Emperor Kogen (孝元天皇)
Emperor Kogen (273 B.C. – October 14, 158 B.C.) is the eighth emperor (reigned from February 21, 214 B.C. to October 14, 158 B.C.) written in "Kojiki" (The Records of Ancient Matters) and "Nihonshoki" (Chronicles of Japan). He is also called Oyamatoneko hikokunikuruno mikoto or Oyamatoneko hikokunikuruno mikoto (in Kojiki).
The title 'Yamatoneko' is used for the seventh Emperor Korei, the eighth Emperor Kogen, the ninth Emperor Kaika, and, after an interval, the twenty-second Emperor Seinei (Kojiki), and is also found in the titles of such emperors as Jito, Monmu, Genmei, and Gensho (Nihonshoki and "Shoku Nihongi" [Chronicle of Japan Continued]), who existed in the period from the late seventh through the early eighth century when the compilation of the Kojiki and Nihonshoki was in the final stage. Therefore, it is highly likely that the titles for the seventh, eighth and ninth emperors were made with reference to the titles of the existent emperors in the later period when the compilation of the Kojiki and Nihonshoki was in the final stage.
He is one of so-called Kesshi-Hachidai (Eight Undocumented Sovereigns) and is generally thought to have been nonexistent. However, a genealogy indicating the existence of Obiko no Mikoto, the first Prince of the Emperor Kogen, was engraved on kinsakumei tekken (an iron sword with gold-inlaid inscriptions) unearthed from Inariyama-kofun Tumulus; then more people now believe that the Emperor Kogen actually existed.
Imperial palace
His palace was Karu no sakaihara no miya (located at Musanimasu-jinja Shrine in Mise Town, Kashihara City, Nara Prefecture according to legend).
Achievements
No specific records exist. He was formally installed as Crown Prince in January, 255 B.C., and after the Emperor Korei passed away in February, 215 B.C., he was enthroned in January next year. He passed away after 57 years of reign at the age of 57 according to Kojiki or 116 according to Nihonshoki.
Imperial mausoleum
He is said to have been buried in Tsuruginoike no shimanoue no misasagi. The mausoleum is identified as the first to third mounds of Nakayamazuka-kofun Tumulus (two round and one keyhole-shaped burial mounds) in Ishikawa Town, Kashihara City, Nara Prefecture.