Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...f5/4. Nc3/4...fxe4/5. Nxe4/5...d5/6. Nxe5/6...dxe4/7. Nxc6/7...Qd5/8. c4/8...Qd6/9. Nxa7/9...Bd7/10. Bxd7/10...Qxd7

Ruy Lopez, Schliemann Defence

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

Common moves:
11. Qh5+ - Main Line
11. Nb5 - Retreat Variation

The main line here is 11. Qh5+. White has the bread and butter of two extra pawns, and wants the jam as well (stopping Black from castling). Black can offer an exchange sacrifice in response, but White shouldn't accept it; the realisation that White isn't obliged to accept it was responsible for 11. Qh5+ taking over as the main line from:

11. Nb5, which seems like it should be enough for a solid advantage. Two pawns are two pawns! But it actually scores rather badly for White. There's a caveat, as there always is with opening statistics: if top players know 11.Qh5+ is playable but weaker players aren't in on the secret, then 11.Nb5 will end up being played by weaker players, and weaker players are more likely to lose.