Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nd4

= Blackburne Shilling Gambit =

3...Nd4
Black violates an opening principle by again moving his knight. It may be tempting for White to take the now unprotected pawn with 4. Nxe5? but after 4...Qg5, White is in trouble (though 5. Bxf7+ remains playable). To maintain an advantage, White can play /4. Nxd4/, /4. c3/ or /4. O-O/.

Theory table
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'''1. e4 e5 2. Nf3 Nc6 3. Bc4 Nd4'''