Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...Nb4

A dubious sideline that sets a trap for White. By removing their knight, Black removes a defender of the e5 pawn and apparently leaves it hanging?

Since the Spanish opening revolves around creating and defending threats to the e-pawns, White is especially primed to take it. However, 4. Nxe5? is a mistake: after 4...Qg5! Black's queen forks the knight and the g2 pawn. The best line for White is then to give up the knight and castle, 5. O-O Qxe5, otherwise e.g. 5. d4? [defending the knight] Qxg2! and White loses back the pawn and then some.

The manoeuvre, undefending e5 and hoping for Nxe5 followed by ...Qg5!, is the same idea as in the Blackburne shilling gambit in the Italian opening.

Therefore, White must postpone grabbing the pawn. Once White has castled, 4. O-O, g2 is defended and so White threatens to take on e5 for real. Then, a common idea for Black is to play with tempo ...c6 and ...d5. After 4. O-O c6 5. Bc4 d5 6. exd5 cxd5 7. Bb5+ Bd7 8. Bxd7+ Qxd7 9. Nxe5±, White has the pawn and is ahead.

The earliest record of this trap comes from Frank Marshall (1877―1944), who played it in his 3-game match with Johannes Esser in 1911.^[1] Esser avoided the trap.

An audacious amateur tried the line against Garry Kasparov in a simul organised by ChessFriends.^[2]

For explanation of theory tables, see theory table and for notation, see algebraic notation.

1. e4 e5 2. Nf3 Nc6 3. Bb5 Nb4

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