Carom billiards
Generally, the differences between one balkline game and another are defined by two different things: 1) where the balkines are drawn on the table, and 2) the number of points that are allowed in each balk space before at least one ball must leave that region of the table. Balkline games are named by giving two numbers that tell us about the spacing used and how many points can be scored in the balk spaces. The first number  tells us how many inches from the rail the balkine will be drawn. The second number after a "dot", indicates the number of points that can be scored in the balk spaces before the balls must leave it (that number is always either one or two). So, for example, the name 18.2 balkline, tells us that balklines are drawn  distant from each rail, and only two points are allowed in a balk space before a ball must leave that area.