Chess Opening Theory/1. e4

1. e4 · King's Pawn Opening
The move 1. e4, the King's Pawn Opening, is the most popular first move at all levels of the game and was the favorite opening move of world champion Bobby Fischer, who called it 'best by test.' White's assertive opening move opens lines for the queen and the king's bishop (a good thing to do).

1. e4 also fights for control of d5 and f5, which might or might not be relevant later, because Black if they wanted to could just take those squares away again by playing 1...e6. If White wants to develop some pieces, the most important square they control by playing 1. e4 is, in fact, the e4 square itself. As long as there's a white pawn on e4, there can't be a black pawn on e4, which means White's g1-knight can be developed to f3 without fear of getting kicked away by a pawn and losing a tempo.

Just as White indirectly claims the f3 square by playing e4, Black has to bear in mind that f6 will not be a safe square for Black's g8-knight if White can simply advance their e4-pawn to e5. The simplest way for Black to fix this problem would be to copy White and play 1...e5 in response. White may also be dreaming of playing d4 next move, creating a strong 'classical' center, and 1...e5 by Black interferes with that plan.

Openings with 1. e4 are traditionally considered more sharp and attacking than those with 1. d4, but this is an extreme generalization, and both players will have many more opportunities to influence the type of position that appears. 1. e4 positions are in general more forcing than 1. d4 positions, meaning that the number of good moves in any position is lower because your opponent is threatening to do something horrid to you, which can make them easier for beginners to understand.

Black's responses
Games in which Black responds with 1...e5 are called Open Games, whereas games with Black responding by any other move are known as Semi-Open Games (or Asymmetrical King's Pawn Games). It's useful to think of black's responses to 1. e4 as motivated by one of the following counterplans:


 * 1) Establish a pawn on e5, securing a share of the centre for Black (1...e5).
 * 2) Establish a pawn on d5, securing a share of the centre for Black (1...c6 or 1...e6).
 * 3) Attack White's e-pawn immediately (1...d5 or 1...Nf6).
 * 4) Leave White's e-pawn alone but prevent white from achieving the classical centre with e4 and d4 (1...e5 or 1...c5).
 * 5) Ignore what White is doing, allow White to build the classical centre and deal with it later (1...d6, 1...g6, 1...Nc6, 1...b6, or 1...a6).

Plan 1
Plan 1 (pawn on e5, share centre) can be carried out very simply with 1...e5. Black sees what White has and wants the same thing. However, White's argument is that moving first in a symmetrical position is eventually going to favour the player moving first.

Plan 2
Plan 2 (pawn on d5, share centre) is the motivation behind 1...c6, the Caro-Kann Defence, and 1...e6, the French Defence. If Black tries to put a pawn on d5 immediately, White will capture it, so in order to maintain a pawn on d5 Black needs to be able to recapture with a pawn from either c6 or e6.

Plan 3
Plan 3 (attack White's e-pawn) leads to 1...d5, the Scandinavian Defence, and 1...Nf6, the Alekhine Defence.

Plan 4
Plan 4 (prevent White's e4 & d4) is a pleasant side effect of 1...e5 (mentioned above for Plan 1).

But, with 1...c5, the Sicilian Defence, Black can prevent White's d4 advance and also create an asymmetrical position of attack and counter-attack. The Sicilian and 1...e5 are the most popular replies to 1. e4 among top players.

Plan 5
There are multiple ways of carrying out Plan 5 (ignore White's centre, deal with it later).
 * 1...g6, the Modern Defence, signals Black's intention to put a bishop on g7 controlling a swathe of the centre, before deciding on further action.
 * 1...d6 is the Pirc Defence, a hypermodern response to White's 1. e4.

In the Pirc Defence, the move 1...d6 prepares the move 2...Nf6. In Alekhine Defence (mentioned above for Plan 3), 1...Nf6 can be met by 2. e5 kicking the knight back. But, in the Pirc, after 1...d6 2. d4 Nf6, the move 3. e5 doesn't work because of 3...dxe5 4. dxe5 Qxd1+ 5. Kxd1 Ng4! forking the pawns on e5 and f2.

So instead, White's usual move to defend the e-pawn is 3. Nc3. Now, White's d-pawn is vulnerable to the advances 3...c5 or 3...e5 because neither White's e-pawn nor c-pawn can defend it.

Plan 5 also covers a number of fringe options.
 * 1...Nc6, the Nimzowitsch Defence. Black is able to react to 2. d4 with a thrust of either the d-pawn or e-pawn.


 * 1...b6 is a similar idea to 1...g6 but doesn't have the benefit of preparing kingside castling.


 * 1...a6 is mostly famous for having been played by Tony Miles against then World Champion Anatoly Karpov, and having thus acquired the name St. George Defence. Often Black will follow up with 2...b5, expanding on the queenside.

Rare Responses
Other rare responses include:
 * 1...f5?, the Fred Defence/Duras Gambit. This is not too good of an idea. Black gets a lead in development but little compensation for the sacrificed pawn after 2. exf5 Nf6. This can lead to another variation of the Fool's Mate after 2. exf5 g5?? 3. Qh5#
 * 1...f6?, the Barnes Defence. A rare move that is not a good idea, as it removes the f6 square for the knight and weakens the kingside. Even so, Thomas Wilson Barnes (after whom it is named) beat Paul Morphy, one of the most influential grandmasters in the 19th century, with this opening. Its only benefit is that it gets out of theory.
 * 1...g5?, the Borg Defence (opposite of Grob) is another option Black has, however it is a bad one because it does weaken the kingside severely. The g5-pawn can serve as a hook for White (h4) later on. This also can lead to a Fool's Mate for Black.
 * 1...a5?!, the Ware Defence is equally weak as 1...h5. It just wastes a tempo.
 * 1...h5?!, the Pickering Defence simply wastes a tempo and weakens Black's position.
 * 1...h6?!, the Carr Defence, is another time-wasting move, but it usually transposes into the Borg Defence anyways after 2. d4 g5.
 * 1...Na6?! develops the b8-knight to an inferior square.
 * 1...Nh6?! develops the g8-knight to an inferior square.
 * 1...b5? simply loses a pawn to 2. Bxb5.

Statistics

 * Approximate chances
 * White win 39%, Draw 29%, Black win 32%.


 * Estimated next move popularity
 * c5 39%, e5 26%, e6 12%, c6 8%, d5 4%, d6 4%, g6 3%, Nf6 2%, Nc6 1%, b6 1%, other moves less than 0.5%.

Theory table
1. e4