A point occupied by a single checker of either color is called a blot. If an opposing checker lands on a blot, the blot is hit and placed on the bar.
Any time a player has one or more checkers on the bar, his first obligation is to enter those checker(s) into the opposing home board. A checker is entered by moving it to an open point corresponding to one of the numbers on the rolled dice.
For example, if a player rolls 4 and 6, he may enter a checker onto either the opponent's four point or six point, so long as the prospective point is not occupied by two or more of the opponent's checkers.
White rolls 64 with a checker on the bar.
+13-14-15-16-17-18------19-20-21-22-23-24-+ | X O | | O O ^ X | | X O | | O O | | | X | | O | | | X | | O | | | X | X-----4---+ | | |BAR| | | O | | X | | O | | X | | O X | | X | | O X | | X O | | O X | | X O | +12-11-10--9--8--7-------6--5--4--3--2--1-+
If White rolls  with a checker on the bar, he must enter the checker onto Red's four point since Red's six point is not open. If neither of the points is open, the player loses his turn. If a player is able to enter some but not all of his checkers, he must enter as many as he can and then forfeit the remainder of his turn.
After the last of a player's checkers has been entered, any unused numbers on the dice must be played, by moving either the checker that was entered or a different checker.