The blockade is a chess tactic used to block your opponent from pushing pawns up the board. The pawn’s true value comes from the threat of promoting to a more powerful piece. When one side gets an isolated or a passed pawn, it’s common for them to push that pawn up the board. This forces the opponent to respond and play defensively.
The best piece to block your opponent’s pawns with is the knight. It can easily hop over material to reach the optimal square. It also is on the weaker side compared to rooks, queens, and in many cases, bishops. For this reason, if you see your opponent pushing forward with a pawn, try to maneuver you knight to block the pawn from advancing.
To learn more about blockades and see some examples, check out the video below.