An x-ray is when a long-range piece exerts its influence through an enemy piece along a rank, file, or diagonal, attacking or defending what lies beyond it.
A rook, bishop, or queen can ‘see through’ an enemy piece in the sense that, once that piece moves or is captured, the line opens onto whatever stands behind it. The x-ray is the latent pressure along that line.
It works two ways. Offensively, you attack a target shielded by another piece, so removing the shield wins it. Defensively, your piece guards a square or friendly piece through an enemy piece in between.
An x-ray is the family that skewers and some pins belong to: the common thread is one piece’s power reaching past another on the same line. Looking down every open line for hidden targets behind pieces is a core tactical habit.
A skewer forces a valuable piece to move and wins the lesser one behind it. An x-ray is the broader idea of a piece acting through another along a line, for attack or defence.
Yes. A piece can defend a square or a friendly piece through an enemy piece standing in between, so the defence still holds if the intervening piece is removed.
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