Emperor Anko (安康天皇)
Emperor Anko (c. 401 - September 24, 456), who reigned from January 28, 454, to September 24, 456, was the twentieth Emperor. He was also known as Anaho no Sumeramikoto (Emperor) or Anaho no Miko (Prince). Emperor Anko is identified as King Ko of Wa (supposedly, Japan) among the Five Kings of Wa described in Chinese history books "So-jo" (Sung-shu in Chinese or the Book of Song) and "Ryo-jo" (Liang-shu in Chinese or the Book of Liang).
It was Isonokami no anaho no miya Palace in the capital (which was allegedly located in present-day Tamachi or Tabe, Tenri City, Nara Prefecture).
In February, 453, Emperor Ingyo demised.
Ingyo's retainers did not follow the Crown Prince Kinashi no Karu no Miko due to his previous conviction for incest, and they took side with the Crown Prince's younger brother, Anaho no Miko.
Karu no Miko assembled soldiers to kill Anaho no Miko. However, disappointed by an adverse situation in which the retainers turned against him one after another, Karu no Miko finally hid in the residence of MONONOBE no Omae no Sukune. Although Karu no Miko was beleaguered by the soldiers led by Anaho no Miko, the battle was avoided at the discretion of Omae no Sukune, and Karu no Miko killed himself (but, according to ''Kojiki'' [literally, the Records of Ancient Matters], Karu no Miko was exiled to Dogo-onsen). Thus, Anaho no Miko ascended to the imperial throne in December.
In 454, Emperor Anko, who believed the slanderous report by Ne no Omi, executed Okusaka no Miko who was a son of Emperor Nintoku, and the next year Emperor Anko took Nakashihime, the ex-wife of Okusaka no Miko, as his empress consort.
In September 24, 456, Emperor Anko was assassinated by Mayowa no Okimi, a child by Nakashihime's former marriage. Emperor Anko died at the age of 56 according to the ''Kojiki'' and ''Kujiki'' (ancient Japanese historical text), or 54 according to "Teio hennenki" (literally, Annals of the emperor).
Although the Emperor passed away without designating the crown prince, it is considered that he planned to choose his cousin Ichinohe (or Ichinobe) no Oshiha no Miko (son of Emperor Richu) as his heir to the imperial throne.
Alleged Incest Theory
While Emperor Anko's brother Kinashi no Karu no Miko was suspected of incest, one theory has it that Emperor Anko, too, allegedly committed incest. This is based on a statement in the "Kojiki" that Emperor Anko took his older sister, Nagata no Oiratsume no Ojo (Nakashihime), as his empress consort after he had executed Okusaka no Miko. However, the Yuryaku-ki of "Nihon shoki" (literally, Chronicles of Japan) stated that the wife of Emperor Anko was Nakashi no Ojo, a daughter of Emperor Richu, and annotated that her alternative name was Nagata no Oiratsume no Ojo. According to another theory, Emperor Anko and his wife were allegedly siblings with different mothers.
Imperial Tomb and Mausoleum
Emperor Anko was buried in Sugawara no fushimi no nishi no misasagi Mausoleum. The mausoleum is identified as Kojo-ichigo-fun (literally, old castle No.1 tumulus) at 4-chome, Horai, Nara City, Nara Prefecture. However, as a result of research conducted in recent years, the Kojo-ichigo-fun Tumulus is widely viewed not to be a tumulus but the ruin of a medieval mountain castle.