61 ( +1 | -1 ) The Najdorf Poisoned...Pawn Variation happens only when white gives his b2 pawn. This is obvious.
This was a great favourite defense of Bobby Fischer. White develops very quickly but black has an extra pawn (and quoting Silman: "Maybe it's ugly, but is mine...:)"), which is in fact a sort of life insurance: If black can stop the white's initiative and simplify the position, the extra pawn begins to weight. Fischer was a master of the defense (a great admirer of Steinitz) and a super endgame player, so he feels like a fish in the water in this fascinating variation.
18 ( +1 | -1 ) Rb1 appears to do nothing except tie the rook down to a defensive task on an awkward square. If you want to keep the pawn, Nb3, blocking the queen's path to the pawn, is much better.
18 ( +1 | -1 ) poisonIs it poison if you don't take it? Does a falling tree make a noise if no one is there to hear it? Can God make two mountains without an intervening valley? How many angels can stand on the head of a pin?