Emperor Kōtoku (孝徳天皇, Kōtoku Tennō), born in 597 and died on November 24, 654 was the thirty-sixth emperor of Japan, according to the traditional order of succession. He reigned from July 12, 645 until his death.

Emperor Kōtoku Genealogy

His personal name was Prince Karu. A descendant of Emperor Bidatsu, he was a son of Prince Chinu by Princess Kibihime, and thus a younger brother of Empress Kōgyoku whom he succeeded.

Chinu was a son of Prince Oshisaka-hikohito no Ōe, himself a son of Emperor Bidatsu. Kōtoku had at least three consorts, including his empress, Hashihito no Himemiko (Princess Hashihito), the daughter of Emperor Jomei and his sister Kōgyoku.

Empress and consorts

• Princess Hashihito, daughter of Emperor Jomei and Empress Takara; empress in 645; empress dowager; died in 665 ;
• Abe no Otarashi-hime, daughter of Abe no Kurahashi Maro; imperial wife; of whom he had one child:
• prince Arima (640-658)
• Soga Chi no Iratsume, daughter of Soga Ishikawamaro; imperial wife.

Biography of Emperor Kōtoku

In 645, during the first reign of his sister Kōgyoku, the Soga clan attempted to take control of the court, and Prince Naka no Ōe assassinated Soga no Iruka, the clan leader, just in front of the throne (see the article Itsushi no hen). Shocked, the empress abdicates in favor of her son, Crown Prince Naka no Ōe, but he insists that it be Kōtoku who ascends the throne, which he does two days after these events.

Emperor Kōtoku's Taika Era

The Taika (大化, Taika) era began in the third year of Empress Kōgyoku's reign (645). Kōtoku, upon ascending the throne, introduces to Japan the use of nengō or honorific titles of the years of the emperors' reign. He names the first years of his Taika.

• Taika gannen (大化元年) or Taika 1 (645): Kōtoku introduces the Taika reform (大化の改新, Taika no kaishin). This systematic reform (律令, ritsuryō or ritsuryô) consists of a series of articles written during the reign of Emperor Kōtoku. The emperor divided the empire into eight provinces, and regulated the rank of all government officers, distinguishing them by nineteen caps of different shapes and colors, according to their rank.
• Taika 1 (645): emperor Kōtoku left Asuka, the classical capital until then. He transferred the capital to Naniwa in the vicinity of Osaka Bay and centralized power there. Kōtoku resided in a palace, Toyosaki no Miya in Nagara, built on a promontory in the vicinity of Naniwa in Settsu (摂津国) province.
• Taika 2, the 1st of the 1st month (646): Kōtoku sets the days for major court hearings. He establishes, in all the provinces of the empire, magistracies, gates, and post-houses, divides the country according to mountains and rivers, places governors in each province, and fixes the wages of porters. He appointed chiefs in the districts and villages, and was the first to take a census of the population and land product of each place and to levy taxes. He introduced infantry and cavalry reviews, ordered to take for every hundred families a woman for the palace service. An officer was sent every year to each province to examine the conduct of the governors. He also had stores and arsenals built. The right-wing minister (右大臣, udaijin) Soga Yamada Ishikawa Maro was charged with warning him of any faults he might commit in government. It was he who invented and introduced much of the etiquette that is still observed at court. Naka no Ōe-shinno and the regent Nakatomi no Kamatari advised him on all these measures.
• Taika 5, the 7th of the 3rd month (649): death of the Left Minister (左大臣, sadaijin) Abe no Kurahashi Maro.
• Taika 5, 20th of the 4th month (649): Kose no Toko no Ō-omi (593-658) was made a sadaijin just after the death of his predecessor.
• Taika 5, 3rd month (649): Sogo no Kiyouga, younger brother of the udaijin Soga Yamada Ishikawa Maro, having informed the emperor that his older brother was hatching a conspiracy, Kōtoku sent armed people to his home to put him to death. Yamada committed suicide. Later, when his innocence was proven, his brother Kiyouga was exiled to Tokachi (十勝国) on the island of Hokkaidō, then a wild and desolate land.
• Taika 5, 4th month (649): Ōtomo Nagatoko no Muraji was made a sadaijin and given the purple hat.
• Taika 5 (649): the establishment of the new system of government (the hasshō hyakkan), eight administrations or ministries and one hundred offices.
• Taika 6 (650): a white pheasant was sent to the emperor from the province of Nagato, which was considered a good omen. The emperor was very pleased with it, and summoned all the people of his court to show them this bird. Kōtoku ordered that the prince of Nagato be advanced in rank by one degree.

According to the Nihon shoki, Kōtoku had a noble personality, was sympathetic to Buddhism, and was very inspired by China.

In 645, he created a new city in a place called Naniwa, and moved the capital from Asuka to this new city.

The new capital has a seaport and is therefore perfect for trade and diplomatic activities. The following year, Kōtoku implements the Taika reform, reshaping the empire along Chinese lines.

Emperor Kōtoku's Hakuchi era

The Hakuchi era began in the sixth year of Taika (650). On this occasion, the nengō was changed to Hakuchi, which means white pheasant.

• Hakuchi gannen (白雉元年) or Hakuchi 1 (白雉一; 650): Kōtoku requested that all Yamato prisoners be released.
• Hakuchi 2 (651): the emperor had a sixteen-foot high image of Buddha made, from which a thousand other images of this deity were engraved. He had two thousand religious men and women assembled in his palace, charged with reading the books of the law of Buddha (一切経, issai kyō). On this occasion, the court was illuminated with two thousand seven hundred lanterns.
• Hakuchi 4 (653): the emperor sent Kiso no Osani at the head of an embassy, to the Court of the Tang emperor, who received her in solemn audience. Several Japanese priests accompanied this embassy. Among them was Zio yè, son of Fujiwara no Kamatari, who had since founded the great temple of the mountain Fafou-no miné-no kaï san in the province of Yamato. The embassy returned to Naniwa with Chinese books and several treasures from China.
• Hakuchi 5 (654): Kōtoku died at the age of 59, after a reign of ten years-five years of the nengō Taika, and five years of the nengō Hakuchi.
• Hakuchi 6 (655): Saimei was the new honorary name of Empress Kōgyoku, who took over the government she had previously ceded to him upon Kōtoku's death. This is the first instance in Japanese history where the same person occupied the throne a second time. At her suggestion, the empress moved her residence from Naniwa to Kawara no Miya Palace in the Asuka District of Yamato Province. A huge amount of rats and mice arrived from Naniwa. Soon after, Saimei left Asuka District, and went to reside in Okamoto no Miya Palace in Ōmi Province. The minister of the Center (内大臣, naidaijin) Nakatomi no Kamatari was appointed regent of the empire.

Naka no Ōe continued to hold the rank of crown prince, and was the de facto leader of the government.

In 653, he proposed moving the capital to Yamato province again. Kōtoku refused, but the prince ignored this advice and returned to Asuka.

Many members of the court, including Empress Hashihito followed him, and the emperor was left almost alone and forgotten in his palace.

He died the following year of illness. With Naka no Ōe still refusing to ascend the throne, his mother, the former empress Kōgyoku, returned to the throne under the new reign name of Saimei (斉明).