Block (chess)

A block is a defensive tactic in chess in response to an attack, whereby a piece is interposed between the attacking piece and the piece being attacked. Blocking is not an option when the attacking piece is directly adjacent to the piece it is attacking, or when the attacking piece is a knight (because knights jump).

Blocking a check is done by moving a piece to a square in line in between the checking piece and the checked king. This will only work if the checking piece is a queen, rook or bishop and there is at least one empty square in the line between this checking piece and the checked king. Note that the blocking piece is then pinned to the king by the attacking piece, until it is unpinned.

Blocking and initiative

When the attack cannot be ignored, the attacking player has the initiative. The defending player may be able to acquire the initiative by blocking and attacking at the same time, by attacking an undefended attacker with the blocking piece, with a discovered attack, or when the block is also a check or a cross-check.

See also

• Blockade
• Chess tactic
• Interference
• Prophylaxis

References