Chess Pins
Chess has two types of pins, absolute when a piece is pinned to the King, and soft (or relative) when a piece is pinned to something of higher value, such as a Queen or Rook behind a Knight. Soft pins can be broken. On the previous move, Black moved Bg4, creating a pin on the Knight and Queen. White to move:
FEN rn1qkb1r/pp2pppp/2p2n2/8/2B3b1/2N2N2/PPPP1PPP/R1BQ1RK1 w kq - 2 7
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A clever response is Ne5, exposing the Queen to the attacking Bishop. Black must not take the Queen, as otherwise White wins: Bxf7# checkmate. Instead, Black must resolve the mate-in-1 threat, probably by retreating the g4 Bishop to e7. This allows White to exchange Bishops, and leaves Black with double isolated pawns on the e-file.