Jerome Gambit Discovery

I enjoyed looking at positions in the Jerome Gambit with the help of Stockfish 8 - to the depth of 30 ply - that I thought I would look at a few of the classical defenses and see what turns up.

My first surprise came in Blackburne's Defense.
 
dj222 - invincible1
GameKnot.com, 2003

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+

4...Kxf7 5.Nxe5+ Nxe5 6.Qh5+ g6 7.Qxe5 d6

Blackburne's Defense. It is a complicated, tactical mess. Initially thought to favor Black, and then to favor White, the current assessment has been that it leads to a complicated draw that either player avoids at his own peril. But, maybe it favors White after all.

8.Qxh8 Qh4 9.d4

See "Traps and Zaps" for some background. The move was suggested in the notes to Amateur - Blackburne, London, 1885, but given scant attention afterward. 

Far more often played is 9.0-0. Although White won in Chandler - Dimitrov, 2004, analysis supported a complicated drawn game.

9...Nf6

Black ignores the danger his Bishop is in. Only one game in The Database has this move, which is Stockfish 8's top choce.

It is hard for Black not to plump for 9...Qxe4+ 10.Be3 Qxg2 with complications, but the text is the second player's best option.

Check out "Opening Traps by GM Ferzbery" for a look.

10.Nd2

White does not go after the enemy Bishop, but keeps White's Queen away from e4.

10...Bxd4 11.Rf1

It was probably best to play 11.0-0 here, and ride out the storm after 11...Qxh2+ 12.Kxh2 Ng4+ 13.Kg3 Bxh8, coming out the exchange ahead.

11...Bh3

Recovering a pawn and offering a Rook while threatening White's Queen! Unfortunately, it is a mistake: Black had better in 11...b6 with the idea of 12...Ba6 and a very complicated, but balanced, game.

12.Qxa8 Bxg2 13.Qxb7 Bxf1 14.Qb3+ Ke7 15.Qg3

White's Queen returns in time to save the King.

15...Qxg3 16.hxg3 Bg2 17.f3 Bh3 Black resigned

Stumbling to the Top

My last comment about the Chess.com Giuoco Piano thematic tournament that I most recently played in (see "Unlinked") was a bit melancholy

And - I'm sitting on top of the standings in the Chess.com Giuoco Piano tournament, one point ahead of the field (thanks, in part, to the Jerome Gambit). However, IlToscano has two games left, so he can catch and pass me... 

Surprisingly, once again (see "An Unexpected Success") the competition was fierce enough amongst other players that it turns out that nobody will be able to catch me after all (there are a couple of games not yet finished).

Another inexplicable first place finish, assisted by a 7-2 record with the Jerome Gambit.  

Jerome Gambit: Synthesis

What can we make of the last two posts (see "Jerome Gambit: What Are the Odds?" and "Jerome Gambit: Stockfish 8 Checks In"), each of which provides useful information about the Jerome Gambit?

First, we need to recall Geoff Chandler's very useful and very practical chart.

Here is a one-move blunder table showing how severe the blunder needs to be in a game between two players of the same grade.

All players should be able to spot their opponent leaving a mate in one on.
A 1200 player should win if an opponent blunders a Queen or a Rook. But not necessarily if they pick up a Bishop or Knight.
1500 players often convert piece-up games into a win, but this is not the case if a pawn or two up.
An 1800 player usually wins if they are two pawns up.
In a game between two 2000+ players a blundered pawn is usually enough to win.

This chart immediately addresses a couple of questions:

Q: Why do masters not play the Jerome Gambit?
A: According to Chandler, a pawn advantage is enough for a master to win the game. In the Jerome, White sacrifices one or two pieces, and Stockfish 8 evaluates the position with 4.Bxf7+ as giving Black a 1.85 pawn advantage. That would be self-injurious in a master vs master game.

Q: So why is it that, according to The Database, White scores 45% after 4.Bxf7+ ?
A: Recall that The Database contains primarily club-level games played on the internet. We can see from Chandler's chart that players rated 1200 and 1500 often need more than "almost two pawns" to win. Even an 1800 rated player only "usually" wins when two pawns up - and the Jerome Gambit sacrifices 1.85. The errors of the Jerome Gambit fit right in with the errors of club play.

What else?

Both practice and computer analysis (as well as common sense) strongly suggest that Black should accept the Bishop after 4.Bxf7+. To refuse it is to give White a better (but not necessarily winning) game.

Black should also accept the Knight after 5.Nxe5+ (Stockfish 8's top choice for White here, at 30 ply search; although it rates almost as good 5.0-0, 5.c3, 5.d3, 5.Qe2 and 5.Nc3.) Best play is for the defender to be brave, but that does not always come easy for club players.

Practical play and computer analysis suggest that White garners further risk in playing the Italian Four Knights Jerome Gambit, as opposed to the main line classical variation.

The Database and Stockfish 8 slightly prefer 6.Qh5+ over 6.d4, but only slightly. It is worth being comfortable with both.

Both the Semi-Italian Jerome Gambit (1.e4 e5 2.Nf3 Nc6 3.Bc4 h6 4.0-0 Bc5 5.Bxf7+) and the Blackburne Shilling Jerome Gambit (1.e4 e5 2.Nf3 Nc6 3.Bc4 Nd4 4.Bxf7+) improve White's chances over the main line Jerome Gambit, according to both The Database and Stockfish 8.

Based on practice, Black defends best against 6.Qh5+ with 6...Kf8. Stockfish 8, instead, prefers 6...Ke6. The move 6...g6 - from Blackburne's wonderful crush of the Jerome - scores poorly according to The Database, while Stockfish 8 says it leads Black to an advantage of 1.55 pawns.

The computer's choice of 6...Ke6, which it rates as -2.42, fits in well with computers in general preferring the "annoying defense" (continuing 7.f4 d6) and pushes the defender's advantage to almost 2 1/2 pawns. It may be the complexity of the line, or it may be that it is played by weaker club players, that accounts for being less successful (per The Database) than 6...Kf8 in play. 

Finally: the Jerome Gambit is a light-hearted opening for practicing attack (or defense) and performs best in casual or blitz play, or when White is giving a lesser-rated player "Jerome Gambit" odds. You are not likely to see Magnus Carlsen playing any time soon.

Jerome Gambit: Stockfish 8 Checks In

In the previous post I spent a little time with The Database and came up with some scoring percentages for White for different lines of play in the Jerome Gambit.

I gave two caveats:

All statistics need to be approached cautiously. In this case it is useful to remember that the vast majority of games in The Database are drawn from over a decade of games played online at FICS, regardless of outcome; so they should be somewhat representative of Jerome Gambit play among club players who contest online... 

Of course, were I to subject each of these positions to the scrutiny of, say, Stockfish 8, the computer's evaluation would likely, in some cases, vary significant from the game outcomes in The Database!

Then I decided to give Stockfish 8 a chance, after all.

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5

If the game continues 3...Nd4 4.Bxf7+ instead, Stockfish 8 rates the position at 30 ply depth of search as -.18, about an even game.

4.Bxf7+

Stockfish 8 rates the position as -1.85 at 30 ply depth of search, meaning that Black is not quite 2 pawns better.

If Black plays 4...h6 instead, after 5.0-0 Bc5 6.Bxf7+ Stockfish 8 rates the position as -1.77 at 30 ply search depth. After 5.Nc3 Bc5 6.Bxf7+, it rates the position at 30 ply search depth as -1.45.

4...Kxf7

As for declining the Bishop, Stockfish 8 rates 4...Kf8 at 30 ply depth of search as +1.68, giving White more than a pawn and a half advantage. It rates 4...Ke7 at +2.01, giving White a two pawn advantage.

5.Nxe5+

Stockfish 8 rates this position as -2.41 at 30 ply depth of search. 

If, instead, the game continues 5.Nc3 Nf6, the game reaches the Four Knights variation by transposition. Stockfish 8 rates the position as -2.85 at 30 ply depth of search.

5...Nxe5

Stockfish 8 rates this position as -2.32 at 30 ply depth of search.

If Black replies, instead, 5...Kf8, Stockfish 8 rates the position -.56; if Black replies 5...Ke8 Stockfish 8 rates the position +.22; if Black replies 5...Ke6, Stockfish 8 rates the position +.94; if Black replies 5...Ke7, Stockfish 8 rates the position +1.04; all at 30 ply depth of search.

6.Qh5+

Stockfish 8 rates this position as -2.27 at 30 ply of depth.

If White plays 6.d4 instead, Stockfish 8 rates the position as -2.46 at 30 ply depth.

6...g6

Stockfish 8 rates this position as -1.55 at 30 ply of depth.

It rates 6...Kf8 as -1.75 ; 6...Ke6 as -2.42; and 6...Ke7 as +2.71; all at 30 ply of depth.

Jerome Gambit: What Are the Odds?

I spent a little time with The Database today, and came up with the following numbers.

All statistics need to be approached cautiously. In this case it is useful to remember that the vast majority of games in The Database are drawn from over a decade of games played online at FICS, regardless of outcome; so they should be somewhat representative of Jerome Gambit play among club players who contest online.



1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5

The Database has 5,307 games where the game continues 3...Nd4 4.Bxf7+ instead. White scores 56%.

4.Bxf7+

The Database has 12,662 games reaching this position. White scores 45%.

The Database has 4,589 games where Black plays 4...h6 instead. White scores 55%. This includes 187 games which continue 5.0-0 Bc5 6.Bxf7+, where White scores 65%; and 141 games which continue 5.Nc3 Bc5 6.Bxf7+, where White scores 54%.

4...Kxf7

The Database has 12,763 games reaching this position. I am not sure why this number is larger than the earlier one! White scores 45%

The Database has 272 games where Black declines the Bishop with 4...Kf8. White scores 55%. The Database has 41 games where Black declines the game with 4...Ke7. White scores 72%.

5.Nxe5+

The Database has 5,613 games reaching this position. White scores 54%.

The Database has 2,510 games where the game continues 5.Nc3 Nf6, or the game reaches the Four Knights variation by transposition. White scores 38%

5...Nxe5

The Database has 5,348 games reaching this position. White scores 54%.

The Database has 202 games where Black replies, instead, 5...Kf8. White scores 52%. The Database has 103 games where Black replies 5...Ke8; White scores 59%. The Database has 24 games where Black plays 5...Ke6; White scores 65%. The Database has 12 games where Black replies 5...Ke7; White scores 67%.

6.Qh5+

The Database has 3,804 games with this position. White scores 55%.

The Database has 1,528 games where White plays 6.d4 instead. White scores 52%.

6...g6

The Database has 471 games with this position. White scores 71%.

The Database has 570 games where Black plays 6...Kf8 instead. White scores 50%.

The Database has 960 games where Black plays 6...Ke6. White scores 54%.

The Database has 1 game where Black plays 6...Ke7. White scores 100%


Of course, were I to subject each of these positions to the scrutiny of, say, Stockfish 8, the computer's evaluation would likely, in some cases, vary significant from the game outcomes in The Database!

Jerome Gambit: Black Must Castle-by-Hand

I received a new Jerome Gambit game from Vlasta Fejfar. His opponent quickly solves the problem of the light square Bishop, but, instead, his Knights trip all over each other. White's attack against the uncastled King wins.

Vlastous - koden
internet, 2017

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ 

4...Kxf7 5.Nxe5+ Nxe5 6.Qh5+ Ng6 7.Qd5+Ke8 8.Qxc5 d6 9.Qe3 Be6 

The Bishop never finds a comfortable place to stay. At e6 it encourages White to play f2-f4-f5.

10.O-O Qd7 11.f4 Bf7 12.d4 Bc4

Black moves the piece again, and may feel comfortable in that, in attacking White's Rook, he gains a tempo. The truth is that White is "forced" to make a move that he is happy to make, anyhow. In the meantime, Black's King remains a target in the center of the board.

13.Re1 N8e7 14.f5 Nf8 15.d5 

More danger for the Bishop.

White now sacrifices a pawn to open the center and fuel his attack.

15...c6 16.Na3 cxd5 17.exd5 Bxd5 18.Qd3 Bc6 19.Bg5 

Black resigned

Black will lose his Queen for a Rook and Knight. His King will still be stuck in the center, and White's attack will proceed along the helpfully opened center files.

Jerome Gambit: "Cliff Hardy" Spectacular

Another "Cliff Hardy" spectacular! A very interesting Jerome Gambit played with a time control of one minute for each player. (That turns out to be 1 or 2 seconds a move.)

Again, I present notes from Kevin, with some information from his email. I have added diagrams. 

I couldn't resist sending you this game in the "Charlick" variation, played in the famous Jerome Gambit game, Charlick-Mann, correspondence, 1881. I am from Adelaide in Australia. Our official chronological State Championship winner board ( http://www.oocities.org/timessquare/5427/ ) starts with "1868-93 H. Charlick 1894 J. Hilton; 1895 W. J. McArthur..." and ends with "2016 Alan Goldsmith" but there is an interesting wordy preface to the "1868-93 H. Charlick" bit:

"Historical Prelude - Henry Charlick (1845-1916) was acknowledged chess champion of S.A. [South Australia] for 25 years, by common consent and by his pre-eminent ability. He confirmed this rank by winning the Australian title in Adelaide in 1887 and by taking second place the next year in Melbourne. State Championship tournaments began in 1894, after the foundation of the S.A.C.A [South Australian Chess Association] in 1892, but Charlick never took part in these contests for the title he had relinquished."

Kevin Sheldrick - NN

1 0, FICS, 2017 

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ 

4...Kxf7 5.Nxe5+ Nxe5 6.Qh5+ Ng6 7.Qd5+ Kf8

Charlick-Mann, correspondence, 1881, went 7...Ke8, ...1-0, 72.

8.Qxc5+ d6 9.Qe3 Nf6 10.0-0 Bd7?!

Black is now slightly better but Stockfish likes the manoeuvre 10...Kf7!, intending to artificially castle, with a clear advantage for black.

11.f4

Stockfish slightly prefers 11. d4.

11...h6?!

Doesn't do much - 11...Qe8 or 11...c5 are better.

12.d4 Qe7?!

Looks good but 12...Bb5 is better - a few mistakes around here but I guess this is "one minute each" chess 😃.

13.Nc3?!


13.e5! is a little better.


13...Kg8 14.f5 

Now I am equal.

14...Nf8 15.e5 de 16.de Ne8??

16...Rae8! or 16...Ng4 are better, though I am not losing a pawn after 16...Ng4 17.Qg3!, since 17...Nxe5?? loses to 18.f6.

17.Qe4??

17.Nd5! was crushing, with the threat of pushing the f-pawn.

17...Qc5??

17...Bc6 was necessary to keep black in the game, now the Jerome pawns are too strong.

18.Be3 Qc6 19.Qf4

OK, but 19.Nd5! was even stronger.

19...a6 20.e6 Bc8?!

Sacrificing with 20...Nxe6 was better but still losing for black.

21.Bd4 Nd6 22.Qg3?!

22.f6! was killing.

22...Ne8 23.f6 Nxe6 24.f7+ Kh7 25.Qd3+ g6 26.fxe8=Q Rxe8?

26...Qxe8 is better, though 27.Nd5 is still winning for white.

27.Rf7+ Kg8

27...Ng7 would still lead to a quick mate e.g. 28.Rxg7+ Kh8 29.Rxg6+ Kh7 30.Rg7+ Kh8 31.Qh7 mate

28.Qxg6 Ng7 29.Qxg7 mate