# Chess Opening Theory/1. e4/1...e5
## 1...e5 · Open Game

1...e5, the Open Game (or Double King's Pawn Game), is Black's classical response to 1. e4. By mirroring White's move, Black grabs an equal share of the centre and scope to develop some pieces. 1...e5 is one of the few moves that directly interferes with White's ideal plan of playing d4.
But, the move's merit is also a drawback: the longer the position remains symmetrical, the longer White will have an advantage by moving first. Also, the pawn on e5 is undefended, and it is easy for White to develop in a way that restricts Black's possible responses, by simply threatening to capture it.
Though the move is still common at every level, it saw a modest decline in popularity during the 20th century.

### White's responses

| | a | b | c | d | e | f | g | h | |
| 8 | | | | | | | | | 8 |
| 7 | | | | | | | | | 7 |
| 6 | | | | | | | | | 6 |
| 5 | | | | | | | | | 5 |
| 4 | | | | | | | | | 4 |
| 3 | | | | | | | | | 3 |
| 2 | | | | | | | | | 2 |
| 1 | | | | | | | | | 1 |
| | a | b | c | d | e | f | g | h | |
The overwhelmingly popular move here – about 10 times more common than everything else combined – is 2. Nf3.
This threatens Black's undefended pawn while developing a piece in preparation for castling on the kingside. The developed knight also defends the d4 square preparing for a future d2-d4 pawn push.
2. Bc4, the Bishop's Opening, and 2. Nc3, the Vienna Game, are simple alternative ways of developing a piece.
They don't give Black a particular problem to deal with, but they aren't bad moves either, and they keep open the option of either d4 or f4.
| | a | b | c | d | e | f | g | h | |
| 8 | | | | | | | | | 8 |
| 7 | | | | | | | | | 7 |
| 6 | | | | | | | | | 6 |
| 5 | | | | | | | | | 5 |
| 4 | | | | | | | | | 4 |
| 3 | | | | | | | | | 3 |
| 2 | | | | | | | | | 2 |
| 1 | | | | | | | | | 1 |
| | a | b | c | d | e | f | g | h | |
Another plan is to try and lever open the f-file for an attack on Black's weak f7 point with 2. f4, the King's Gambit.
This was popular in Victorian times and earlier, but Black has now found a few reliable ways of grabbing the proffered pawn and keeping it.
| | a | b | c | d | e | f | g | h | |
| 8 | | | | | | | | | 8 |
| 7 | | | | | | | | | 7 |
| 6 | | | | | | | | | 6 |
| 5 | | | | | | | | | 5 |
| 4 | | | | | | | | | 4 |
| 3 | | | | | | | | | 3 |
| 2 | | | | | | | | | 2 |
| 1 | | | | | | | | | 1 |
| | a | b | c | d | e | f | g | h | |
Or, White can smash the centre open with 2. d4 in order to develop pieces with great speed, sacrificing a pawn or two if necessary.

#### Less common responses

Other less common moves:
   * 2. d3 - Indian Opening
   * 2. Qh5 - Parham Attack
   * 2. Qf3 - Napoleon Opening
   * 2. c3 - Centre Pawn Opening
   * 2. Bb5 - Portuguese Opening
   * 2. Ne2 - Alapin's Opening
   * 2. g4 - Fernando Torres Variation
   * 2. Ke2? - Bongcloud Attack
   * 2. b3!? - Charles' Opening
   * 2. Qg4? - Speers Attack

## Statistics
### Approximate chances

    White win 51%, Draw ??%, Black win 45%.

### Estimated next move popularity

    Nf3 82%, Bc4 5%, Nc3 4%, f4 4%, d4 2%, all others less than 1%
| move | average | 365Chess.com (big) | Chess Tempo (all) | chessgames.com | Lichess (masters) | Lichess (database) |
| 2. Nf3 | 82.1% | 86.0 | 87.3 | 84.7 | 91.7 | 61.1 |
| 2. Bc4 | 4.8 | 3.8 | 3.7 | 2.9 | 3.2 | 10.4 |
| 2. Nc3 | 4.4 | 4.2 | 4.1 | 4.8 | 2.7 | 6.2 |
| 2. f4 | 4.1 | 3.7 | 3.0 | 6.1 | 1.7 | 6.1 |
| 2. d4 | 2.3 | 1.7 | 1.5 | 1.1 | 0.6 | 6.4 |
| 2. d3 | 0.6 | 0.1 | 0.1 | 0.0 | 0.0 | 2.9 |
| 2. Qh5 | 0.6 | 0.1 | 0.0 | 0.0 | 0.0 | 2.9 |
| 2. Qf3 | 0.3 | 0.0 | 0.0 | 0.0 | 0.0 | 1.3 |
| 2. c3 | 0.2 | 0.0 | 0.0 | 0.0 | 0.0 | 0.6 |
| 2. c4 | 0.1 | 0.1 | 0.1 | 0.0 | 0.0 | 0.4 |
| 2. f3 | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | 0.4 |
| 2. g3 | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | 0.3 |
| 2. Bb5 | 0.1 | 0.1 | 0.0 | 0.0 | 0.0 | 0.2 |
| 2. Ne2 | 0.1 | 0.0 | 0.0 | 0.1 | 0.0 | 0.1 |
| 2. g4 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| 2. Ke2 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| everything else | 0.2 | 0.1 | 0.1 | 0.0 | 0.0 | 0.8 |

## Theory table

1. e4 e5
| | 2 | 3 | 4 | 5 | 6 | 7 | Evaluation |
| Ruy Lopez | Nf3 Nc6 | Bb5 a6 | Ba4 Nf6 | O-O Be7 | Re1 b5 | Bb3 d6 | = |
| Bishop's Opening | Bc4 Nf6 | d4 exd4 | Nf3 Bb4+ | c3 dxc3 | bxc3 Bc5 | e5 d5 | = |
| Vienna Game | Nc3 Nf6 | f4 d5 | fxe5 Nxe4 | Nf3 Be7 | d4 Bb4 | Bd2 Bg4 | = |
| King's Gambit | f4 exf4 | Nf3 g5 | h4 g4 | Ne5 Nf6 | Bc4 d5 | exd5 Bd6 | = |
| Center Game | d4 exd4 | Qxd4 Nc6 | Qe3 Nf6 | Bd2 Be7 | Nc3 O-O | O-O-O d6 | = |
| Indian Opening | d3 Nc6 | f4 exf4 | Bxf4 d5 | exd5 Qxd5 | Nc3 Qa5 | Qd2 Bf5 | = |
| Parham Attack | Qh5 Nc6 | Bc4 g6 | Qf3 Nf6 | Ne2 Bg7 | Nbc3 d6 | O-O O-O | = |
| Napoleon Opening | Qf3 Nf6 | Bc4 Nc6 | Ne2 d6 | Nbc3 Bg4 | Qe3 Nb4 | Bb3 Be6 | = |
| Centre Pawn Opening | c3 d5 | exd5 Qxd5 | d4 Nc6 | Nf3 Nf6 | Nxe5 Nxe5 | Qe2 Be6 | = |
| Portuguese Opening | Bb5 c6 | Ba4 Nf6 | Nc3 Bc5 | Nf3 d6 | d3 a5 | Bb3 Nbd7 | = |
| Alapin's Opening | Ne2 Nf6 | d4 Nxe4 | f3 Ng5 | dxe5 Nc6 | f4 Ne6 | Nbc3 d6 | = |
| Tortoise Opening | Bd3?! | = |
| Fernando Torres Opening | g4? d5! | exd5 Qxd5 | Qf3 Qe6 | h3 Nc6 | Bb5 Bd7 | Ne2 O-O-O | =/+ |
| Bongcloud Attack | Ke2?! Nf6 | Nc3 Bc5 | Nf3 d5 | d3 Ng4 | Bg5 f6 | Bh4 d4 | -/+ |
For explanation of theory tables, see theory table and for notation, see algebraic notation.

## References

Bibliography
* Kasparov, Garry, & Keene, Raymond 1989 Batsford chess openings 2. ISBN 0-8050-3409-9.
* Modern Chess Openings: MCO-14. 1999. Nick de Firmian, Walter Korn. ISBN 0-8129-3084-3.
* Nunn's Chess Openings. 1999. John Nunn (Editor), Graham Burgess, John Emms, Joe Gallagher. ISBN 1-8574-4221-0.
* Panov, Vasily (1973). Teoría de Aperturas, Tomo I: Aperturas Abiertas - Aperturas Semiabiertas. ISBN 84-270-0132-0.
* Schiller, Eric (2002). Standard Chess Openings. ISBN 1-58042-048-6.

## External links

* 365Chess: 1. e4 e5
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