notyetagm: Position after 29 ...  c7-f4!  :
click for larger viewTactical factors pertinent to this winning tactical shot by Black (Carlsson): <1) DO NOT LINE UP YOUR PIECES!> White d2-queen + White c1-rook(!): A diagonal alignment involving a rook simply provokes a <PIN/SKEWER/FORK> <2) OVERWORKED KNIGHT PAWN> White g3-pawn is lined up with White g1-king (Case #3): White g3-pawn must <BLOCK> g-file to White g1-king while <DEFENDING> both f4-,h4-squares <3) UNDEFENDED KINGSIDE> White's minor pieces (White a3-bishop, White b3-knight) far away from kingside: Kingside undefended provokes an attack <4) BISHOPS ON OPEN DIAGONALS> Black c7-,d7-bishops may not look like they are doing much on QB2, Q2. But bishops on open diagonals are always well placed for whatever may come. Bishopd on open diagonals <LURK>, just wainting for the right moment to sprinh into action (29 ... c7-f4!). 1  e2-d2? c7-f4! <skewer> 2 g3xf4?? <demolition of pawn structure> c6-g6+ 3  g1-h1  f5-h5 Note how the light-squared Black d7-bishop denies the h3-square to the White king so that White
cannot play his king to h3 to support the crucial h4-pawn,h4-square. This bishop is usefully placed
even though it is only on Q2 because it is on an open diagonal. | 
