What is a Skewer?

A skewer happens when one of your pieces attacks a more valuable piece that is standing in front of a less valuable piece. Because the stronger piece is under attack, it must move out of the way. When it moves, the piece behind it is left unprotected and can be captured. It is like pushing one piece aside to reach another.

Definition:

Skewers are powerful because they force your opponent to react immediately. For example, if your queen attacks the king and there is a rook behind it, the king must move out of check. Once the king moves, the rook behind it can be captured. Learning to line up pieces on the same row, column, or diagonal will help you spot skewer opportunities during a game.

Why skewers are powerful?