Lines of Action

Below are several examples of moves: White can move the highlighted checker exactly two cells to the right because there are exactly two checkers in the same line. White can move the highlighted checker in the specified direction exactly three cells because there are exactly three checkers in the same line (two whites and one black). The reason is that there are three checkers in this line (two blacks and one white) but moving exactly three cells requires jumping over the opponent’s (white) checker.

Source: www.iggamecenter.com