Emperor Tenmu
Emperor Tenmu was the 40th emperor of Japan according to the traditional order of succession. He was born Prince Ōama around 630, the son of Emperor Jomei and Princess Takara. Ruling from 673 to 686, during the Asuka period, his life is mainly documented by the chronicles Nihon Shoki and Kojiki, as well as the poetry collection Man'yōshū.
Little is known of Ōama's early life. During the rule of his elder brother Tenji, Ōama was ambiguously favored as his successor, but was gradually bypassed in favor of Tenji's son Prince Ōtomo. Tenji allegedly offered Ōama the throne during an illness in 671, but fearing a conspiracy against him, Ōama declined and left to serve as a monk at Yoshino Palace. Tenji died soon after. The following year, Ōama received word that Ōtomo, now ruler, was planning to kill him. He fled Yoshino with a group of followers, beginning the Jinshin War. Along with a group of retainers and the governor of Ise Province, Ōama was able to block off the mountain passes to the northern and eastern provinces, where he raised an army against his nephew. Ōtomo was defeated and forced to commit suicide. Ōama took the throne under the name Tenmu.
Tenmu made a number of political reforms, modeling his government after the centralized state of Tang China. He was likely the first Japanese ruler to use the title of 2= and the first to be described as a divine being in his lifetime. He redistributed political titles among his family and political supporters and created four new ranks at the top of the 2= noble title system. He selected a site for a new capital around 683, on which was likely built Fujiwara-kyō. He was an enthusiastic supporter of both Buddhism and the goddess Amaterasu, making various reforms to Buddhist clerical governance and elevating Amaterasu's Ise Shrine to preeminence in Japan.
Tenmu's health began to decline in 685. In attempt to gain divine favor, the imperial court sponsored large-scale Buddhist rituals, but he died in 686. This began a mourning period and interregnum almost twice the length as usual, during which both of his crown princes died: Prince Ōtsu was executed later the same year, likely on the orders of Tenmu's consort Uno-no-sarara, while Prince Kusakabe died of ill health in 689. Uno-no-sarara ascended to the throne in 689 as Empress Jitō.
Background and early life
Prince Ōama was the son of Emperor Jomei of Asuka Japan and his consort Princess Takara, and the younger brother of Naka no Ōe. His date of birth is unclear; traditional sources date his birth to either 613 or 621, but this would make him older than Naka, born in 626. Some modern historians have estimated a date around 630, owing to the existence of a middle sister, Princess Hashihito, between the two brothers. Due to the much older date in traditional sources, archaeologist Yuji Seki theorized that Ōama may have been the son of Takara and her first husband, Prince Takamuku.Jomei had ascended to the throne in 629, around the time of Ōama's birth, following the death of the long-reigning Empress Suiko. Suiko had never selected an heir after the death of Prince Shōtoku in 622, leading to a protracted succession dispute between Jomei and Shōtoku's son Yamashiro. Although Jomei took the throne with the support of Senior Minister Soga no Emishi, Yamashiro continued to press his claim.
Upon Jomei's death in 641, Yamashiro stood as the strongest potential candidate for emperor, as Jomei's crown prince Naka no Ōe was only sixteen years old. However, Emishi continued to oppose Yamashiro, and proposed Jomei's son Furuhito no Ōe take the throne. Lacking significant backing, Emishi agreed to a compromise following the precedent of Empress Suiko's ascension, and Princess Takara took the throne as Empress Kōgyoku. Emishi's son Soga no Iruka became the dominant political figure during Kōgyoku's reign, seizing control of administrative affairs and purging many of his opponents, including Yamashiro and his family. A triumvirate of three statesmen—Nakatomi no Kamatari, Soga no Ishikawa Maro, and Prince Naka no Ōe—assassinated Iruka in 645. Kōgyoku abdicated, initially intending for Naka to take the throne; however, with pressure from Nakatomi, her brother Prince Karu took the throne as Emperor Kōtoku.
Kotoku was succeeded by the former Empress Kōgyoku in 655, who reigned again under the new name Saimei. In 660, the Korean kingdom of Baekje fell to a combined Tang–Silla force. The following year, Saimei, alongside Naka and Ōama, sailed to Kyushu to oversee the construction of an armada to invade Korea and restore Baekje. Saimei died in Kyushu in the 9th month of that year, and Prince Naka was appointed as an interim regent, unwilling to officially take the throne; two years later, the Japanese armada was defeated. Naka oversaw the expansion of fortifications around Kyushu, seeking to defend against a possible Sino-Korean invasion, and integrated provincial elites into the court rank system. These efforts increased royal authority, but created considerable unrest among the Japanese clans.
Ōama's first wife was Princess Nukata, the daughter of an obscure noble named Prince Kagami. Ōama also married four of Naka's daughters, likely as an effort to lessen the influence of prominent families such as the Soga over future successors. Among these was Uno-no-sarara, who became his chief consort. He married five other wives, including Kamatari's daughter Ioe. Around 660, Nukata was forced to leave Ōama in order to marry Prince Naka.
Rise to power
Naka appears to have ambiguously supported Prince Ōama as his successor; the 8th century chronicle Nihon Shoki inconsistently labels him as a crown prince. Naka moved the capital to the Ōtsu Palace in Ōmi Province in 667 and was formally enthroned as Emperor Tenji the next year. Following this, he distanced himself from his brother to support his own favorite son, Prince Ōtomo, as his successor. The Tōshi Kaden, an 8th century history of the Fujiwara clan, relays an anecdote from Tenji's coronation banquet in 668, stating that Ōama startled Tenji by throwing a spear into the floorboards in front of him. Tenji is said to have drawn his sword and prepared to kill his brother, but the Fujiwara ancestor Nakatomi no Kamatari calmed his temper and saved the crown prince.Ōtomo was granted the title of 2= in early 671. The following day, either Ōama or Ōtomo was tasked with performing court duties; the chronicles are unclear and contradictory on who was entrusted with this role. In the eighth month of that year, Tenji became seriously ill and summoned Ōama, offering him the position as his successor. Either unwilling to become emperor or fearing that his acceptance would be used as pretext to have him removed from succession, Ōama refused, instead proposing that Tenji's consort Yamatohime serve as empress, with Ōtomo as her regent. Ōama shaved his hair and asked permission from Tenji to become a Buddhist monk; Tenji accepted two days later, and Ōama traveled to Yoshino Palace in southern Yamato Province with a small group followers. It is unknown if Tenji genuinely sought to offer the throne to his brother, or if the offer was made as part of a plot against him.
Jinshin War
Tenji died in the 12th month of 671. Although Ōtomo was recognized as his successor by the imperial court in Ōmi, later chronicles such as the Nihon Shoki do not recognize him as an emperor, and it is unclear if he was ever enthroned; he may have simply controlled affairs as the designated heir, possibly with Yamatohime as an uncrowned empress regnant. The imperial court suspected a conspiracy on Ōama's part, and cut him off from receiving supplies from the capital. In the sixth month of 672, Ōama received a report from his political allies in Mino Province that Ōtomo was plotting to attack him, and fled east on horseback, beginning a succession dispute known as the Jinshin War. Alongside a small group of retainers and soldiers from Yamato Province, he was accompanied by Uno-no-sarara and their eleven-year-old son Kusakabe.File:Three barriers in Japan.png|thumb|Japanese map of locations in ancient eastern Kansai. The Suzuka Barrier is marked at the bottom-right, with Fuwa Pass above it. Ōmi is marked at the southern end of Lake Biwa.|alt=A topographic map of central Japan with locations labeled in Japanese
Ōama was limited by the small group of soldiers which came to support him. However, he was able to receive the support of the governor of Ise Province, who sent a force of five hundred soldiers to close the Suzuka Barrier, one of two mountain passes allowing access to the eastern provinces from the Kansai region. Following this, he was additionally able to gain support from officials in Owari and Mino, and possibly from the governors of Shinano and Kai. However, most governors were appointed directly by the Ōmi court, and continued to recognize its rule. Various local chieftains from across the eastern and northern provinces formed an important wellspring of support: he was able to mobilize a large number of supporters in eastern Japan, especially including the chieftains of the Hokuriku region, which had generally been affiliated with those in Owari and Mino. In Yamato, the powerful Ōtomo clan sided with Ōama, likely due to their opposition to the dominant Soga clan and the court's move to Ōmi. A strong hatred of Ōtomo's Bakejean generals may have also pushed the Ōtomo and the immigrant Yamatonoaya clan to support Ōama.
While Ōama was able to gain a significant amount of support in the north and east, the Ōmi court was unsuccessful in reinforcing his armies from the western and southern provinces. Despite this, pro-Ōmi forces were able to push back a contingent of Ōama's troops in Yamato Province early in the seventh month of 672. After this, Ōama split his main force into three armies: the largest marched through Fuwa Pass and along the southern shore of Lake Biwa, another went along the north of the lake, and the last retreated back through Mino and Ise to reinforce the troops in Yamato. Although shaken by a night cavalry raid, Ōama's largest army routed Ōtomo's forces at Seta, just to the southeast of Ōmi. Prince Ōtomo was forced to commit suicide by the end of the seventh month. Ōama executed or banished his top officials, but pardoned many of the other ministers of the Ōmi court. Ōama was enthroned at Asuka in 673. He is often referred to during his reign by his posthumous name, Emperor Tenmu 2=天武.