Jerome Gambit: Looks Simple, But It Is Not

In the following Jerome Gambit (1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+) game, the same player from the previous post again tries his best against the "annoying" or "silicon" defense. The line the players explore looks simple, but it is not. 

Anonymous - Anonymous
1 move / 3 days, Chess.com, 2020

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ 

4...Kxf7 5.Nxe5+ Nxe5 6.Qh5+ Ke6 

7.f4 d6 8.fxe5 dxe5 

White has one pawn for his sacrificed piece.

Black's King is annoyingly safe in the center, but White will try batting him around a bit.

This defense was seen as early as the 1993 match between Micah Fisher-Kirshner and the computer program KnightStalker (an early version of ChessBase's Fritz, marketed in the US).

9.Qh3+ Kd6 10.Qd3+ Ke7 11.Qg3 Kf6 

Up until Black's last move, we have been following games where Black was played by computer programs Comet B50, Demon 1.0, Fritz 8, Junior 7, Knightstalker, La Dame Blanche 2.0c, Rybka (v.1 and 2.3.2a), and Zarkov 4.7. None of them chose the move in the game.

What's the problem with the move? Because Black does not want to give up a pawn (11...Kf7 12.Qxe5) he allows the Rook to come to f1, with a check that requires another King move.

12.Rf1+ Ke6 

What is going on?

Well, it's probably not a good idea for White to go pawn-grabbing with 13.Qxg7, as Black not only has the development 13...Nf6, with an even game, he has the sharp riposte 13...Qh4+, when 14.Kd1 Qh5+ 15.Ke1 Qg6 forces the exchange of Queens, and Black's development, activity and Bishop pair give him a clear advantage.

Because computers almost always see White as worse in the Jerome Gambit opening, they constantly look for drawing lines as "best", and, here, Komodo 10 offers one: 13.Qb3+ Kd7 14.Qb5+ Kd6 15.d4 Qh4+ (necessary to move the Queen, otherwise 15...Bxd4 16.Qd5+ Ke7 17.Rf7+ wins it) 16.Rf2 Bxd4 17.Qd5+ Ke7 18.Qf7+ Kd6 19.Qd5+, etc.

So, it's not surprising that White, instead, gives the enemy King another kick, even if it's not objectively the best move.

13.Qg4+ Kd6 14.Qxg7

This capture has its risks. The Queen would probably be safer on g3, but White is not seeking out safety.

14...Ne7 

Protecting the safe Rook. However, after 14...Qh4+ 15.Kd1 Bg4+ White's position would be a mess. 

15.d4 Bxd4 16.c3 

White is still playing with only a couple of pieces, but Komodo 10 rates him as having a slight edge, especially after the recommended return of a piece with 16...Ng6. The reasonable alternative, which Black plays, leads to a difficult position for the defender.

16...Bb6 17.Bg5 

You can almost hear White saying "Gotcha!"

17...Re8 18.Na3 

This Knight means trouble.

18...Be6 

Black needed to try 18...Bg4, but 19.Nc4+ Kc6 (other moves are worse) 20.Qf7 would force him to return a couple of pieces, i.e. 20...Bf2+ 21.Rxf2 b6 22.Nxe5+ Kb7 23.Nxg4.

White's next move settles everything.

19.O-O-O+ Kc6 20.Rxd8 Raxd8 21.Qxe5 Bxa2 22.Qb5+ Kd6 23.Rf6+ Be6 24.e5 checkmate

Different Analysts, Same Outcome

Torneo tematico GaJero00-A  2009

                      1 2 3 4 5 6 7 8
1 Rybka 2.3.2a (2 CPU) ** 11 01 01 1½ 11 11 11 11.5/14
2 WB Nimzo 2000b       00 ** 01 11 1½ 11 ½1 11 10.0/14
3 SOS 5.1              10 10 ** 00 11 11 11 ½1 9.5/14
4 Comet B48            10 00 11 ** 10 01 11 11 9.0/14
5 Zarkov 4.70          0½ 0½ 00 01 ** 1½ 01 11 6.5/14
6 DrunkenMaster 1.2 00 00 00 10 0½ ** 10 11 4.5/14
7 La Dame Blanche 2.0c 00 ½0 00 00 10 01 ** 01 3.5/14
8 Demon 1.0            00 00 ½0 00 00 00 10 ** 1.5/14

The following game from the Jerome Gambit thematic chess tournament presented at the Scacchi64.com website provides a framework for how a number of computer chess programs address a particular opening line. (I have been guided in my own assessments by Stockfish 7.)

La Dame Blanche 2.0c - Comet B48
Torneo tematico GaJero00-A, 2009

 1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ 

4...Kxf7 5.O-O Nf6 6.Nxe5+ Nxe5 7.d4 Qe7

A bit better is 7... Bxd4 8. Qxd4 d6 (8...Nc6 9. Qc4+ [9. Qa4 Qe7 10.Nc3 Qb4 11.Qxb4 Nxb4 12.e5 Nxc2 13.Rb1 Ne8 14.Bf4 c5 15.h3 b6 16.Rbc1 Nd4 17.Rcd1 Ba6 18.Rfe1 Kg6 19.Rd2 Nc7 20.Be3 Nce6 21.a3 Rhf8 22.b4 Rf5 23.bxc5 bxc5 24.f4 Nxf4 25.Bxf4 Rxf4 26.Nd5 Rff8 27.Nc7 Bb5 28.Rxd4 cxd4 29.Nxb5 Rf4 30.e6 d3 31.Rd1 dxe6 32.Rxd3 Kf6 33.Kh2 a5 34.Kg3 g5 35.Rd7 Rb8 36.Nd6 Rb3+ 37.Kh2 Kg6 38.Rc7 Rxa3 39.Nc4 Ra2 40.Ne5+ Kf5 41.Nd3 Rd4 42.Rf7+ Ke4 43.Nf2+ Kd5 44.Rd7+ Kc4 45.Rc7+ Kb5 46.Rf7 Rdd2 47.Kg1 Rxf2 48.Rxf2 Rxf2 49.Kxf2 Kc4 50.Ke1 Kc3 51.Kd1 Kb2 52.Ke2 Kc2 53.Kf3 White resigned, Demon 1.0 - Rybka 2.3.2a, Torneo tematico GaJero00-A, 2009] 9...d5 10.exd5 Qxd5 11.Qxd5+ Nxd5 12.c4 Ndb4 13.Nc3 Bf5 14.Bf4 Nd3 15.Nd5 Nxb2 16.Nxc7 Rac8 17.Nb5 Nxc4 18.Rac1 a6 19.Nc7 N6e5 20.h3 Rxc7 21.Bxe5 Rc6 22.Bf4 Re8 23.Rc3 Re4 24.Rf3 Re2 25.a3 Be4 26.Rc3 Nb2 27.Rg3 Rcc2 28.Be3 Nc4 29.Bd4 g6 30.Kh1 Rcd2 31.Ba7 b6 32.Kg1 Ra2 33.Rc1 Bd5 34.Rd1 Ke6 35.Kh1 Rxf2 36.Re1+ Kd7 37.Rg1 Kc6 38.Rg5 Ne3 39.Rc1+ Kb7 40.Bxb6 Kxb6 41.Rb1+ Kc5 White resigned, La Dame Blanche 2.0c - Rybka 2.3.2a, Torneo tematico GaJero00-A, 2009) 9.f4 Nc6 10.Qd3 Re8 11.Qc4+ (11.Nc3 Kg8 12.f5 Ne5 13.Qg3 Nf7 14.Re1 b6 15.Bd2 Bb7 16.Qf4 Re5 17.Qf3 Qe8 18.Bf4 Bxe4 19.Nxe4 Rxe4 20.Rxe4 Qxe4 21.Qxe4 Nxe4 22.Re1 Re8 23.h4 Nf6 24.Rxe8+ Nxe8 25.Kf2 Ne5 26.Bc1 Nf6 27.Ke2 Kf7 28.Bg5 Nd5 29.h5 h6 30.Bd8 c5 31.b3 Nc6 32.c4 Nxd8 33.cxd5 Kf6 34.Kd3 Kxf5 35.Kc4 Ke4 36.Kb5 Kxd5 37.g3 a6+ 38.Kxb6 c4 39.bxc4+ Kxc4 40.Kc7 d5 41.Kxd8 Kd3 42.g4 Ke3 43.a4  White resigned, La Dame Blanche 2.0c - WB Nimzo 2000b,Torneo tematico GaJero00-A, 2009) 11...Be6 12.Qa4 Kg8 13.Nc3 a6 14.f5 Bf7 15.Qa3 Nd4 16.Rb1 Qd7 17.Rf2 Nxe4 18.Nxe4 Rxe4 19.Be3 Nxf5 20.Bg5 h6 21.Bd2 Nd4 22.Qd3 Rae8 23.Rbf1 Ne2+ 24.Kh1 Rd4 25.Qf3 Bd5 26.Qe3 Rxe3 27.Bxe3 Re4 28.Rxe2 Bc4 29.Ra1 Bxe2 30.Bd2 Qf5 31.Re1 White resigned, La Dame Blanche 2.0c - Zarkov 4.70,Torneo tematico GaJero00-A, 2009.

Also a bit better than the text is 7...d5 8.dxe5 Nxe4 9.Be3 Rf8 (9...Bxe3 10.fxe3+ Kg8 11.Nc3 Nxc3 12.bxc3 Be6 13.Qd4 Rc8 14.Qxa7 Qg5 15.Qd4 c6 16.Rf3 h5 17.Rb1 b5 18.h4 Qg6 19.Rb2 Re8 20.Rf2 Ra8 21.Qb4 Rh6 22.Qf4 Qe8 23.Rd2 Rg6 24.Rd4 Qe7 25.Rd1 Rf8 26.Qb4 c5 27.Qxb5 Rxg2+ 28.Kxg2 Qxh4 29.Qe2 Bg4 30.Rh1 Qg5 31.Qf1 Be2+ 32.Kh2 White resigned, Demon 1.0 - WB Nimzo 2000b, Torneo tematico GaJero00-A, 2009) 10.Bxc5 Nxc5 11.b4 Ne6 12.Nc3 c6 13.Qc1 Kg8 14.Ne2 Qb6 15.a3 Rf5 16.Qb2 Qc7 17.f4 g5 18.g4 Rxf4 19.Nxf4 Nxf4 20.Rae1 Bxg4 21.Kh1 Re8 22.Rxf4 gxf4 23.Rg1 h5 24.h3 Qh7 25.c4 Kf7 26.hxg4 hxg4+ 27.Qh2 Qe4+ 28.Rg2 Kg7 29.c5 g3 30.b5 Rh8 31.Qxh8+ Kxh8 32.bxc6 White resigned, Demon 1.0 - Zarkov 4.70, Torneo tematico GaJero00-A, 2009 

8.dxc5 Qxc5 9.Nc3

Or, 9.Be3 Qb4 10.Bd4 Nc6 11.Bxf6 gxf6 12.Qd5+ Kg7 13.Nc3 Qxb2 14.Qd3 Ne5 15.Qd2 Qb4 16.Rab1 Qc5 17.Rb5 Qc6 18.Qe3 d6 19.f4 Ng6 20.f5 Ne5 21.Rf4 b6 22.Qg3+ Kf7 23.Rd5 Bb7 24.Qe3 Rag8 25.h3 Rg7 26.Rd4 Rhg8 27.g4 h5 28.Kf1 Ba6+ 29.Kf2 hxg4 30.h4 Rh8 31.Ra4 Rxh4 32.Rxa6 g3+ 33.Kg1 Rxf4 34.Qxf4 Qc5+ 35.Kg2 Qxc3 36.Ra3 White resigned, Demon 1.0 - Comet B48,Torneo tematico GaJero00-A, 2009 

9...d6

White has only a pawn for its sacrificed piece, but has some play against Black's uncastled King.

10.Bg5 Be6 11.Bxf6 gxf6 12.Qh5+ Ke7 13.Rab1 

This is a mysterious Rook move, indeed. Perhaps better was 13.Kh1, preparing 14.f4.

13...Rag8 14.Rfe1 Rg4 15.Qh3 Rhg8 16.Kh1 Rxg2

Removing White's King's protection.

17.Qxg2 Rxg2 18.Kxg2 Ng4 19.Re2 Qe5 20.f4 Qxf4 21.Kg1 Kd7 22.Rd1 Bc4 23.Red2 Qg5 24.Kh1 Qc5

White has no counterplay and soon will be vanquished.

25.Na4 Qe3 26.Nc3 Bf1 27.Nd5 Qf3+ 28.Kg1 Be2 29.Nxf6+ Nxf6 30.Rd3 Bxd3 31.Rxd3 White resigned

What Can We Learn From the Robots?

Torneo tematico GaJero00-A  2009

                      1 2 3 4 5 6 7 8
1 Rybka 2.3.2a (2 CPU) ** 11 01 01 1½ 11 11 11 11.5/14
2 WB Nimzo 2000b       00 ** 01 11 1½ 11 ½1 11 10.0/14
3 SOS 5.1              10 10 ** 00 11 11 11 ½1 9.5/14
4 Comet B48            10 00 11 ** 10 01 11 11 9.0/14
5 Zarkov 4.70          0½ 0½ 00 01 ** 1½ 01 11 6.5/14
6 DrunkenMaster 1.2 00 00 00 10 0½ ** 10 11 4.5/14
7 La Dame Blanche 2.0c 00 ½0 00 00 10 01 ** 01 3.5/14
8 Demon 1.0            00 00 ½0 00 00 00 10 ** 1.5/14


The crosstable above is for the Jerome Gambit thematic chess tournament presented at the Scacchi64.com website, referred to in a couple of earlier posts (see "The Macbeth Attack" and "From the Scacchi64.com Jerome Gambit Thematic").

It is not surprising that the tournament leader, Rybka, had the best score with the Jerome Gambit, with 4 wins and a draw. (It climbed to the top by beating the Jerome 7-0. I know how that goes: see "Overrated!")

The next finishers - WB Nimzo, SOS and Comet - all had 3 wins. They were followed in the standings by Zarkov and DrunkenMaster, each with 1 Jerome Gambit win.

Of note, half of the games featured the "classical" 5.Nxe5+, with White scoring 34% (versus 54% in The Database) while half had the "modern" 5.0-0, with White scoring 29% (versus 38% in The Database). 

Interestingly, Rybka played 5.0-0 in all 7 of its games with White and scored 64%, WBNimzo and Comet, the #2 and #4 finishers, all played 5.Nxe5, while 3rd place finisher SOS stuck with 5.0-0.

Perhaps the most "psychological" opening move played in a winning effort - and here I mean the kind of move that would emotionally effect an opponent, if the opponent, indeed, were succeptible to feeling emotions - came in the following game.

DrunkenMaster 1.2 - La Dame Blanche 2.0c
Torneo tematico GaJero00-A, 2009

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ 

4...Kxf7 5.Nxe5+ Nxe5 6.Qh5+ Ke6 7.f4 d6

The "Silicon Defense", very popular with computers.

8.fxe5 dxe5 9.Qh3+ Ke7 10.Qg3 Qd4

Not the best move, but good and scary - if your opponent can be scared. I doubt that La Dame Blanche shook to its bits, but it might be a good move to try against a human!

11.Qxg7+

White blunders immediately, but surely this must be a coincidence?

Two other choices: 11.Nc3 Kf7 12.d3 Nf6 13.Rf1 Be6 14.Bd2 Rhf8 15.O-O-O Kg8 16.Nb5 Bb6?? 17.Nxd4 Bxd4 18.c3, Black resigned, MrJoker - rgiblon, Internet Chess Club, 2013; and

11.d3 (best) Kf7 12.c3 Qd8 13.d4 exd4 14.b4 Be7 15.O-O+ Ke8 16.Qxg7 Bf6 17.Qg3 Qe7 18.Bf4 a5 19.e5 Bh4 20.Qf3 axb4 21.cxd4 Qf7 22.g3 Be7 23.Rf2 h5 24.Qe4 h4 25.Nd2 Qf5 26.Qf3 Nh6 27.Nf1 Ng4 28.Ne3 Nxe3 29.Qxe3 Be6 30.Qf3 hxg3 31.hxg3 c6 32.g4 Qg6 33.Bh2 Rh4 34.Rg2 Bd5 35.Qf5 Qxf5 36.gxf5 Bxg2 37.Kxg2 Rxd4 38.Bg1 Rd2+ 39.Kf1 b3 40.f6 b2 41.Rb1 Rad8 42.Be3 Rd1+ 43.Kf2 Rxb1 44.fxe7 Rd5 White resigned, Junior 7 -Fritz 8, The Jeroen Experience, 2003.

11...Kd6

Somewhat better was 11...Ke8, 12. Nc3 Qf2+ 13. Kd1 Nf6 14. Re1 Rg8 15. Qxg8+ Nxg8 16. Ne2 Qxg2 17. d4 Bxd4 White resigned, Fritz 5.32 - Fritz 8, The Jeroen Experience 2003. 

12.Kd1

The text is better than White's other choice in the tournament: 12.d3 Qf2+ 13.Kd1 Nf6 14.Bg5 Bg4+ 15.Kc1 Be3+ 16.Bxe3 Qxe3+ 17.Nd2 Raf8 18.d4 Rhg8 19.dxe5+ Kc6 20.Qe7 Nxe4 21.Qb4 Nxd2 22.Qxd2 Qxd2+ 23.Kxd2 Be6 24.g3 Rf2+ 25.Ke3 Rf5 26.Rhe1 Rxe5+ 27.Kf2 Rf5+ 28.Kg1 Bd5 29.c4 Bf3 30.Re6+ Kd7 31.Rae1 h5 32.Re7+ Kc8 33.R1e5 Rff8 34.Rc5 c6 35.Ra5 Kb8 36.Ra3 Rg5 37.Rae3 Bg4 38.b4 Bc8 39.c5 Rd5 40.R7e5 Bh3 41.Re8+ Rxe8 42.Rxe8+ Kc7 43.Kf2 Rd2+ 44.Re2 Rxe2+ 45.Kxe2 Bg4+ 46.Ke3 b6 47.Kd4 a5 48.a3 a4 49.Kc3 b5 50.Kd3 Kd7 51.Ke3 Ke7 52.Kd3 Kf6 53.Ke4 Bf5+ 54.Kf4 Bh3 55.Ke4 Ke6 56.Kd4 Bf5 57.h3 Bxh3 58.Ke4 White resigned, Zarkov 4.70 - La Dame Blanche 2.0c, Torneo tematico GaJero00-A, 2009. 

12...Qxe4 13.h3 Qg6

14.Qxh8

This leads to checkmate in 11 moves. (These are computer chess players we are talking about.) 

14...Qh5+ 15.Ke1 Qh4+ 16.Ke2 Bxh3 17.Rxh3 Qf2+ 18.Kd3 Qf1+ 19.Ke4 Qxg2+ 20.Rf3 White resigned

There follows 20...Qg4+ 21.Rf4 Qxf4+ 22.Kd3 Qf3+ 23.Kc4 Qe4+ 24.Kc3 Qd4+ 25.Kb3 Kb4 checkmate

From the Scacchi64.com Jerome Gambit Thematic

Torneo tematico GaJero00-A  2009

                      1 2 3 4 5 6 7 8
1 Rybka 2.3.2a (2 CPU) ** 11 01 01 1½ 11 11 11 11.5/14
2 WB Nimzo 2000b       00 ** 01 11 1½ 11 ½1 11 10.0/14
3 SOS 5.1              10 10 ** 00 11 11 11 ½1 9.5/14
4 Comet B48            10 00 11 ** 10 01 11 11 9.0/14
5 Zarkov 4.70          0½ 0½ 00 01 ** 1½ 01 11 6.5/14
6 DrunkenMaster 1.2 00 00 00 10 0½ ** 10 11 4.5/14
7 La Dame Blanche 2.0c 00 ½0 00 00 10 01 ** 01 3.5/14
8 Demon 1.0            00 00 ½0 00 00 00 10 ** 1.5/14



The crosstable above is for the Jerome Gambit thematic chess tournament presented at the Scacchi64.com website, referred to in an earlier post (see "The Macbeth Attack").

As can be seen, 56 games games were played (with an average of 51 moves) with White scoring 31%.

This compares to the 12,478 games in The Database with the 1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ move order,  with White scoring 45%, in games averaging 31 moves.

The difference in performance for White between the tournament and the larger collection can be in part attributed to sampling bias (players tend to more often publish their wins with their favorite openings, rather than their losses, and these could be over-represented in The Database) but the fact that about 80% of the relevant Jerome Gambit games in The Database are drawn from 17 years of games from the Free Internet Chess Server (FICS) - regardless of outcome - mitigates against that. It is likely that computers defend better than average club players when it comes to facing "refuted" opening play.

The difference in average game length between the two collections can be attributed to computer engines tendency to play to mate. It is interesting to point out several long games from the thematic tournament

WB Nimzo 2000b - La Dame Blanche 2.0c

drawn after 109 moves, via the 50-move rule; little progress can be expected in this Bishops-of-opposite-colors endgame anyhow

Zarkov 4.70 - DrunkenMaster 1.2

drawn after 93 moves, again via the 50 move rule

Some of the endgames were quite hard-fought, however. Consider the following position, from Rybka 2.3.2a - Zarkov 4.70, after 62.Kg7

There is a lot going on, even for a computer chess engine to grasp. Black wins by giving up his Knight and bringing his Rook back to exchange itself for White's advanced passed pawn (!) with 62...Rd2! 63.Kxf7 Rd7+ 64.Kg6 Rxh7 65.Kxh7 b4 and Black's passers will produce a winning Queen.

Instead, the game continued

62...Rh2!? 

A very direct move and sacrifice that, unfortunately, serves only to draw.

63.Rxh2 a1=Q 64.Kxf7 Qa7+ 

Black must check the enemy King and hold the enemy pawns back, hoping for repetition.

65.Kg6 Qb6+ 66.Kh5 Qd4 67.Rh3+ 

White, too, must worry about the enemy passed pawn - as well as the fact that Black has Q vs R.

67...Kc2 68.g5 b4 69.Rh2+ Kc3 70.Rh3+ Kb2 71.Rd3 

Nice. If Black now takes the Rook, White Queens his h-pawn. Either way, however, the game remains drawn.

71...Qh8 72.g6 Qf6 73.Rg3 Qg7 74.Re3 Qf8 75.Re7 

The same idea as above: taking the Rook leads to pawn promotion (and a draw).

75...Qf5+ 76.Kh6 Qf8+ 77.Kh5 Qh8 78.Kh6 Qd8 79.g7 

It looks like Rybka will finally break through, but Zarkov has the half-point in hand.

79...Qd6+ 80.Kh5 Qh2+ 81.Kg6 Qc2+ 82.Kh6 Qh2+ 83.Kg6 Qc2+ 84.Kh6 Qh2+ 85.Kg6 drawn