Emperor Keiko (景行天皇)
Emperor Keiko (13 B.C. - December 23, A.D. 130) was the twelfth emperor (reign: August 22, A.D. 71-December 23, A.D. 130), being described in "Kojiki" (The Records of Ancient Matters) and "Nihonshoki" (Chronicles of Japan). A Japanese-style posthumous name was 大足彦忍代別天皇 (Otarashihiko oshirowake no Sumeramikoto) and it was written as 大帯日子淤斯呂和氣天皇 in Kojiki. His name is written as 大足日足天皇 in "Fudoki" (description of regional climate, culture, etc.). His name is written as Otarashihiko (大帯日子天皇、大帯日古天皇、大帯比古天皇) in Fudoki. He was the father of Yamatotakeru-no-Mikoto.
Not only the twelfth Emperor Keiko, the thirteenth Emperor Seimu and the fourteenth Emperor Chuai, but also the thirty-fourth Emperor Jomei and the thirty-fifth Emperor Kogyoku, who really existed and were certainly on the throne in the early seventh century, had the title "Tarashihiko." For this reason, there is a theory that the title "Tarashihiko" was made and used in the early seventh century, and this title was given to the twelfth to fourteenth Emperors after the seventh century, so existence of Emperor Keiko is being questioned.
Story of Yamato Takeru no Mikoto is described in most part of Kojiki and Nihonshoki, while Teiki (a genealogy of the imperial family) is described in the rest part of them, so their historicity is questionable. But if we assume that he really existed, he might be alive in the early fourth century.
Imperial Palace
The capital was Makimuku no hishiro no miya (it is considered to be possibly current Anashi, Sakurai City, Nara Prefecture). In his later years, he visited Omi Province in 128, and after he stayed in Shigatakaanahomiya (present Anou, Otsu City, Shiga Prefecture) for three years, he died in 130.
Achievement
Dates described below follow the chronology of Nihonshoki for expediency.
In the year of 8, he was formally installed as Crown Prince. In August, 71, he ascended the throne and appointed Harima no inabi no ooiratsume to the Empress the next year.
In 74, he visited Mino Province and stayed at Kukurinomiya (Kani City, Gifu Prefecture). He took Yasakairibine as his wife.
Tours to Kyushu
In 82, since Kumaso (a tribe living in the ancient Kyushu district) disobeyed him, the Emperor himself left for the west to conquer them in August. He got the information about rebels from Kamunatsusohime at saba (the land under direct control of an emperor), Suo Province (Hofu City, Yamaguchi Prefecture) and killed them. Then, he entered Chikushi (Kyushu) and set up the temporal shrine in Miyako-gun, Buzen Province (Yukuhashi City, Fukuoka Prefecture). After he executed tsuchigumo (those in ancient times who were not subjects of the Yamato court) in Okita, Bungo Province, he finally entered Hyuga Province. He made a daughter of Kumaso Takeru kill his father, and suppressed Kumaso. He stayed at Hyuga takayanomiya (it is considered possibly to be Nishimoro City, Miyazaki Prefecture) for six years. In March, 88, he left for the capital, and after touring Kuma no agata (Kuma Gun, Kumamoto Prefecture), Ashikita (Ashikita Gun, Kumamoto Prefecture), Takaki no Agata (Isahaya City, Nagasaki Prefecture), Aso no kuni (Aso gun, Kumamoto Prefecture) and Ikunohanomura (Ukiha gun, Fukuoka Prefecture), he returned in September the next year. Meanwhile, this punitive expedition of the Emperor is not described in Kojiki at all.
In July, 95, he dispatched TAKENOUCHI no Sukune to inspect each region of Hokuriku and Toho.
Activities of Yamato Takeru no Mikoto
In August, 97, Kumaso disobeyed the Emperor again. In October, Yamato Takeru no Mikoto was dispatched to conquer Kumaso. Yamato Takeru no Mikoto murdered Kawakami no Takeru and reported on his mission to Emperor Keiko next year. In October, 110, Yamato Takeru was ordered to conquer Ezo (northerners) by the Emperor. On his way, he received the Kusanagi no tsurugi from Yamatohime no mikoto, his aunt, at Ise Jingu Shrine. He entered Mutsu Province and suppressed Ezo without fighting. After he returned to Owari Province from Hitakami no kuni via Nihari (Makabe gun, Ibaragi Prefecture), Sakaorimiya in Kai Province, and Shinano Province, he got married to Miyazu-hime (Princess Miyabi). After that, he went off to Omi Province, but he became ill by a curse of Kojin (god of a cooking stove) of Mt. Ibuki. Although he entered Ise Province with that poor physical condition, he became seriously ill and died at Nobono (Kameyama City, Mie Prefecture) in 113. He was buried in Yamato Takeru ritual site. According to Kojiki, it is said that he wrote a poem "Kunishinobi uta" (a song to remember the country) with thinking of Yamato shortly before his death; this poem became very popular among soldiers dispatched to East Asia during the Pacific War.
Yamato wa kunino mahoroba tatanazuku, aokaki yamagomoreru, yamato shi uruwashi (Great Yamato, of all lands most supreme! Enclosed by ranks of verdant banks on surrounding hills, Great Yamato-unmatched for beauty!) (songs and ballads No.31 of Nihonshoki).
In 123, Emperor Keiko cherished the memory of Yamato Takeru, his son, and went on a tour of Togoku (eastern country, eastern provinces, Kanto provinces). After he returned from Togoku, he stayed at Ise and went back to Makimuku no miya in September next year.
In 128, he visited Omi province and stayed Takaanaho palace for three years. In November, 130, he died at the age of 143. According to Kojiki, he died at the age of 137.
Misasagi (Imperial mausoleum)
He was buried in Yamanobe no michinoeno misasagi. In Kojiki, there is a description that "Emperor Keiko's misasagi is in Yamanobe no michi noe."
Currently, this misasagi is identified with Shibutanimukaiyama-kofun Tomb (large keyhole-shaped tomb mound, 300m in total length) in Shibutani cho, Tenri City, Nara Prefecture.