[White "   Caruana - Nakamura, Tata Steel 2013   "]   [Black "Black to play and win"]   [Result "0-1"]   [FEN "3r4/4k3/1p2p1b1/p1b3p1/P1P1N2p/1P3B1P/2K3P1/5R2 b - - 0 1"]   {Black has to exploit the pinned White pieces.   He can do so with the following sacrifice:}   1... g4! 2 hxg4 h3!   {And White is too tied up to do anything}   3 Rd1   (3 gxh3 Rf8 { and  4... Rf4})   Rf8 { and again  4... Rf4.}