōtoku’s son and a possible heir to the throne, at Ikaruga; Yamashiro and his family died. According to the Chronicles, the Soga were also building grand tombs and residences in a style that looked like royal privilege.

At the same time, students who had gone to China with the embassies of Shōtoku’s time were coming home. They had watched the Sui dynasty fall and the Tang rise, and they knew how a Chinese-style state worked: a graded hierarchy of officials, household registers, taxes and labour service assessed chiefly on registered adult men, and rules for allotting land. For ambitious young royals, these ideas offered a way to break the Soga.

The conspiracy was led by Prince Naka no Ōe, a son of Empress Kōgyoku, and Nakatomi no Kamatari, a member of a clan of court ritualists. The Chronicles tell a famous story of how they met: at a game of kemari (kickball) at Asuka-dera, the prince’s shoe flew off, and Kamatari picked it up and returned it, beginning their friendship.

On the twelfth day of the sixth month of 645 in the calendar used by the Nihon Shoki, a ceremony was held at the Asuka Itabuki Palace in front of the empress in which, according to the Chronicles, a memorial from the “three Korean kingdoms” was being read aloud. The swordsmen Saeki no Komaro and Waka-inukai no Amita had been chosen to strike, with Kamatari and his men standing by with bows; when they hesitated, Naka no Ōe himself attacked Iruka, and the two swordsmen killed him. The next day Soga no Emishi, besieged at his residence, died. According to the Chronicles, Emishi and his people burned the court histories compiled under Shōtoku and Umako (the Tennōki and Kokki); the Kokki is said to have been snatched from the fire and handed to Naka no Ōe.

Empress Kōgyoku abdicated — the first recorded abdication in Japan. Her brother became Emperor Kōtoku, and Naka no Ōe became crown prince. New ministers were appointed, Kamatari became the chief adviser (uchi no omi), and Takamuko no Kuromaro and the monk Min were named national scholars. Later in 645 the court moved to Naniwa, on Osaka Bay, the gateway to the sea routes to Korea and China.

The Nihon Shoki dates the Reform Edict to the first day of the first month of 646 in the lunisolar calendar. It has four main articles. The first ordered the abolition of specified royal and clan holdings of land and dependent workers; in return, high officials were to receive allowances in the form of the produce of a number of households. It has traditionally been read as establishing “public land and people”, but scholars dispute whether it proclaimed comprehensive nationalisation and how far it was carried out. The second set up a capital region and a system of provinces and districts, with officials, checkpoints, post horses and relay stations; district heads were to be chosen from the existing local chiefs (kuni no miyatsuko). The third ordered household registers and tax registers to be made, and a system for allotting rice land. The fourth abolished the old levies and introduced new, uniform taxes on rice fields and households, paid in silk, cloth and other goods, along with contributions of horses, weapons, labourers and palace servants.

In the same period other edicts regulated burials — the so-called Hakusō-rei, which limited the size of tombs according to rank — sent new officials to the eastern provinces to count people and weapons, and changed the rank system.

The ideas behind the edict came from China. Tang institutions included household registration, the equal-field system and the zu–yong–diao system of taxes and labour, whose principal obligations fell on registered adult men, together with a hierarchy of provinces and counties run by appointed officials. Japan’s later system of handen shūju (periodic allotment of rice fields) and the taxes known as so, yō and chō were modelled on these institutions, though with differences: under the later ritsuryō rules, rice-land shares were calculated for registered males and females aged six and over, including children and elderly people, not only for tax-paying adult men; shares varied by sex and status and were allotted through households. An influential view dates the system’s legal establishment to the Asuka Kiyomihara code of 689.

The move to Naniwa was more than a change of address. Naniwa was the port through which envoys, monks and goods came and went, and a new palace there — the Naniwa Nagara-Toyosaki Palace, completed in 652 — gave the reform government a stage. Its scale and plan made the ambitions of the new government visible.

Excavations in central Osaka, begun in 1954 under Yamane Tokutarō, found two superimposed palaces. The earlier one shows traces of fire and is identified with the palace that burned in 686; its construction is attributed to Emperor Kōtoku after the reform. It was very large for its time, with a spacious court and halls, including octagonal buildings, laid out on a Chinese-style plan. For many historians, the sheer scale of this palace suggests that the government of the 650s really did have ambitions to rule through a large bureaucracy.

The unity of the reformers did not last. In 653 Naka no Ōe returned to Asuka with most of the court, leaving Kōtoku at Naniwa, where he died in 654. Kōgyoku returned to the throne as Empress Saimei, and Naka no Ōe continued to hold real power.

The coup of 645 happened in the middle of an East Asian crisis. In 642 the general Yeon Gaesomun seized power in Goguryeo in a bloody coup, killing the king and many nobles; in the same year Baekje captured Silla’s western fortresses, and Silla’s Kim Chunchu went to Goguryeo in search of help and was detained. In 645, the very year of the Japanese coup, Emperor Taizong of Tang invaded Goguryeo; his army was stopped at the siege of Ansi fortress and had to withdraw. The responses of the region’s states differed: Goguryeo resisted Tang invasion, Silla sought Tang support against its rivals, and Yamato later supported Baekje’s restoration. Tang expansion forms part of the context in which historians interpret Japan’s centralisation.

Korean diplomacy reached Japan directly. In 647, according to the Nihon Shoki, Kim Chunchu himself came to Yamato as an envoy; the next year he went to the Tang court and secured an alliance against Baekje. That alliance destroyed Baekje in 660. Japan sent a large army to help restore Baekje, but it was crushed by the Tang and Silla at the Battle of Baekgang in 663. The defeat pushed the Yamato court to build fortresses in western Japan, welcome Baekje refugees — many of them officials and scholars — and speed up the building of a centralised state.

Tang China mattered to the reformers as both a threat and a model. Its government used household registers, appointed officials and tax systems that Japanese students and monks had studied during their years abroad. As Tang armies campaigned in Korea, the Yamato court drew on these institutions to strengthen its own government and prepare for diplomacy and war.

After Baekgang, Naka no Ōe moved the capital to Ōmi, by Lake Biwa, in 667 and was formally enthroned as Emperor Tenji in 668. In 669 Kamatari, on his deathbed, received the new surname Fujiwara; his descendants would dominate the court for centuries. In 670 the first nationwide household register (the Kōgo-nen-jaku) was compiled — a key step towards the census the Reform Edict had promised.

After Tenji’s death, the Jinshin War of 672 brought his brother to the throne as Emperor Tenmu, who strengthened the central government further. The Asuka Kiyomihara administrative code was issued in 689, a large grid-plan capital was built at Fujiwara (694), and in 701 the Taihō Code further consolidated penal and administrative law. These were stages in a long institutional development rather than the simultaneous completion of every measure announced in 646.

For this reason many historians describe the Taika Reform less as a single event than as the opening phase of half a century of state-building, driven both by internal rivalry and by the shock of war with Tang and Silla.

The text of the Reform Edict in the Nihon Shoki uses terms that match the Taihō Code of 701 very closely. This raised a suspicion: had the compilers of 720 rewritten the edict in the language of their own laws? The most famous test case was the word for “district”. The district unit, read kōri, is written 郡 in the Chronicles, the spelling of the Taihō Code. If the reform government had really used this character in 646, documents from the late seventh century should show it.

This question, the gunpyō debate (gunpyō ronsō, the “郡 versus 評” debate), divided historians from the 1950s, after Inoue Mitsusada opened it in 1951. Sakamoto Tarō defended the essential authenticity of the edict, while Inoue argued that its text had been heavily revised. The answer came from archaeology: in 1967, wooden tablets from the Fujiwara palace site, including one dated to the year 699, wrote the district unit with a different character, 評 (also read kōri; hyō is its Sino-Japanese reading). This showed that before 701 the district was written 評, and that the Nihon Shoki’s text of the edict had been at least partly rewritten in later terms.

From the late 1960s some scholars, notably Kadowaki Teiji and Hara Hidesaburō, went further and doubted that there had been any major reform in 645–646 at all, treating the “Taika Reform” as largely a creation of the compilers. Later finds have added evidence about seventh-century administration. A tablet dated to the year 648 was found in 1999 in a valley north-west of the early Naniwa palace, and a tablet dated 665 from the Ishigami site in Asuka records a hierarchy of province, district (評) and fifty-household unit. These finds, together with the scale of the early Naniwa palace, show real state-building in the mid-seventh century, but they do not by themselves establish which provisions of the surviving edict existed or were carried out in 646. Japanese reference works still describe several competing positions, from basic acceptance of the Chronicles’ account to outright denial, and the scale and chronology of the reforms remain debated.

Japanese interpretations of the reform have changed with Japan’s own politics. Since the Meiji Restoration (1868) the Taika Reform has often been praised as a forerunner of the “restoration of imperial rule” and as the starting point of the centralised imperial state. Even before 1945 the historian Tsuda Sōkichi suspected that the edict had been embellished by later compilers, and after the war new evidence such as wooden tablets carried this criticism further, until some scholars questioned whether the reform had happened at all. The Korean historian Song Wan-beom (2019) argues that the image of the Taika Reform as an ancient “restoration” was itself shaped by modern Japan.

Another line of interpretation emphasises the international setting. Historians such as Bruce Batten (1986) have linked the building of the ritsuryō state to the sense of foreign threat after Tang expansion and the defeat of 663, and Song Wan-beom (2009) interprets Kim Chunchu’s multilateral diplomacy in relation to the series of coups across East Asia in the 640s. A comparative account must still look at each state’s particular alliances and conflicts: Silla strengthened its monarchy with Tang backing, while Yamato later supported Baekje’s restoration. After 663 many Baekje refugees, including officials and scholars, entered Japanese service.

The reforms drew on Chinese legal and administrative practice within a longer history of exchange in East Asia, often through the Korean kingdoms. Buddhism and Chinese writing had reached the Japanese archipelago long before the Tang dynasty, so their spread should not be presented as a result of the Taika Reform. Japan also borrowed selectively: it kept hereditary court families at the top and combined Chinese-style law with native kami ritual.

A fair summary is that the Taika Reform was both a court coup in a clan struggle and part of a region-wide transformation. The surviving edict contains later revisions, so the Nihon Shoki’s narrative and terminology require critical examination. Archaeology provides independent evidence of seventh-century state-building, while the relationship between these developments and the edict preserved in the Nihon Shoki remains debated.

The Nihon Shoki is the principal continuous narrative for these events. Prince Toneri, a son of Tenmu, headed its compilation, which was completed in 720, and officials such as Ki no Kiyohito did much of the practical work. Its institutional and political setting — a court descended from the victors of the 640s and 670s — calls for critical reading, but the precise motives behind individual passages should not be assumed without evidence.

Independent checks come from outside the Chronicles. Wooden tablets (mokkan), used as labels for tax goods and as official notes, preserve the actual vocabulary of administration year by year. Palace excavations at Naniwa and Asuka show the scale of building. Chinese histories of the Tang record Japanese embassies of the 650s and give an outside view. Korean sources, especially the Samguk sagi, provide the peninsular side of events such as Kim Chunchu’s travels and the fall of Baekje.

Reading these together is the method modern historians use: not accepting the Chronicles wholesale, not rejecting them wholesale, but testing each claim against material that the compilers could not edit.