# Chess Opening Theory/1. c4
## 1. c4 · English Opening

The English Opening, which starts with 1.c4, is the fourth most commonly played opening move in chess. By playing this move, White allows the queen to move freely and also discourages Black from responding with 1...d5. Additionally, White ensures that the c-pawn will not be blocked behind a knight on c3. The resulting positions often resemble those that arise from 1.d4 openings rather than 1.e4 openings, and the move d4 is frequently played later on.
While this opening is not as sharp as 1.e4 or 1.d4, it is still effective in controlling the d5 square and is highly flexible, allowing for easy transpositions into other openings.

### Black's responses

* 1...Nf6 or 1...g6 are likely to transpose into an Indian Defence.
* 1...e5 is a "reversed" Sicilian Defence.
* 1...e6 will probably end up in a Queen's Gambit Declined. This is known as the Agincourt Defense. However, if White plays 2.d4 then Black plays 2...Nf6, it is a typical Indian game (1.d4 Nf6 2.c4 e6 is the normal order.)
* 1...c5 – most pure English lines come from the Symmetrical Variation and are quite hard to play and to understand.
* 1...c6 will usually either transpose into the Caro-Kann Defence or the Slav Defence.
* 1...f5, the Anglo-Dutch Defence, leads to sharp tactical lines for Black, but can open a powerful kingside attack. This is likely to transpose into the regular Dutch Defense after 2.d4.
* 1...b6 will in all likelihood transpose into the English Defence.
* 1...d5 is seldom played but may transpose into the Queen's Gambit or the Réti Opening.
* 1...b5 normally gives good chances for Black, even though the Halibut Gambit is considered unsound at the professional level.
* 1...g5, the Myers Defence, gives White a small advantage.

## Statistics
### Approximately chances

    White win 37%, Draw 34%, Black win 29%.

### Estimated next move popularity

    Nf6 28%, e5 23%, e6 13%, c5 12%, g6 8%, c6 7%, f5 3%. Other moves less than 2%.
| move | average | 365Chess.com (big) | Chess Tempo (all) | chessgames.com | Lichess (masters) | Lichess (database) |
| ...Nf6 | 28.2% | 30.9 | 30.3 | 31.4 | 28.4 | 20.0 |
| ...e5 | 23.2 | 22.6 | 23.0 | 22.0 | 24.0 | 24.6 |
| ...e6 | 13.4 | 13.2 | 13.4 | 14.4 | 14.4 | 11.7 |
| ...c5 | 11.7 | 11.8 | 11.9 | 11.4 | 11.5 | 12.0 |
| ...g6 | 7.7 | 8.0 | 7.6 | 8.4 | 8.2 | 6.6 |
| ...c6 | 7.4 | 6.9 | 7.4 | 7.1 | 8.3 | 7.0 |
| ...f5 | 2.8 | 3.5 | 3.1 | 2.9 | 2.5 | 2.0 |
| ...b6 | 1.7 | 1.5 | 1.6 | 1.4 | 1.6 | 2.3 |
| ...d5 | 1.6 | 0.2 | 0.2 | 0.1 | 0.0 | 7.7 |
| ...d6 | 1.4 | 1.0 | 0.9 | 0.6 | 0.7 | 3.8 |
| ...Nc6 | 0.5 | 0.4 | 0.4 | 0.3 | 0.3 | 1.1 |
| ...b5 | 0.1 | 0.0 | 0.0 | 0.1 | 0.0 | 0.5 |
| ...a6 | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | 0.2 |
| ...g5 | 0.0 | 0.0 | 0.1 | 0.0 | 0.0 | 0.1 |
| everything else | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | 0.5 |

## Theory table

| 1.c4 |
| | 1 | 2 | 3 | 4 | 5 | 6 |
| Symmetrical Variation | c4 c5 | Nf3 Nf6 | g3 b6 | Bg2 Bb7 | O-O g6 | | = |
| Reversed Sicilian Defence | ... e5 | Nc3 Nc6 | Nf3 Nf6 | g3 d5 | cxd5 Nxd5 | | ∞ |
| Agincourt Defence | ... e6 | Nc3 Bb4 | Qb3 Nc6 | Nf3 Nf6 | a3 Bxc3 | | ∞ |
| Anglo-Slav Variation | ... c6 | Nf3 d5 | g3 Nf6 | Bg2 dxc4 | O-O Nbd7 | | ∞ |
| Anglo-Indian Defence | ... Nf6 | Nc3 e6 | e4 c5 | e5 Ng8 | Nf3 Nc6 | | ∞ |
| Great Snake Variation | ... g6 | e4 e5 | d4 Nf6 | dxe5 Nxe4 | Bd3 Nc5 | | ∞ |
| English Defence | ... b6 | d4 e6 | e4 Bb7 | | | | ∞ |
| Anglo-Dutch Defence | ... f5 | Nf3 Nf6 | g3 g6 | Bg2 Bg7 | O-O O-O | | ∞ |
| Anglo-Scandinavian Defence | ... d5 | cxd5 Qxd5 | Nc3 Qa5 | | | | += |
| Myers Defence | ... g5 | d4 Bg7?! | Bxg5! c5 | Nf3 cxd4 | Nxd4 Qb6 | Nb5 Bxb2?! | +- |
| Halibut Gambit | ... b5 | cxb5 a6 | e4! Bb7 | Nc3 Nf6 | e5 Nd5 | Nf3 e6 | += |

## All possible Black's moves

| Quick Navigation | Na6 a6 a5 | b6 b5 | Nc6 c6 c5 | d6 d5 | e6 e5 | Nf6 f6 f5 | g6 g5 | Nh6 h6 h5 |

## References

* Modern Chess Openings: MCO-14. 1999. Nick de Firmian, Walter Korn. ISBN 0-8129-3084-3.
* Kasparov, Garry, & Keene, Raymond 1989 Batsford chess openings 2. ISBN 0-8050-3409-9.
For explanation of theory tables, see theory table and for notation, see algebraic notation.
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