The Tandem Defense-Offense Tactic
One of checkers' rules is on tandems. Pieces that are adjoining diagonally are in tandem, or standing consecutively. The checkers rule here is that no piece may capture or jump over pieces in tandem, whether it is an ordinary or crowned capturing piece. We can use this rule as a powerful strategy in checkers.
When capturing between two ordinary pieces, a capturing piece should be directly in front of the piece to be captured. The square directly behind it should also be vacant. At times, we find ourselves in a situation in which an enemy is about to capture us and it seems that we have no choice but to let it do so. The capturing piece is supported by another piece right behind it. We cannot retreat because checkers pieces are not allowed to do so. What do we do?
If there is an available ally piece nearby behind our piece the best thing to do is slide it right behind the threatened piece. This makes then stand in tandem. Doing this, what we have is a line of contiguous pieces in tandem our pieces and the enemy pieces standing one after another. In this situation no capturing is possible. We have prevented the attempted capture and we force the opponent to break up the contiguous line by moving either one of the enemy pieces in tandem because it's the enemy's turn to act.
When we foil a capturing attempt using a tandem strategy it is a defensive tandem tactic. We can also use a tandem for an offensive strategy in checkers. When there's a vacant square between our piece and the enemy piece we may slip in an available ally piece close by to the vacant square to form a tandem with our other piece and use it to threaten the enemy piece with.
Or, if an enemy piece, which is a mere square away from our piece, is planning on a forced capture to place us in a disadvantageous situation later, we may use a piece nearby and place it on the vacant square. The tandem formed pre-empts the plan of the enemy and counter threatens the enemy piece. In this case the tandem strategy is used as a defense-offense tool.
Hence, we should often keep pieces in tandem with one another as a strategy in checkers. We should make it a point to ready extra pieces nearby other pieces for a quick shift to this strategy and strengthen our play more.