In the diagrammed chess position from a game played at the ICC, White has just played b7 threatening to Queen with check. Black has a Rook guarding the b8 queening square and two connected passed center pawns at e4 and d4.
First appearances suggest that White is winning this chess game. However it is Black that wins after e3 since he will achieve two passed pawns on the sixth rank after capturing White’s promoted Queen at b8.
Most students of the Royal game are aware of the power of an advancing pawn duo and that a Rook is impotent in preventing the inevitable Queening promotion once both pawns are abreast on the sixth rank. In fact, the strongest chess playing programs such as Houdini and Rybka recognize the immense power of advancing pawn duos and trios and assign value to their presence in a chess position appropriately.