Countergambit

This page explains commonly used terms in chess in alphabetical order. Some of these have their own pages, like fork and pin. For a list of unorthodox chess pieces, see Fairy chess piece; for a list of terms specific to chess problems, see Glossary of chess problems; for a list of chess-related games, see List of chess variants.

As a defensive tactic the X-ray occurs when one piece is defended by another piece, even though an enemy piece stands between the two.

Bibliography

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Wikipedia