Emperor Tenmu Tenmu ' s reign lasted from 672 until his death in 686 . Traditional narrative . Tenmu was the youngest son of Emperor Jomei and Empress Saimei , and the younger brother of the Emperor Tenji . His name at birth was Prince Ōama ( 大海人皇子 : Ōama no ōji ) . He was succeeded by Empress Jitō , who was both his niece and his wife . During the reign of his elder brother , Emperor Tenji , Tenmu was forced to marry several of Tenji ' s daughters because Tenji thought those marriages would help to strengthen political ties between the two brothers . The nieces he married included Princess Unonosarara , today known as the Empress Jitō , and Princess Ōta . Tenmu also had other consorts whose fathers were influential courtiers . Tenmu had many children , including his crown prince Kusakabe by Princess Unonosarara ; Princess Tōchi ; Prince Ōtsu and Princess Ōku by Princess Ōta ( whose father also was Tenji ) ; and Prince Toneri , the editor of " Nihonshoki " and father of Emperor Junnin . Through Prince Kusakabe , Tenmu had two emperors and two empresses among his descendents . Empress Shōtoku was the last of these imperial rulers from his lineage . Events of Tenmu ' s life . Emperor Tenmu is the first monarch of Japan , to whom the title " tennō " was assigned contemporaneously — not only by later generations . The only document on his life was " Nihonshoki " . However , it was edited by his son , Prince Toneri , and the work was written during the reigns of his wife and children , causing one to suspect its accuracy and impartiality . Tenmu ' s father died while he was young , and he grew up mainly under the guidance of Empress Saimei . He was not expected to gain the throne , because his brother Tenji was the crown prince , being the older son of their mother , the reigning empress . After Tenji ascended to the throne , Tenmu was appointed crown prince . This was because Tenji had no appropriate heir among his sons at that time , as none of their mothers was of a rank high enough to give the necessary political support . Tenji was suspicious that Tenmu might be so ambitious as to attempt to take the throne , and felt the necessity to strengthen his position through politically advantageous marriages . Tenji was particularly active in improving the military institutions which had been established during the Taika reforms . In his old age , Tenji had a son , Prince Ōtomo , by a low - ranking consort . Since Ōtomo had weak political support from his maternal relatives , the general wisdom of the time held that it was not a good idea for him to ascend to the throne , yet Tenji was obsessed with the idea . In 671 Tenmu felt himself to be in danger and volunteered to resign the office of crown prince to become a monk . He moved to the mountains in Yoshino , Yamato province ( now in Yoshino , Nara ) , officially for reasons of seclusion . He took with him his sons and one of his wives , Princess Unonosarara , a daughter of Tenji . However , he left all his other consorts at the capital , Omikyō in Ōmi Province ( today in Otsu , Shiga ) . A year later , ( in 672 ) Tenji died and Prince Ōtomo ascended to the throne as Emperor Kōbun . Tenmu assembled an army and marched from Yoshino to the east , to attack the capital of Omikyō in a counterclockwise movement . They marched through Yamato , Iga and Mino province s to threaten Omikyō in the adjacent province . The army of Tenmu and the army of the young Emperor Kōbun fought in the northwestern part of Mino ( nowadays Sekigahara , Gifu ) . Tenmu ' s army won and Kōbun committed suicide ( Jinshin incident ) . As might be expected , Emperor Tenmu was no less active than former - Emperor Tenji in improving the Taika military institutions . Tenmu ' s reign brought many changes , such as : ( 1 ) a centralized war department was organized ; ( 2 ) the defenses of the Inner Country near the Capital were strengthened ; ( 3 ) forts and castles were built near Capital and in the western parts of Honshū — and in Kyushu ; ( 4 ) troops were reviewed ; and all provincial governors were ordered to complete the collection of arms and to study tactics . In 673 Tenmu moved the capital back to Yamato province on the Kiymihara plain , naming his new capital Asuka . The Man ' yōshū includes a poem written after the Jinshin conflict ended : At Asuka , Emperor Tenmu was enthroned . He elevated Unonosarara to be his empress . Events of his reign include : Tenmu reigned from this capital until his death in 686 . The actual site of his grave is known . This emperor is traditionally venerated at a memorial Shinto shrine ( " misasagi " ) at Nara . The Imperial Household Agency designates this location as Tenmu ' s mausoleum . It is formally named " Hinokuma no Ōuchi no misasagi . " Buddhism . In 675 Emperor Tenmu banned the consumption of animal meat ( horse , cattle , dogs , monkeys , birds ) , due to the influence of Buddhism . Politics . In " Nihonshoki " Tenmu is described as a great innovator , but the neutrality of this description is doubtful , since the work was written under the control of his descendants . It seems clear , however , that Tenmu strengthened the power of the emperor and appointed his sons to the highest offices of his government , reducing the traditional influence of powerful clans such as the Ōtomo and Soga . He renewed the system of " kabane " , the hereditary titles of duty and rank , but with alterations , including the abolition of some titles . Omi and Muraji , the highest kabane in the earlier period , were reduced in value in the new hierarchy , which consisted of eight kinds of kabane . Each clan received a new kabane according to its closeness to the imperial bloodline and its loyalty to Tenmu . Tenmu attempted to keep a balance of power among his sons . Once he traveled to Yoshino together with his sons , and there had them swear to cooperate and not to make war on each other . This turned out to be ineffective : one of his sons , Prince Ōtsu , was later executed for treason after the death of Tenmu . Tenmu ' s foreign policy favored the Korean kingdom Silla , which took over the entire Korean peninsula in 676 . After the unification of Korea by Silla , Tenmu decided to break diplomatic relations with the Tang dynasty of China , evidently in order to keep on good terms with Silla . Tenmu used religious structures to increase the authority of the imperial throne . During his reign there was increased emphasis on the tie between the imperial household and the Grand Shrine of Ise ( dedicated to the ancestor goddess of the emperors , Amaterasu ) by sending his daughter Princess Oku as the newly established Saiō of the shrine , and several festivals were financed from the national budget . He also showed favor to Buddhism , and built several large temples and monasteries . It is said that Tenmu asked that each household was encouraged to build an altar with a dais where a Buddha - image and a sutra could be placed so that family worshiping could be held , thus inventing the butsudan . On the other hand , all Buddhist priests , monks and nuns were controlled by the state , and no one was allowed to become a monk without the state ' s permission . This was aimed at preventing cults and stopping farmers from turning into priests . " Kugyō " . " Kugyō " ( 公卿 ) is a collective term for the very few most powerful men attached to the court of the Emperor of Japan in pre - Meiji eras . In general , this elite group included only three to four men at a time . These were hereditary courtiers whose experience and background would have brought them to the pinnacle of a life ' s career . During Tenmu ' s reign , this apex of the " Daijō - kan " included : Era of Tenmu ' s reign . The years of Tenmu ' s reign were marked by only one era name or " nengō " which was proclaimed in the final months of the emperor ' s life ; and " Shuchō " ended with Tenmu ' s death . Non " - nengō " period . The early years of Tenmu ' s reign are not linked by scholars to any era or " nengō " . The Taika era innovation of naming time periods – " nengō " – was discontinued during these years , but it was reestablished briefly in 686 . The use of " nengō " languished yet again after Tenmu ' s death until Emperor Mommu reasserted an imperial right by proclaiming the commencement of Taihō in 701 . In this context , Brown and Ishida ' s translation of " Gukanshō " offers an explanation about the years of Empress Jitō ' s reign which muddies a sense of easy clarity in the pre - Taihō time - frame : Wives and Children . Empress : Princess Uno - no - sarara ( 鸕野讃良皇女 ) ( Empress Jitō ) ( 645 – 703 ) " Hi " : Princess Ōta ( 大田皇女 ) ( 644 – 667 ) , daughter of Emperor Tenji " Hi " : Princess Ōe ( 大江皇女 ) ( ? – 699 ) , daughter of Emperor Tenji " Hi " : Princess Niitabe ( 新田部皇女 ) ( ? – 699 ) , daughter of Emperor Tenji " Bunin " : Fujiwara no Hikami - no - iratsume ( 藤原氷上娘 ) ( ? – 682 ) , daughter of Fujiwara no Kamatari " Bunin " : Soga no Ōnu - no - iratsume ( 蘇我大蕤娘 ) ( ? – 724 ) , daughter of Soga no Akae " Bunin " : Fujiwara no Ioe - no - iratsume ( 藤原五百重娘 ) , daughter of Fujiwara no Kamatari Court lady : Nukata no Ōkimi ( 額田王 ) Court lady : Munakata no Amako - no - iratsume ( 胸形尼子娘 ) , daughter of Munakata - no - Kimi Tokuzen Court lady : Shishihito no Kajihime - no - iratsume ( 宍人梶媛娘 ) , daughter of Shishihito - no - Omi Ōmaro