The Evans Gambit, one of the most topical chess openings of the last century, experienced a sharp decline in popularity when ways were found for Black to equalize easily and avoid the dangerous attacking lines that had made it such a feared weapon. However, it has never really disappeared completely, and both Bobby Fischer and Garry Kasparov have wheeled out this gambit as a nasty surprise for unprepared opponents.

The opening moves are:

1.e4 e5
2.Nf3 Nc6
3.Bc4 Bc5
So far this is a normal king's pawn opening continuation, and with the move 4.c3 White could initiate the Giuoco Piano, another ancient opening whose heyday has passed. However, with 4.b4, the first move of the Evans Gambit, White sacrifices a pawn in order to play c2-c3 with gain of tempo by attacking the Black bishop.
4.b4 Bxb4 (Black can decline the offered pawn with 4...Bb6, accepting a slight loss of space on the queenside)
5.c3 Be7 (alternative moves here are 5...Ba5 and 5...Bc5)
6.d4

It may seem foolhardy to give up a whole pawn just to gain a single move in the opening, but in open king's pawn games a single move can mean the difference between victory and humiliation. If Black plays passively, he can lose very quickly. Therefore his best plan is to return the pawn immediately and attack White's well-placed bishop with 6...Na5 7.Nxe5 Nxc4 8.Nxc4 d5, which until recently was thought to guarantee at least a level game.

Fischer played the Evans Gambit against top grandmaster Reuben Fine in New York in 1963, producing a 17-move brilliancy when Fine grabbed one too many pawns instead of trying to shore up his defenses. The score of that game is given below.

More recently, Garry Kasparov sparked a mini-renaissance in the Evans Gambit when he played a new move against Black's main defensive strategy (which begins 6...d5 as shown above) - one which renewed White's attacking chances and forced a re-evaluation of the entire line. This was all the more remarkable because, whereas Fischer's game against Fine was casual, Kasparov played his move against Viswanathan Anand, one of the top 5 players in the world, in a serious tournament. Bemused grandmasters found themselves studying 100-year-old theoretical lines in a gambit which they had thought consigned to the dustbin of chess history. Kasparov's novelty and the score of the game against Anand are also given in the endnotes below.

This kind of re-evaluation of old chess openings is occurring frequently in modern chess, with creative players returning to discarded lines in an effort to find new and fertile grounds for innovation. Chess opening theory has become so unwieldy and vast (more books have been written on chess than all other sports combined) that some players, including Bobby Fischer, have even suggested altering the initial setup of the pieces, in order to make obsolete the requirement on all top grandmasters to memorize huge quantities of opening variations. For details of these suggestions, see Fischer Random Chess.


Notes

Bobby Fischer - Reuben Fine, New York, 1963 (Evans Gambit)
1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.b4 Bxb4 5.c3 Ba5 6.d4 exd4 7.0-0 dxc3 8.Qb3 Qe7 9.Nxc3 Nf6 10.Nd5 Nxd5 11.exd5 Ne5 12.Nxe5 Qxe5 13.Bb2 Qg5 14.h4 Qxh4 15.Bxg7 Rg8 16.Rfe1+ Kd8 17.Qg3!! 1-0 (White wins)

Kasparov's innovation in the Evans Gambit:
1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.b4 Bxb4 5.c3 Be7 6.d4 Na5 7.Be2 exd4 8.Qxd4!
The Queen capture had never been considered, and gives Black all kinds of problems with developing his remaining pieces. The game continued:
8...Nf6 9.e5 Nc6 10.Qh4 Nd5 11.Qg3 g6 12.0-0 Nb6 13.c4 d6 14.Rd1 Nd7 15.Bh6 Ncxe5 16.Nxe5 Nxe5 17.Nc3 f6 18.c5 Nf7 19.cxd6 cxd6 20.Qe3 Nxh6 21.Qxh6 Bf8 22.Qe3+ Kf7 23.Nd5 Be6 24.Nf4 Qe7 25.Re1 1-0