Hōgen (era)

Hōgen (保元^?) was a Japanese era name (年号,, nengō,^?, lit. "year name") after Kyūju and before Heiji. This period spanned the years from April 1156 through April 1159. The reigning emperors were Emperor Go-Shirakawa-tennō (後白河天皇^?) and Emperor Nijō-tennō (二条天皇^?).

...
Wikipedia