Wikipedia
The Odelsrett is an ancient Scandinavian allodial title which has survived in Norway as odelsrett and existed until recent times in Sweden as bördsrätt.
The Norwegian law stipulates the right, when a farm is to be sold, of any member of the family, by the principle of primogeniture, to buy it, consistent with Åsetesrett.
If the property is sold to a stranger, family members have the right within a specified period of time (which varies over history, but ten years can be considered typical of recent usage) to redeem it at the price paid, with the additional cost of the improvements.
If there is controversy, appraisers are appointed.
Later law modified this, so that an owner selling his farm may determine whether he renounces for himself and heirs this right.
It has been argued that this law served as a mainstay to the long-lasting agrarian culture in Norway.