Checkers is an ancient and fun game, where players must capture or stop the movement of all of their opponent's pieces. Getting one of the checkers to the other side of the board makes it a "king," meaning it can jump forward and backwards. Single checkers can still jump over kings, just as they can jump over single checkers.
No Backwards Movement
Single checkers cannot move backwards under any circumstance. This is true even if there is a king behind them. The single checker is in fact in great danger of being taken when a king is lurking behind it. Players must try to get their checker defended from these attacks by placing a checker in front of it and creating a blockade or by moving forward towards becoming a king. If anybody tries to move a single checker backwards to jump over a king, this is an illegal move. It must be taken back immediately, and the player must make another move to replace it. There is no penalty for making an illegal move, besides the move being taken away from the player and any kings improperly taken by the move being placed back in their original position.
Players must always take any jump that they can when it is available. This is no different when a single checker jumps a king. The single checker must make any jump that presents itself during the game. This is a tactic with the king that players can use to whittle down their opponents' checkers. Placing a king in front of a single checker when other jumps are available will make the king look very appealing. However, having a well-defended checker behind the jumped king will make the opponent lose their single checker. This can be a downside to the opponent with a king, however. He is just as obliged to jump over a single checker, and using a well-defended sacrifice can help eliminate an opponent's king easily. Take advantage of this rule at all times.
A single checker can make multiple jumps over as many kings as it can. As long as it is possible to continue making jumps, a single checker can continue jumping. However, a single checker cannot make a backwards jump on the same turn it is made a king. For example: a single checker double-jumps to the last row, and it becomes a king. One of his opponent's kings is in jumping position when the checker is made king. Unfortunately for the newly kinged checker, it cannot make this backwards jump. Becoming a king is considered the end of its turn. However, kings that land on the other end of the board can make this jump.
No Self Jumping
A single checker cannot jump over any of its own checkers. This is also true of kings. For example, a player has a checker in a double-jump position that can take one of his opponent's kings across the board. However, the first checker in the double jump is one of his own. He cannot jump his own checker to try to take the king. This move is illegal and will be reset immediately if it is tried.