Oupahat

Ouparath, also Ouparaja, or Uparaja, is the position of deputy or second king in Laos, Siam and Cambodia.

In Siam the Ouparath system was abolished by king Chulalongkorn, when the deputy king prince Bovorn Vichaicharn died in 1885. Usually the deputy king was the brother of the king, and was the heir to the throne king died.