Wikipedia
Stavnsbånd
The Stavnsbånd was a serfdom-like institution introduced in Denmark in 1733 in accordance with the wishes of estate owners and the military. It bonded men between the ages of 14 and 36 to live on the estate where they were born. It was possible, however, to purchase a pass releasing one from this bondage. So, in practice, estate owners and their sons were not particularly bonded to live on their estates.
The Stavnsbånd was introduced because of a crisis in 1730 where a lot of peasants tried their luck in the cities. That meant that there was a need workers on the farms, and for people to fight.