Friday, February 10, 2017

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.


Wednesday, February 8, 2017

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!

Monday, February 6, 2017

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.