Japanese History Digest

Asuka period

Asuka period

The Asuka Period refers to the era from 592 to 710, during which the imperial capital was located in Asuka.

 

The Reign of Empress Suiko (592-628)

The reign of Empress Suiko (592-628) marked the enthronement of the first female emperor in Japanese history. Together with Prince Shotoku (Umayado no Prince) and Soga no Umako, the reign of Empress Suiko saw the development of the national system, the promotion of Buddhism, and the strengthening of foreign relations. After Emperor Sushun was assassinated by Soga no Umako, Empress Suiko ascended to the throne and reportedly entrusted Prince Shotoku with national affairs as crown prince. However, it is believed that the trio of Empress Suiko, Prince Shotoku, and Soga no Umako actually held central roles in the government.

The debate over whether to worship Buddhism was resolved with the assassination of Mononobe no Moriya by Soga no Umako in 587, laying the foundation for the acceptance of Buddhism as a new religion linked to royal authority. During the reign of Empress Suiko, the "Nihon Shoki" records that in 594, Empress Suiko issued the "Imperial Rescript on the Promotion of the Three Treasures," clarifying a policy of national protection and promotion of Buddhism through the construction of temples and the training of monks and nuns. Soga no Umako led the construction of Asukadera (Hōkō-ji), and Buddhist temples were also valued as symbols of royal prestige.

In terms of domestic affairs, the Twelve Ranks of Captivity system was established in 603, and the Seventeen-Article Constitution was reportedly enacted in 604. While these were aimed at the upper class of powerful clans within the framework of the clan and surname system, they also promoted the idea of ​​valuing individual talent and hard work rather than just family background, and by outlining the code of conduct for officials and principles of governance, they are understood to have outlined a vision for a new governing order centered on the emperor. These are seen as early stages of a shift from clan-centered rule to a centralized national system centered on the emperor.

In terms of foreign relations, the reign of Empress Suiko saw changes in the situation in East Asia after the Sui Dynasty unified mainland China, and the reign of Emperor Suiko actively sought to adopt its advanced systems and culture. The first Japanese envoys were sent to Sui in 600, and in 607 Ono no Imoko was sent to Sui again, delivering a famous sovereign letter to Emperor Yang of Sui. Furthermore, in 608 Pei Shiqing visited Japan, further increasing exchanges between the two countries. Thus, the reign of Empress Suiko was a time when the foundations for the formation of the Japanese nation were laid through the full-scale acceptance of Buddhism, the development of political systems, and the development of diplomacy.

 

During the reign of Emperor Jomei (629-641)

The reign of Emperor Jomei (629-641) began after the death of Empress Suiko (628), following the adjustments made to the imperial succession. Following her death, the most likely successors were Emperor Bidatsu's grandson, Prince Tamura (later Emperor Jomei), and Prince Yamashiro no Oe, the son of Prince Shotoku. Opinions were divided among ministers, but Prince Tamura, who enjoyed strong support from Soga no Emishi, ascended to the throne as the 34th emperor in 629. Sakaibe no Marise, who supported Prince Yamashiro no Oe, was pursued by the Emishi and committed suicide. It is said that this conflict resulted in the establishment of the Jomei government.

The power of the Soga clan grew even stronger during Emperor Jomei's reign, and actual political management appears to have been carried out by powerful clans led by Soga no Emishi. While historical documents do not clearly state the Emperor's own policies, it is certain that real power in running the nation was concentrated in the hands of the Soga clan. Amidst the dramatic upheaval in East Asia following the founding of the Tang Dynasty in 618, Emperor Jomei dispatched Japan's first envoy to Tang China in 630, achieving a diplomatic shift from Sui to Tang. This marked the beginning of full-scale exchanges with the Tang Dynasty thereafter.

As part of his palace and capital policy, from around 639 he ordered the construction of Baekje Palace on the banks of the Baekje River and also promoted the construction of Baekje Grand Temple. The Nihon Shoki reports that there were plans to build a nine-story pagoda at Baekje Grand Temple, which was envisioned as a grand temple to demonstrate the prestige of the royal authority. However, it is recorded that the temple was destroyed by fire shortly after its construction. The relocation of the capital from Tanaka Palace to Baekje Palace is considered to indicate the formation of a new political and religious base during the Jomei era.

Emperor Jomei took Princess Takara (later known as Empress Kogyoku and Empress Saimei) as his Empress, and gave birth to Prince Nakano Oe (later known as Emperor Tenji) and Prince Oama (later known as Emperor Tenmu). In 641, Emperor Jomei passed away at the Baekje Palace, and Princess Takara succeeded him as Empress Kogyoku, continuing the reign to the next generation.

 

During the reign of Emperor Kogyoku (642-645)

After Emperor Jomei's death, Empress Takara ascended to the throne as Empress Kogyoku, and her reign was marked by the tyranny and subsequent collapse of the Soga clan. Because Empress Kogyoku ascended to the throne without a clear male successor, she has traditionally been viewed as a "temporary empress," but recent research has suggested a more independent view of her political role. During her reign, Soga no Emishi was highly regarded as a minister, and his son, Soga no Iruka, actually led national affairs.

In 643, Iruka sought to expand his own power, supporting Prince Otomo no Oe, believed to be the son of Emperor Jomei, as a potential successor, and is said to have attacked and annihilated the family of Prince Yamashiro no Oe, the son of Prince Shotoku. This tyrannical rule drew growing opposition from powerful clans and the imperial family, leading to increased political tensions. In 645 (the fourth year of the reign of Emperor Kogyoku), Prince Nakano Oe and Nakatomi Kamatari killed Iruka at Itabuki Palace in Asuka, sparking the so-called Isshi Incident.

After Iruka's death, Soga no Emishi also committed suicide by setting fire to his own residence, marking the end of the main branch of the Soga clan. This incident marked an end to the Soga clan's tyrannical rule and the transition to a new political system centered on the imperial family. Immediately after the Isshi Incident, Empress Kogyoku abdicated and handed the throne to her younger brother, Prince Karu. Prince Karu ascended to the throne as Emperor Kotoku, marking the beginning of a series of political reforms collectively known as the Taika Reforms.

Empress Kogyoku's abdication, as far as records can be verified, is the first abdication in Japanese history and set a precedent for subsequent imperial abdications. Thus, the reign of Empress Kogyoku was a crucial period marking the peak of the Soga clan's power, its collapse, and the turning point that led to the Taika Reforms.

 

During the reign of Emperor Kotoku (645-654)

The reign of Emperor Kōtoku was a time of political reform aimed at creating a centralized nation. In 645, shortly after the Isshi Incident, Empress Kōgyoku abdicated, and her younger brother, Prince Karu, ascended to the throne as Emperor Kōtoku. Prince Nakano Ōe (later Emperor Tenji) was appointed Crown Prince and worked with Nakatomi Kamatari to implement a new political system.

With Emperor Kōtoku's accession to the throne, the first era name in Japan according to surviving historical documents, "Taika," was adopted. The political reforms that began with this were known as the "Taika Reforms." The "Reform Edict" issued in 646 outlined the idea of ​​a "public land and public citizen system" that would make land and people state-owned, as well as the reorganization of local administrative districts and the establishment of systems for family registration and taxation, and outlined a policy of creating a unified nation centered on the emperor. These reforms laid the foundation for the later establishment of the Ritsuryo state.

The political center was moved from Asuka to Naniwa Nagara Toyosaki Palace (Naniwa Palace), and it is said that the move of the capital to Naniwa was promoted in the mid-7th century. Naniwa Palace was located in a place that allowed easy travel to China and the Korean Peninsula, and also served as a base for diplomacy and trade. In the later years of Emperor Kotoku's reign, Prince Nakano Oe and Retired Empress Kogyoku returned to Asuka, while Emperor Kotoku remained at Naniwa Palace, and his political position is thought to have gradually weakened.

Emperor Kotoku died at Naniwa Palace in 654, and thereafter Retired Empress Kogyoku ascended to the throne again, becoming Empress Saimei. The reign of Emperor Kotoku can be said to be an important period in which Japan's journey as a centralized state began, with the Taika Reforms that began in the wake of the Isshi Incident.

 

During the reign of Emperor Saimei (655-661)

The reign of Empress Saimei (655-661) began with the re-enthronement of Empress Kogyoku, and was marked by her aggressive civil engineering projects and deep involvement in the affairs of the Korean Peninsula. Following the death of Emperor Kōtoku at Naniwa Palace in October 654 (the 5th year of the Hakuchi era), she ascended to the throne again at Asuka Palace (the current site of Asuka Palace, formerly known as the site of Asuka Itabuki Palace). During her reign, she promoted large-scale construction projects across the country, including the construction of Asuka Okamoto Palace and the massive irrigation canal known as the "Culture of Madness."

During this period, the allied forces of Tang and Silla attacked Baekje on the Korean Peninsula, leading to its downfall in 660. Baekje's royal family and surviving retainers sought aid from Wakoku, and Baekje Prince Tosho also stayed in Japan to seek support. In response to the request for Baekje's restoration, Empress Saimei decided to provide military assistance. She moved to Naniwa Palace to mobilize troops and supplies, then traveled to the western provinces and to Asakura Palace in Tsukushi to prepare for the campaign.

However, in 661, just before a full-scale campaign against the Korean Peninsula, Empress Saimei passed away at Asakura Palace. Prince Nakano Oe (later Emperor Tenji) continued to lead the country without ascending to the throne, acting as a shosei (regent) and dispatching an army to the southern part of the Korean Peninsula to rescue Baekje. After Empress Saimei's death, the Battle of Baekgang took place in 663, where the Japanese-Baekje allied forces fought against the Tang-Silla allied forces. Japan suffered a major defeat and lost its influence on the Korean Peninsula.

The reign of Empress Saimei marked a period of major transformation in Japan's diplomatic and military policies, driven by large-scale domestic projects and active involvement in the unrest on the Korean Peninsula. The strengthening of defense systems after the defeat at Hakusukinoe would begin in earnest during the next reign of Emperor Tenji.

 

From Prince Nakanoue to Emperor Tenji(661-672)

Following the death of Empress Saimei (661), Prince Nakano Oe assumed leadership of the nation as a shosei (a position of state without ascending to the throne), and during this period, he devoted all his efforts to reorganizing the nation and strengthening its defenses following the defeat at Baekgang (663). The capital was moved to Otsu in Ōmi in 667, and the following year, in 668, he officially ascended to the throne as Emperor Tenji, aiming to establish a new political system. The move to Otsu is thought to have been intended to distance himself from the former power base of Asuka while taking advantage of the country's geographical location on the west shore of Lake Biwa to establish a defensive system.

In terms of national defense, in the third year of Emperor Tenji's reign (664), immediately following the defeat at the Battle of Baekgang (663), he deployed defenders to Tsushima, Iki, and Tsukushi, and established an early warning network using signal fires. From that year onward, utilizing the expertise of Baekje refugee engineers, the emperor constructed a series of Korean-style mountain castles, including Ono Castle (Fukuoka) and Kii Castle (Saga), and together with Mizuki Castle (Chikushi), created a multi-layered defense network.

In terms of domestic affairs, the first nationwide family register in Japan, the Kogo Nenshi, was created in 670. This led to a reorganization of the clan and surname system, and progress was made in understanding social status and household status, which would serve as the basis for taxation and military service. The so-called "Omi Code" was also enacted, which is said to have systematized administrative and bureaucratic organizations. However, the code itself no longer exists, and its contents can only be inferred from later historical documents. These measures are considered important preparatory steps for the later establishment of a fully-fledged Ritsuryo system.

In 671, Emperor Tenji appointed his own son, Prince Ōtomo, as Grand Minister of State, placing him at the center of politics, rather than his younger brother, Prince Ōama (later Emperor Tenmu). This led to increased tensions over the imperial succession. After the death of Emperor Tenji, the Jinshin War broke out in 672 between Prince Oama and Prince Otomo, and Prince Oama emerged victorious from this civil war and went on to establish a new system as Emperor Tenmu.

 

During the reign of Emperor Tenmu (673-686)

The reign of Emperor Tenmu (673-686) saw Prince Oama, victorious in the Jinshin War, ascend to the throne as Emperor Tenmu, further promoting the formation of a centralized state with the emperor at its apex. Emperor Tenmu defeated Prince Otomo in the Jinshin War of 672 with the support of local clans, and ascended to the throne at Asuka Kiyomihara Palace the following year in 673. This marked the shift of royal authority over Emperor Tenji's succession to Prince Oama.

Emperor Tenmu is interpreted as having broken away from the traditional politics reliant on powerful clans and developed a system of imperial family politics centered on the imperial family. Instead of permanently appointing ministerial positions, he is thought to have reorganized government offices such as those for the legal and military systems and placed them under the direct control of the emperor, overseeing government affairs himself. He appointed members of the imperial family, including Empress Inuno-Sarara (later Empress Jitō), to key positions, and implemented policies that elevated the status of the imperial family over that of clans.

In 684, Emperor Tenmu established the Yakusa-no-kabane(Eight Kabane Surnames), a new class system dividing the prestige of powerful clans into eight ranks to reorganize the clan-surname structure and clarify the social hierarchy. Another notable feature of his reign was his efforts to establish the various institutions that formed the basis of the Ritsuryo system and building the framework for a centralized state. Furthermore, he is said to have initiated the compilation of the Kojiki and Nihon Shoki, considered Japan's oldest historical documents, and sought to justify the emperor-centered order through the compilation of national history that demonstrated the legitimacy of royal authority.

In terms of religion and culture, he provided state protection for Buddhism, laying the foundation for the cultural flourishing that would later be known as Hakuho culture. He ordered the founding of Yakushi-ji Temple (main construction was carried out during the reign of Empress Jitō) and promoted the construction of temples centered on the worship of Yakushi Nyorai. The Buddhist policy of the Tenmu era symbolized the legitimization of the government and the strengthening of the Emperor's power after the Jinshin War, and established the spiritual and cultural foundation for the formation of the Ritsuryo state.

 

During the reign of Emperor Jitou (690-697)

The Reign of Empress Jitō (690–697) was a pivotal period marked by major advances in the consolidation of the ritsuryō state system and the construction of a fully developed capital city. Empress Jitō was the daughter of Emperor Tenji and supported the reign of Emperor Tenmu as his empress consort. After Emperor Tenmu’s death, she initially intended to have the crown prince, Prince Kusakabe, succeed to the throne; however, when Prince Kusakabe died prematurely in 689, she herself ascended the throne the following year, in 690.

Empress Jitō inherited the various institutions established under Emperor Tenmu and worked to solidify the foundations of the ritsuryō state. In 690, she ordered the compilation of the Kōin Nenjakū (household registers of the Kōin year), thereby ensuring a comprehensive nationwide grasp of population and households. These policies were later carried forward into the Taihō Code promulgated in 701 and constituted an important transitional phase in the formation of the Japanese ritsuryō state. Furthermore, Empress Jitō promoted the construction of Fujiwara-kyō, regarded as Japan’s first full-scale capital city built on a grid-based urban plan (jōbō-sei), and successfully transferred the capital there in 694. Fujiwara-kyō was a large capital characterized by a checkerboard-style layout and became a symbol of centralized state governance centered on the emperor. In the cultural sphere, Empress Jitō is also credited with contributing to the development of court poetry culture, as reflected in the Man’yōshū.

In 697, Empress Jitō abdicated in favor of her grandson, Prince Karu (Emperor Monmu). Thereafter, she continued to be involved in state affairs as Daijō Tennō (Retired Empress), while ensuring a peaceful transfer of power. Her reign occupies an extremely important place in ancient Japanese history, particularly for its role in stabilizing the political system and concretely charting the path toward a fully developed ritsuryō state.

 

During the reign of Emperor Mommu (690-697)

The Reign of Emperor Monmu (697–707) was a significant period during which the legal foundations of the ritsuryō state system were firmly established. Emperor Monmu was the grandson of Empress Jitō and the son of Prince Kusakabe. He ascended the throne at a young age, and in the early years of his reign, the retired Empress Jitō acted as his guardian and supported the administration of state affairs. As a result, the policies of the Tenmu–Jitō regime were maintained while governance gradually transitioned to a new generation.

The greatest achievement of this era was the promulgation of the Taihō Code (Taihō ritsuryō) in 701, compiled under the leadership of Prince Osakabe and Fujiwara no Fuhito, among others. As the culmination of legal reforms initiated under the reigns of Emperor Tenmu and Empress Jitō, the Taihō Code was a comprehensive written law code that systematically organized both ritsu (penal law) and ryō (administrative and civil law). Through this code, the bureaucratic structures of central and provincial government, the taxation system, and institutions such as household registration and the system of land allocation (handen shūju) were legally codified, bringing the ritsuryō state system close to completion in legal terms.

During Emperor Monmu’s reign, an embassy was dispatched to Tang China in 702, promoting the active adoption of advanced Tang institutions and culture. At the same time, efforts were made to strengthen control over the provinces, including enhanced governance in southern Kyushu, thereby reinforcing the foundations of regional administration and advancing the integration of the state. Emperor Monmu took Miyako, the daughter of Fujiwara no Fuhito, as a consort, and their son, Prince Obito—later Emperor Shōmu—was born of this union.

In 707, Emperor Monmu died at the young age of around twenty-five, after which his mother, Empress Genmei, ascended the throne and succeeded to the government. The reign of Emperor Monmu can thus be regarded as a watershed period in which the framework of the ritsuryō state was substantively established through the promulgation of the Taihō Code and preparations for its implementation.

 

Timeline of the Asuka period

592	Soga no Umako assassinates Emperor Sushun → Empress Suiko ascends the throne
604	Establishment of the Twelve Cap Ranks (merit-based official appointment system); promulgation of the Seventeen-Article Constitution
607	Ono no Imoko dispatched to Sui China as envoy
608	Students and monks including Takamuko no Kuromaro, Sōmin, and Minabuchi no Shōan travel to Sui China → They remain for extended periods and transmit Sui-end/Tang-early institutions and conditions upon return
645	Taika Reform (led by Prince Naka no Ōe and Nakatomi no Kamatari; establishment of public land and people system)
663	Defeat of Japanese–Baekje forces at Battle of Baekgang (Battle of Baekchon River) (After Empress Saimei's death; during Prince Naka no Ōe's regency) → National defense measures including frontier guards (sakimori), Mizuki fortress, Korean-style mountain castles, beacon fire networks
668	Emperor Tenji ascends throne; capital transferred to Ōmi Ōtsu Palace → Continued strengthening of national defense
670	Compilation of Kōgo Nenjakū (Kōgo year household registers) under Emperor Tenji
672	Jinshin War (Prince Ōama vs. Prince Ōtomo) → Prince Ōama victorious; enhancement of imperial authority
673	Emperor Tenmu ascends throne; establishes base at Asuka Kiyomihara Palace → Development of imperial family rule; promotion of ritsuryō reforms and reorganization of public land/people system
684	Establishment of Eight Kabane Surnames (Yakusa no Kabane) under Emperor Tenmu
690	Compilation of Kōin Nenjakū (Kōin year household registers)
694	Transfer of capital to Fujiwara-kyō (Empress Jitō)
701	Promulgation of Taihō Code (Taihō ritsuryō) under Emperor Monmu

Facilities where you can learn about the Asuka period

Osaka Museum of History
https://www.osakamushis.jp/eng/

Ootsunomiya Nishikori Archaeological Site of Otsu Palace (Otsu City, Shiga Prefecture)
https://www.biwako-visitors.jp/spot/detail/971

Ishibutai Kofun Tomb (Asuka-mura, Takaichi-gun, Nara Prefecture)
https://asukamura.com/sightseeing/499/

Turtle-shaped Stone Object (Asuka-mura, Takaichi-gun, Nara Prefecture)
https://asukamura.com/sightseeing/522/

Experience Asuka (Asuka-mura, Takaichi-gun, Nara Prefecture)
https://asukamura.com/experience/545/

Asuka Historical Museum operated by the Asuka Historical Preservation Foundation (Asuka-mura, Takaichi-gun, Nara Prefecture)
http://www.asukabito.or.jp/

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