How do balks restrict scoring in balkline billiards?

In balkline billiards, the table is divided into eight areas called balks by lines drawn parallel to the cushions. These restrictions were implemented to prevent expert players from trapping the object balls in a corner and scoring indefinitely through repetitive, simple shots.1

When both object balls are positioned within a single balk, a player is limited in how many caroms they can score. Depending on the specific game variant, the player may only score once or twice before they are required to drive at least one of the object balls out of that balk.1

To prevent players from circumventing these rules by positioning balls near the intersection of a balkline and a cushion, additional squares known as "anchors" are marked at these intersections. These anchors are treated as separate, restricted balks, ensuring that scoring remains challenging even near the edges of the table. Scoring in the large central area of the table remains unrestricted.1