The following game quickly reaches a position which has a score of 72% for White in The Database. There is a rating difference of about 600 points between the players - favoring White.
You would think - especially in a blitz game - that the first player would have an overwhelming advantage. Indeed, he checkmates his opponent in 16 moves.
But - if you turn the game over to Stockfish 8 on its "blunder check" setting, the story quickly becomes more complicated.
Please note, I mean no offense to the players. None of us are computers. I use Stockfish 8 to show just how deep apparent shallow waters are... And to show how a checkmate attack can be either pursued or avoided.
lcuartas - diegogs
10 0 blitz, FICS, 2016
1.e4 Nc6 2.Nf3 e5 3.Bc4 Na5
Anyone who plays the Jerome Gambit has to be prepared for this offside move. I usually recommend the typical Jerome response, although the alternative, 4.Nxe5, is fine, too.
4.Bxf7+ Kxf7 5.Nxe5+ Ke6
White has sacrificed a piece for two pawns, and the computer gives him a small advantage.
6.Qg4+ Kxe5 7.d4+ Kd6
Black can afford to take the second piece, as scary as it seems, but he would choke on the d-pawn: 7...Kxd4 8.Be3+ Ke5 9.Qf5+ Kd6 10.Bc5+ Kc6 11.Qd5+ Kb5 12.Nc3+ Ka6 13.Qd3+ Nc4 14.Qxc4+ b5 15.Qxb5 checkmate.
You can tell that Black's King is in danger, but working it out during the game can be quite a challenge - especially with the clock ticking.
8.e5+ Kd5
This is an error. Instead, the computer recommends a convoluted line to a surprising equality: 8...Kc6 9.d5+ Kb6 10.Be3+ c5 11.d6 Nh6 12.Qe4 Bxd6 13.exd6 Re8 14.Qd5 Qh4 15.Qxc5+ Ka6 16.Nc3 b6 17.Qb5+ Kb7 18.O-O-O Qc4 19.Qxc4 Nxc4 20.Bxh6 gxh6 21.Rd4 Na5 22.Rf4 Re6 23.Rd1 a6 24.b3.
I don't expect club level humans to be able to play that way. Note, though, the White pawn advance to d6 to keep the c7 square covered, to avoid allowing Black's King to escape. Also, that White seems to be scampering to keep the game even and avoid falling behind.
9.c4+
What is going on? White continues to harass the enemy King, overlooking a chance to acquire the enemy Queen: 9.Qf3+ Ke6 10.d5+ Ke7 11.Bg5+ Ke8 12.Bxd8 b6 13.e6 Nf6 14.Bxf6 gxf6 15.d6 Bxd6 16.Qxa8 Kd8 17.exd7 Kxd7 18.O-O Re8 19.Qf3 Ba6 20.Rd1 Kc8 21.Qa8+ Kd7 22.Qd5 Kc8 23.Nc3 Kb8 24.Ne4 Rd8. Nice cooperation between pawns and pieces.
9...Nxc4
Now the pendulum has swung again. The King needed to move, it wasn't time for a pawn grab: 9...Kc6 10.Qd1 a6 11.c5 d5 12.Qa4+ b5 13.Qxa5 Kb7 14.a4 Bd7 15.Be3 Ne7 16.Qd2 Nf5 17.O-O Be7 18.Nc3 Bc6 19.axb5 axb5 20.Na2 Qe8 21.Nb4 Qg6 22.g3 Rxa1 23.Rxa1 Ra8 24.Rxa8 Kxa8 25.Qd3 and Black has an edge, as White has not been able to corral the enemy monarch.
10.Nc3+ Kc6 11.d5+ Kc5
Those pesky "Jerome pawns"! The King is now in a mating net.
12.a3
Planning to add the b-pawn to the mix, but it could have been added directly, as capturing it would allow the White Rook into the game, too: 12.b4+ Kb6 13.Qxc4 c6 14.d6 Bxd6 15.exd6 Qe8+ 16.Be3+ Qxe3+ 17.fxe3 a5 18.Qc5+ Ka6 19.Qxa5 checkmate.
12...Nxe5
This should lead to immediate disaster, as opposed to longer-term disaster.
13.b4+
As planned. Also 13.Qb4#
13...Kb6
Chess is not fair. Black continues along the path to destruction, while he had a chance to escape it: 13...Kd6 14.Qe2 c6 15.Bf4 Kc7 16.Bxe5+ d6 17.Rc1 Qg5 18.Nb5+ Kd8 19.f4 Qg4 20.Nxd6 Bxd6 21.Qxg4 Bxg4 22.Bxd6 cxd5 23.Bc7+ Ke8 24.Be5 Nf6 25.O-O Rc8 26.h3 Be6 27.Rxc8+ Bxc8 28.Rc1 Kd8 29.Bc7+ with advantage to Black.
14.Be3+
A perfectly reasonable move, adding a piece to the attack. The soulless comuter says that the move leads to a Black advantage, however, and prefers: 14.Na4+ Kb5 15.Qe2+ Nc4 16.Nc3+ Kb6 17.Qxc4 Qe7+ 18.Be3+ c5 19.d6 Qxd6 20.bxc5+ Kc7 21.cxd6+ Kd8 22.Nb5 Nf6 23.Bxa7 Rxa7 24.Nxa7 Bxd6 25.Qxc8+ Ke7 26.Qxh8 Kf7 27.O-O Bc5 28.Nb5 b6 29.Rfe1 Kg6 White is winning.
14...Ka6
Of course. Still, the silicon beast prefers: 14...c5 15.dxc6+ Kc7 16.Nb5+ Kb8 17.c7+ Qxc7 18.Qd4 Nc6 19.Bf4 d6 20.Qe3 Qb6 21.Qg3 Bg4 22.Nxd6 g5 23.Bxg5 Qc7 24.Nf7 Qxg3 25.hxg3 Bg7 26.Rc1 a6 27.Nxh8 Bxh8 28.Rxh7 Bb2 29.Bf4+ Kc8 30.Rc2 when Black is better.
15.b5+ Ka5 16.Qa4 checkmate
There you have it. The result is exactly as expected. Another example of a bold, sacrificial attack winning.
How often do we wander through life, feeling propelled, overlooking alternatives we are not even aware are there?
Chess is a peek at the multi-verse.
