Tuesday, November 1, 2022

Jerome Gambit quick checkmate


The new short YouTube video "Jerome Gambit quick checkmate" is entertaining and raises a number of questions that are great fun to try to answer.


Stockfish - Cramlingbot

Chess.com, 2021

So, we have a game between two computer chess engines, the second representing Anna Cramling, Twitch chess streamer.

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ 

4...Kxf7 5.Nxe5+ Nxe5 6.Qh5+ Ke6 

7.f4 Qf6 8.Rf1 Kd6 


This is an unexpected move.

More usual would have been 8...d6, offering to return a piece with the same idea as in the "silicon" or "annoying" defense (1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ Kxf7 5.Nxe5+ Nxe5 6.Qh5+ Ke6 7.f4 d6). Stockfish 15 then shows that 9.fxe5 Qg6!? is the only way for Black to continue to maintain his advantage.

The Database has 6 games with 8...d6. Black won 5 of them.

What to make of Black's 8th move? It looks like a "mouse slip", a very human type error. Computers don't "mouse slip" do they? 

Actually, there is a funny Tweet that suggests that the Cramlingbot is capable of such an error
The bot on is pretty accurate, they even programmed it to mouse slip in the endgame.

9.Nc3 

The right choice of moves.

Grabbing a piece with 9.fxe5+ Qxe5 10.Qxe5+ Kxe5 or 9.Qxe5+ Qxe5 10.fxe5+ Kxe5 would take the Queens off of the board, leaving White with only one pawn for his sacrificed piece, and Black with a well developed and relatively safe King.

White was successful after 9.d4 Bxd4? 10.fxe5+ Bxe5 11.Rxf6+ Bxf6 12.Bf4+ Ke7 13.e5 d6 14.exf6+ Nxf6 15.Qe2+ Kf7 16.Nc3 Bf5 17.Kd2 Rae8 18.Qc4+ Be6 19.Qxc7+ Re7 20.Qxd6 Rd7 21.Re1 Rxd6+ 22.Bxd6 Rd8 23.Kc1 Rxd6 24.h3 Nd5 25.Ne4 Rd7 26.Ng5+ Kf6 27.Nxe6 Re7 28.g4 Rxe6 29.g5+ Kf7 30.Rf1+ Ke7 31.h4 Nf4 32.Rxf4 Re2 33.Rb4 b6 34.Ra4 Kd6 35.Rxa7 White was better and won on time, jpayero - nathanael31, 1 0 bullet, lichess.org, 2022.

However, 9...Nd3+ 10.cxd3 Qxd4 instead would have given Black an edge. 

9...Qe6 


Another curious move. (There are ways to make a smart computer dumber. See "Jerome Gambit: Artificial Wha?")

Certainly Black could have played 9...Nc6, 9...Nb6 or 9...Nf7, instead, planning on meeting 10.e5+ with 10...Nxe5, returning a piece. That would be a reasonable plan, but The Database has no games with any of those 3 moves.

Another idea would be to move the King again, i.e. 9...Kc6 10.fxe5 (10.b4!?) 10...Qg6 11.Qe2 a6? (11...b6) 12.Qc4 (12.b4!?) 12...Qe6 13.Nd5 Ne7?! (13...b514.d4 b6 15.Nxe7+ Qxe7 16.Qd5+ Kb5 17.c4+ (17.a4+ Ka5 18.Bd2#) 17...Ka4 18.b3+ Ka5 19.Bd2 checkmate, jpayero - nathanael31, 3 0 blitz, lichess.org, 2022.

A reasonable choice was 9...c6, which appeared in 2 games: 10.fxe5+ (10.Ne2 g6?! 11.fxe5+ Qxe5 12.Qxe5+ Kxe5 13.b4 Bxb4 14.Bb2+ Black resigned, VM5715080 - draveilpb, 10 0 blitz, lichess.org, 2021) 10...Qxe5 11.Rf5 Qd4 (11...g6?! 12.Rxe5 gxh5 13.Re8 Kc7 14.d3 b6 15.Bf4+ d6) 12.Qg4 Qg1+ (12...Nf6) 13.Rf1 Qd4 14.d3 Nf6?! (14...Kc7) 15.Bf4+ Ke7 16.Qxg7+ Kd8 17.Qxh8+ Ke7 18.Bg5 Kd6 19.Bxf6 Qe3+ 20.Ne2 (20.Kd1 Qd4 21.Qe8 Qxf6 22.Rxf6+ Kc7 23.Qe5+ d6 24.Rf7+ Kb6 25.Qe7 a5 26.e5 Ka6 27.exd6 Bg4+ 28.Kd2 Rb8 29.Qc7 Ba7 30.d7 Rd8 31.Qxd8 Bc5 32.Qa8+ Ba7 33.d8=Q Bc8 34.Qaxc8 Be3+ 35.Kxe3 h5 36.Qxb7#) 20...Bb4+ 21.c3 Kc5 22.d4+ Kc4 23.cxb4 Kd3 24.Rc1? (24.Rf3 Qxf3 25.gxf3 Kc4 26.Qf8 b6 27.a4 c5 28.Qh6 cxd4 29.Qd2 Kb3 30.Ra3+ Kc4 31.Qxd4#) 24...Qxe2 checkmate, carlson85 - E-Shaposhnikov, 1 0 bullet, lichess.org, 2020

10.d4 Bb4

This move does not help things, but 10...Bxd4 would lead to complications and the loss of a piece after 11.Nb5+ i.e. 11...Ke7 12.Nxd4. It turns out that Black can not protect the Bishop with 11...Kc5 because 12.Nxd4 Kxd4 13.Be3+ would lead to checkmate. (12...Qd6 would be better than the recapture, but would drop the piece.)

White's attack now builds and ends in mate.

11.fxe5+ Ke7 12. Bg5+ Nf6 13.exf6+ Kf8 

14.fxg7+ Kxg7 15.Bh6+ Kg8 16.Qg5+ Qg6 17.Qd8+ Qe8 18.Qxe8+ Bf8 19.Qxf8 checkmate




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