Japanese History Digest

Asuka period

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

During the reign of Empress Suiko (593-628)

The reign of Empress Suiko (593-628) marked the beginning of Japan's first female emperor. Together with Prince Shotoku (also known as Prince Umayado) and Soga no Umako, the reign of Empress Suiko saw the development of the national system, the promotion of Buddhism, and the strengthening of international relations. After Emperor Sushun was assassinated by Soga no Umako, Empress Suiko ascended to the throne and is said to have 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 positions in the government.

The debate over whether to revere 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, she issued the "Edict for the Promotion of the Three Treasures" in 594, clarifying a policy of national protection and promotion of Buddhism through the construction of temples and the training of monks and nuns, as recorded in the Nihon Shoki. Soga no Umako led the construction of Asukadera (Hōkō-ji), and Buddhist temples were also valued as symbols of royal prestige.

In domestic affairs, the Twelve Ranks of Captivity system was established in 603, and the Seventeen-Article Constitution was enacted in 604. While these were aimed at the upper class 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 are understood to have outlined 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 foreign relations, the Sui Dynasty unified mainland China, and as the situation in East Asia underwent major changes, the Suiko dynasty sought to adopt its advanced systems and culture. Envoys were sent to the Sui Dynasty in 600 and 607, and in 607 Ono no Imoko was sent in particular and delivered a famous sovereign letter to the Sui Dynasty, demonstrating Japan's independence and an equal diplomatic stance. Thus, the reign of Empress Suiko was a time when the foundations of Japan's nation-state were formed through the full-scale acceptance of Buddhism, the development of political systems, and active international exchange.

During the reign of Emperor Jomei (629-641)

The reign of Emperor Jomei (629-641) began after the end of the imperial succession negotiations following the death of Empress Suiko. After her death, the two 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, with strong support from Soga no Emishi, ascended to the throne as the 34th emperor. Sakaibe no Marise, who supported Prince Yamashiro no Oe, is said to have been killed by the Emishi. 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 it is believed that Soga no Emishi held real political power. Therefore, while the emperor's own policies are not particularly clear from historical documents, national affairs were run by powerful clans, primarily the Soga clan. As the situation in East Asia became increasingly tense with the establishment of the Tang Dynasty, Emperor Jomei dispatched the first Japanese envoy to Tang China in 630, marking the beginning of full-scale exchanges with the Tang Dynasty thereafter.

Also, from around 639, Emperor Jomei ordered the construction of the Baekje Palace and Baekje Grand Temple on the banks of the Baekje River, aiming to demonstrate the majesty of royal authority through a new capital city and large temple. A nine-story pagoda is said to have been built at Baekje Grand Temple, and excavations have suggested the temple complex was enormous in size, but sources such as the Nihon Shoki state that it was destroyed by fire shortly after its construction. The move from Tanaka Palace to Baekje Palace marks the establishment of a new political and religious base during the Jomei Dynasty.

Emperor Jomei took Princess Takara (later known as Empress Kogyoku and Empress Saimei) as his empress, and gave birth to princes who would have a great influence on future generations, such as Prince Nakano Oe (Emperor Tenji) and Prince Oama (Emperor Tenmu). In 641, Emperor Jomei passed away at the Baekje Palace, and Princess Takara succeeded him as Empress Kogyoku.

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.

To strengthen his own power, Soga no Iruka attempted to support Prince Otomo no Oe, the son of Emperor Jomei, and destroyed the family of Prince Yamashiro no Oe, the son of Prince Shotoku. His autocratic behavior drew opposition from various powerful clans and the imperial family, and the political situation became increasingly tense. In 645, the fourth year of the reign of Empress Kogyoku, Prince Nakano Oe and Nakatomi Kamatari killed Soga no Iruka at Itabuki Palace in Asuka, resulting in the so-called Isshi Incident.

After Iruka's death, Soga no Emishi also committed suicide by setting fire to his own residence, and the main branch of the Soga family was destroyed. 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, and this marked the beginning of a series of political reforms collectively known as the Taika Reforms.

Empress Kogyoku's abdication was the first recorded abdication in Japanese history, setting a precedent for subsequent emperors' abdications. Thus, the reign of Empress Kogyoku was an important period marking the peak of the power of the Soga clan, its collapse, and a turning point leading to the Taika Reforms.

During the reign of Emperor Kotoku (645-654)

The reign of Emperor Kōtoku (645–654) marked the first time that Japan adopted an era name and implemented major political reforms aimed at centralizing power. In 645, Empress Kōgyoku abdicated, and her half-brother, Prince Karu, ascended to the throne as Emperor Kōtoku. Prince Nakano Ōe (later Emperor Tenji) was appointed Crown Prince, and together with Nakatomi Kamatari and others, he led the reforms as the central figure in government affairs.

With Emperor Kōtoku's accession to the throne, the first era name verifiable in surviving historical documents, "Taika," was adopted, symbolizing the beginning of a new system. The Taika Reforms, initiated by the Isshi Incident, were enacted in 646 with the "Reform Edict," which set out the principles of a public land and public citizen system, the reorganization of local administrative organizations, the creation of household registers and accounting books, and reforms to the tax system. These policies clearly indicated a direction toward a centralized state with the emperor at the apex. While their implementation and scope are debated, they served as the foundation for the later establishment of the Ritsuryo system.

Furthermore, construction of Naniwa Nagara Toyosaki Palace (Naniwa Palace) progressed, and in 652 the center of politics and diplomacy is believed to have been moved from Asuka to Naniwa Palace. Naniwa Palace also functioned as a frontline base for international exchange, and was a capital city that took advantage of its convenient geographic location for transportation with China and the Korean Peninsula. In the final years of Emperor Kotoku's reign, Prince Nakano Oe and Retired Empress Kogyoku returned to Asuka, while the emperor himself remained at Naniwa Palace, gradually isolating his political position.

In 654, Emperor Kotoku passed away at Naniwa Palace, and Retired Empress Kogyoku re-enthroned as Empress Saimei. Despite many difficulties, the reign of Emperor Kotoku is regarded as a groundbreaking era in which the direction of the formation of a ritsuryo state was clearly defined through the Taika Reforms.

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 characterized by active civil engineering projects and deep involvement in the affairs of the Korean Peninsula. Following the death of Emperor Kotoku, Empress Saimei ascended to the throne at Asuka Itabuki Palace, and 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 Hosho also stayed in Japan to seek support. In response to a 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.

During the reign of Emperor Tenji (668-672)

The reign of Emperor Tenji (668-672) began with Prince Nakano Oe's formal accession to the throne. Following the defeat at Hakusukinoe, the reorganization of the nation and strengthening of national defense became major priorities. In 668, Emperor Tenji relocated his base of operations from Asuka to Otsu Palace in Omi, aiming to establish a new political system. The move to Otsu is understood to have been intended to distance himself from the former power base in Asuka while taking advantage of the region's geographical location on the west shore of Lake Biwa to establish a defense system.

In terms of national defense, in 664, he deployed defenders to Tsushima, Iki, and Tsukushi, and established a communication network using signal fires. From 665 onward, incorporating the knowledge of defected engineers from Baekje, he constructed Korean-style mountain castles such as Ono Castle (Fukuoka), Kii Castle (Saga), and Nagato Castle (Yamaguchi), and in Tsukushi, he constructed a large earthwork and moat known as a water castle. These facilities are believed to have formed a defense network centered on northern Kyushu in preparation for invasions by the Tang and Silla dynasties.

In terms of domestic affairs, the first nationwide family register, the Kogo Nenshi (Kōgo Year Register), was created in 670. This led to the reorganization of the clan and surname system and the establishment of social status and household registration, which served as the basis for taxation and military service. The so-called "Ōmi Code" (Ōmi Code) was also compiled, which attempted to systematize 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 and successor, rather than his younger brother, Prince Ōama (later Emperor Tenmu), raising 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 no Kiyomihara Palace the following year in 673. This marked the clear transition of royal authority from the Tenji line to the Tenmu line.

Emperor Tenmu is interpreted as having broken away from the traditional political system reliant on powerful clans and developed a system of imperial family politics centered on the imperial family. He left the position of minister vacant, reorganized government offices such as the legal and military systems under the direct control of the emperor, and is thought to have personally overseen government affairs. He appointed members of the imperial family, including Empress Inuno Sanara (later Empress Jitō), to key positions, and pursued a policy of elevating the status of the imperial family over that of clans.

Emperor Tenmu also established eight surnames, reorganizing the clan and surname system and clarifying the social hierarchy. Another notable feature of his reign was his efforts to establish the foundations of the Ritsuryo system and building the framework for a centralized state. He is also credited with initiating the compilation of the Kojiki and Nihon Shoki, Japan's oldest historical texts, and sought to justify the emperor-centered order by revising national history in a way that favored the monarchy.

In terms of religion and culture, he protected Buddhism and laid the foundation for the flourishing of culture that would later be known as Hakuho culture. The construction of temples and the promotion of Buddhist culture, such as the construction of Yakushiji Temple, are also considered important policies of the Tenmu reign. Thus, the reign of Emperor Tenmu, following the change of government following the Jinshin War, was a time of strengthening imperial power and significant progress on the path to a Ritsuryo state.

During the reign of Emperor Jitou (690-697)

AThe reign of Empress Jitō (690-697) was a landmark period, marked by significant progress in the development of the Ritsuryo state system and the full-scale construction of capital cities. Empress Jitō was the daughter of Emperor Tenji and supported Emperor Tenmu's reign as empress. After Tenmu's death, she initially intended for Crown Prince Kusakabe to succeed her, but following his untimely death in 689, she ascended to the throne herself the following year in 690.

Empress Jitō continued Emperor Tenmu's policies and devoted herself to the development of the Ritsuryo system. The Asuka Kiyomihara Code is believed to have been enacted in 689, and a nationwide family register known as the Koin Nensei (Yearly Year Register) was created in 690, solidifying the foundations of Japan's legal system and administrative organization. These policies, which led to the later enactment of the Taihō Code, had a profound impact on the formation of Japan's Ritsuryo state.

Furthermore, Empress Jitō promoted the construction of Fujiwara-kyō, Japan's first fully-fledged grid-based capital, and relocated the capital there in 694. Fujiwara-kyō was a large-scale capital with a grid-like urban plan, and became a symbol of centralized state administration centered on the emperor. Culturally, she is also credited with contributing to the development of court waka culture through the waka poems preserved in the Manyoshu.

In 697, Empress Jitō abdicated in favor of her grandson, Prince Karu (Emperor Mommu), and while still involved in government affairs as Retired Emperor, she ensured a peaceful transfer of power. Her reign occupies an extremely important position in ancient Japanese history, both in terms of stabilizing the political system and establishing a path to a ritsuryo state.

During the reign of Emperor Mommu (690-697)

The reign of Emperor Mommu (697-707) was an important period in which the legal framework of the Ritsuryo state system was established. Emperor Mommu, the grandson of Empress Jitō and son of Prince Kusakabe, ascended to the throne at a young age, with Empress Jitō initially supporting him in government affairs as his guardian. This continued the policies of the Tenmu-Jitō administration while marking a transition to the next generation's rule.

The greatest achievement of this period was the enactment of the Taihō Code in 701, compiled primarily by Prince Ogata and Fujiwara no Fuhito. The Taihō Code was a culmination of the legal developments that had continued since the reigns of both Tenmu and Jitō. It was a written code that systematically organized "Ritsu" (criminal law) and "Ryo" (administrative and civil law). This established a legal framework for central and local bureaucracies, tax systems, household registrations, and land distribution, and the Ritsuryo state system is considered to have reached legal completion.

During the reign of Emperor Monmu, missions to Tang China resumed in 702, and the country actively introduced the Tang's advanced systems and culture. It is believed that Emperor Monmu also consolidated governance over surrounding regions, such as southern Kyushu and the Nansei Islands, and promoted national unification. Emperor Monmu married Fujiwara no Fuhito's daughter, Miyako, and they had Prince Sukuna, who would later become Emperor Shōmu.

In 707, Emperor Monmu passed away at the young age of around 25, and his mother, Empress Genmei, ascended to the throne and inherited the government. The reign of Emperor Monmu can be considered a turning point, as the framework for a Ritsuryo state was fully established through the enactment of the Taihō Code and preparations for its implementation.

Timeline of the Asuka period

592 AD	Soga no Umako assassinated Emperor Sutoku. The accession of Emperor Suiko took place. Prince Shotoku became the regent.
604 AD	Prince Shotoku established the Twelve Ranks of Cap and Gown.
604 AD	Prince Shotoku promulgated the Seventeen Article Constitution.
607 AD	Ono no Imoko dispatched Hai Seisei as an envoy of gratitude.
608 AD	Takamuko no Kuromaro, Soumin and Minabuchi no Shouan went to study abroad and witnessed the collapse of the Sui dynasty and the founding of the Tang dynasty.
645 AD	Taika Reform
663 AD	The Battle of Baekgang (Hakusukinoe). Emperor Saimei sent troops to aid Baekje (Kudara). To defend the Dazaifu (regional government office in Kyushu), guards (defenders) were stationed.
670 AD	The Kougo Nenjaku was created, which was a document summarizing the results of a population census.
672 AD	The Jinshin War occurred.Prince Oama emerged victorious in the Jinshin War.　As a result, the authority of the emperor increased and the system of public lands and people was established.
673 AD	Prince Oama moved the capital to Asuka Kiyonomiharamiya Palace and became Emperor Tenmu.
684 AD	The Eight Colors of Nobility were established," which refers to a system of eight hereditary noble titles.
690 AD	The Koin Nenjaku was created, which was a document summarizing the results of a population census. The system of divided fields, known as Kubunden, was introduced, under which plots of land were assigned to individuals and families.
694 AD	The capital was moved to Fujiwara-kyo.
701 AD	Emperor Monmu promulgated the Taiho Code, which was a legal code of Japan that was established a centralized government and administrative system.

Facilities where you can learn about the Asuka period

Osaka Museum of History - Naniwa Palace Site (Chuo-ku, Osaka)
http://www.mus-his.city.osaka.jp/news/zyousetu/b1.html

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/

Japanese History Digest