Chōgen (長元) was a Japanese era name (年号, nengō, lit.
"year name") after Manju and before Chōryaku.
This period spanned the years from July 1028 through April 1037.
[1] The reigning emperors were Go-Ichijō-tennō (後一条天皇) and Go-Suzaku-tennō (後朱雀天皇).
[2]