Chess Opening Theory/1. e4/1...d5/2. exd5/2...Qxd5/3. Nc3/3...Qa5/4. b4/4...Qxb4/5. Nb5

5. Nb5?!

The white knight leaps to b5, eyeing the c7 square and a fork of the black queen and rook. Black can avoid White's tricks with 5...Na6 or 5...Qc5. The most ambitious and popular move however, is 5...Qa5