Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...f5/4. exf5

Jaenisch gambit accepted
	a b c d e f g h 8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1 a b c d e f g h
	Position in Forsyth-Edwards Notation (FEN) r1bqkbnr/pppp2pp/2n5/1B2pP2/8/5N2/PPPP1PPP/RNBQK2R
	Moves: 1. e4 e5 2. Nf3 Nc6 3. Bb5 f5 4. exf5
	ECO code: C63
	Parent: Spanish game → Jaenisch gambit

4. exf5!? · Jaenisch gambit accepted

Accepting the "free" pawn is inaccurate, as Black can regain the pawn with extra tempi and space.

After 4...e4, White's knight is kicked and is low on squares: g5 and h4 are controlled by Black'[s queen, while Black's knight controls e4 and d5. (The addition of this knight is the key difference between the Jaenisch and Latvian gambits accepted, 1. e4 e5 2. Nf3 f5?! 2. exf5!) Un-developing the knight to g1 would be a big concession to Black.

To make room for the knight to go elsewhere, White has the manoeuvre 5. Qe2, pinning and attacking the e4 pawn, 5...Qe7 un-pins it, 6. Bxc6 with the idea of moving the knight to d4 where it defends the f5-pawn from Black's bishop. 6...dxc6 7. Nd4 =. White may followed with Ne6 in some lines, such as after 7...Qe5. After 6...bxc6 7.Nd4, Black will likely play 7...Nf6, and eventually either Qe5 or c5 and then d5 to try to win the pawn back.

5. Bxc6 dxc6 6. Nd5? ⩱ allows 6...Bxf5 with the threat of ...Qd4. If 6. Qe2 the line can transpose if Black plays 6...Qe7, but better is 6...Bxf5 ⩱.

History

Though not now considered an accurate way to refute the gambit, giving Black an even game, 4. exf5!? has been seen occasionally. Capablanca lost in this line to William Pratt in an exhibition simul game in 1909.^[1]

Sample game

Paul de Schloezer vs Mikhail Chigorin, 1878^[2]

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After 11. Kd7, Black threatens ...Bg4#.

1. e4 e5 2. Nf3 f5 3. exf5 Nc6?! 4. Bb5?

This position is arrived at by transposition from a Latvian gambit. 4. d5 was better: allowing both bishops into the game, White would be able to answer 4...e4 with 5. Ng5! and the knight is defended.

4...Bc5?!

4...e5 is an improvement and the main move today. The text move allows 5. O-O, and due to the open e-file White at the minimum wins the pawn (e.g. 5. O-O, threatens Nxe5 as ...Nxe5 Re1! is a pin, 5...d6? 6. Re1 Nf6 7. d4 Bb6 8. dxe5 Ng4 9. exd6+ Kf8 ∓).

5. Bxc6 dxc6 6. Nxe5 Bxf5

6...Bxf2+ 7. Kxf2 Qd4+ attacking the knight wins Black a pawn back

7. Qh5+ g6 8. Nxg6??

This appears to be winning material but in fact White's king is too weak.

8...hxg6 9. Qxh8 Qe7+ 10. Kd1 Bxf2

10...Bg4+ would be mate were it not for 11. f3, so Black first eliminates the f-pawn.

11. Qxg8+? Kd7 12. Qc4

Black is down six points of material but has an overwhelming attack on White's king, who is stranded in the middle of the board, and White has only their queen developed. White attempts to stop the bishop from coming to g4.

12...Re8 0-1

Black threatens ...Qe1+ Rxe1 Rxe1#.

Theory table

1. e4 e5 2. Nf3 Nc6 3. Bb5 f5 4. exf5

	4	5	6	7	8	9	10
Jaenisch gambit accepted	... e4	Qe2 Qe7	Bxc6 dxc6	Nd4				=
	... ...	Bxc6?! dxc6	Qe2 Bxf5	d3 Qe7	dxe4 Qxe4	Qxe4+ Bxe4	O-O Bxf3	⩱

Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...f5/4. exf5

4. exf5!? · Jaenisch gambit accepted

History

Sample game

Theory table

References

See also