basic strategy for black - the barricade
Hnefatafl games often feature a desperate battle for control of one of the corners.
Here are three ways in which black can block off a corner, to prevent the king escaping that way. These positions are known as barricades. Black wants to barricade all four corners if possible. Remember that a single black warrior standing right next to the corner square is vulnerable to being captured. In the first two diagrams, this is not a problem as they are standing further away from the corner square. In the third diagram, the warrior next to the corner is protected by the one next to it, which stops white coming in to capture it.