Billiard game Balkline. In light of these phenomenal skill developments in straight rail, the game of balkline soon developed to make it impossible for a player to keep balls in a corner for an interminable period. A balkline (not to be confused with baulk line, which pertains the game of English billiards) is a line parallel to one end of a billiard table. In the games of balkline - 18.1 and 18.2 (pronounced "eighteen-point-two") balkline, among other more obscure variations - the players have to drive either one ball or two balls (respectively) past a balkline set at 18 inches from the rail after a fixed number of shots.