King's Gambit Declined

2...d6

This is one way to decline the King's Gambit. This can arise from many different positions, but this transposition to the King's Gmabit Declined is most common. This is somewhat sounder than the King's Gambit Declined, Classical Variation, as in the Classical Variation, white can chase the bishop out of c5 and put more pressure on e5, especially with Nf3. Here, on the other hand, if white plays 3. Nf3?!, then black plays 3...exf4! transposing to the King's Gambit Accepted, Fischer Defense. This is similarly true with with 3. Nc3!?, but in this case, white gets a lot more compensation for the pawn compared to 3. Nf3. In fact, the best move here is 3. d3!, defending the pawn on f4 and blocking all transpositions to the King's Gambit Accepted. However, white had to make a concession for this: block his light-squared bishop. Nevertheless, 3.d3 leads to equality with best play. Note: If white plays 3. Bc4 (to not block the bishop), 3...exf4! also works.