This is an unusual name change.
Buyeo Zenkō (?-691)
His family were the ruling dynasty of the Baekje state in the Korean Peninsula. They migrated to Japan. While his brother was sent back to represent the family, Zenko stayed behind and assimilated into Japanese society.
Kudara no Konikishi Zenkō (691-death)
This was an official policy of the Japanese nobility to give special titles to foreign nobles.
I can see how this might be an unusual choice of a name, because it would be like naming someone “Zack King-Of-Baekje,” or “Zack Baekjeking.” Of course, hyphenated periphrastic surnames are not impossible, for there is the Surinamese family Tjin-A-Djie.
- (Image Attribution) Nisiguti. “Kudarao Shrine.” Wikipedia. 1 January 2007. CC BY-SA 3.0.
- “Kudara no Konikishi clan.” Wikipedia.