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...Qxd7/11. Qh5/11...g6/12. Qe5/12...Kf7/13. Nb5/13...c6/14. Qd4

Black's queen is attacked.

14...Qxd4 is one way to respond to the attack, but Black has no reason to voluntarily haul White's knight out of danger. 14...Rd8 is a better way to accept the exchange of queens for that reason, and is surprisingly popular given that Black has apparently never won a game against a titled player using it! 15.Qxe7 Rxe7 16.Nc3 Nf6 and now White is in no hurry at all and can even justify keeping the king near the action with 17.Rf1 (planning f3) rather than castling.

So assuming that Black is intending to keep the queens on the board, 14...Qe7 is in fact the only good square, because:
 * ...Qe6 walks into a knight fork on c7
 * ...Qc8, ...Qe8 and ...Qf5 walk into a knight fork on d6. That doesn't look like such a problem with the bishop covering d6, but remember that that bishop is part of the delicate mechanism that's going to trap the White queen in the corner after Qxh8. 15.Qxh8 Nf6 16.Nd6+! extracts the queen, thus simply winning an exchange.
 * ...Qg4 falls apart completely after 15.Qxh8 Nf6 16.Nd6+ Ke6 (or ...Ke7) 17.O-O when not only is the knight immune from capture, the f-file is also going to get wrenched open with a quick f3.
 * ...Qd8 means White will grab the rook and then be just in time to save the queen with b3 and Bb2, since the queen trap requires the Black queen to move off the back rank and the a8-rook to be protected and Black can't do both in a single move (15.Qxh8 Nf6 16.b3 Qa5? looks clever, but would be sad trombone time after 17.Bb2 Bg7 18.Nd6+).

14...Qe7
This is White's last chance to grab the h8-rook, otherwise Black is going to shut the door with ...Nf6. Alternatively, White can take advantage of the fact that Black has blocked the e-file with her queen, and go after the e4-pawn with 15.Nc3. This is a better move than 14.Nc3 would have been, because Black can't pin and win the queen with ...Re8 any more.

Möhring Gambit Accepted: 15.Qxh8 Nf6 16.b3
Black springs the trap on the White queen, and White tries to use the bishop to rescue it (diagram left). Now Black has to move the a8-rook to a defended square so the f8-bishop isn't just pinned to it. That means there are two possibilities: 16...Rd8 and 16...Re8. In both cases, White is relying on the tactical detail that 17.Bb2 Bg7 18.Ba3! considerably improves the prospects of the b5-knight, as follows:
 * 16...Re8 17.Bb2 Bg7 18.Ba3 c5 removes the immediate threat. Then 19.Qxe8 Nxe8 (to gain time by hitting the a1-rook) 20.Rd1 Nc7 keeps White a little off-balance as 21.Nxc7 Qxc7 threatens ...Qa5, while after something like 21.O-O Nxb5 22.cxb5 Black can defend the c-pawn with ...Bd4 and then round up one of the b-pawns with the queen. But looking at the bigger picture, White has two rooks and at least one healthy pawn for the queen, and the computers think Black is completely busted.
 * 16...Rd8 17.Bb2 Bg7 18.Ba3 Qd7 19.Nd6+ Ke6 (not 19...Qxd6 20.Qxg7) 20.Qxd8 Qxd8 21.Nxb7 Qc7 22.Nc5+ followed by Bb2. White is consolidating while now having three pawns and two rooks for the queen (though she should beware of blindly castling kingside and getting hit with ...Ng4, discovering an attack by the bishop and threatening mate on h2!)

Ivanov's Retreat: 15.Nc3 Nf6
This (see diagram right) is the sober-minded option, forcing Black to spend time defending e4 and ensuring that both players keep the same number of queens on the board, and it scores a bit better than accepting the rook. Now:
 * Ivanov's original idea was 16.Qe3, eyeing the advance of the d- and f-pawns, but Black always has the option of parking a rook on d3 via d8 (forcing White into a further retreat to e2) which White will find it awkward to play around.
 * 16.O-O simply threatens to add another piece to the attack on e4. 16...Rd8 can now be met by an active move like 17.Qb6, and if Black insists on playing 17...Rd3 then White can ignore it completely and go for a touchdown on the a-file with 18.a4!
 * White may have an interesting forcing option in 16.c5 followed by Qc4+ and b4.
 * 16...Qxc5 is met by Qxf6 when White gets to remove the queens along with the awkward e4-pawn. White still has some unravelling to do in the resulting endgame - but two pawns is two pawns.
 * 16...Rd8 17.Qc4+ and now Black has nothing better than to let the queens come off with 17...Qe6 18.Qxe6+ Kxe6, because g7 will be an uncomfortable square for the king after b4 and Bb2, while retreating to the back rank would interfere with the development of the h8-rook.