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Chess Opening Theory


In chess, unlike tennis, it is not possible to win by serving an ace.
—Irving Chernev, chess writer

So, you've learned the rules of chess. You've learned that moving your pieces off the back row and controlling territory is a good plan, and letting lots of your pieces get captured for free is a bad one. (If you have doubts about any of that, head over to the Chess Wikibook first!)

Now it's time to answer that $64,000 question that's on the tip of every new chess player's tongue. The question that cuts right to the heart of what it means to be a competitive board game player:

How can I beat my friend in like, four moves?

Beating your friend in four moves

The good news is it's not a myth - there really is a way to checkmate in four moves! The bad news is that an opponent who sees it coming can foil your plans. Which makes sense, because if there was a fool-proof way to win the game in four moves, no one would play chess.

Once you know the four-move checkmate, it's obvious when someone's trying to spring it on you. And a failed four-move checkmate, like a failed banzai charge, leaves your forces over-extended and vulnerable.

If you don't want to be left with over-extended and vulnerable forces, what should you do instead?

The short answer is "it depends what your opponent does." The long answer would require a whole library of books - or a single easy-to-navigate Wikibook, which is what you now have in front of you!

Why the four-move checkmate doesn't work

Let's look at that four-move checkmate. White's first move (we will refer to the players by the colour of their pieces) is 1.e4.

  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 position after 1.e4. The White bishop and queen can now get out and do some damage.

The move 1.e4 clears the e2 square. The queen and f1-bishop, which were stuck on the back row, can now move out into the centre of the board and contribute to the game. Both of those pieces are important to the four-move checkmate.

Black replies by copying White: 1...e5.

Then White brings out the bishop that was freed by 1.e4, and puts it on c4 where it attacks Black's vulnerable pawn on f7: 2.Bc4.

Black isn't entirely sure what's going on, and so copies White again: 2...Bc5.

Then White makes a bold queen move: 3.Qh5. This attacks the Black pawn on e5.

Now Black can't copy White any more, because 3...Qh4?? would lose the queen for nothing. So instead Black defends the threatened e5 pawn with the innocent 3...Nc6.

  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  
Black has failed to deal with the lightning attack on f7 by the White bishop and queen, and is about to get four-move-checkmated with 4.Qxf7#.

But White's real target wasn't e5, it was f7! White plays 4.Qxf7#. The # stands for checkmate. Oops!

Where did Black go wrong here? Let's allow Black to take back the move 3...Nc6 and replace it with 3...Qe7! which defends the f7 and e5 pawns simultaneously. Now, what does White's queen think she's doing on h5? Everything she can attack is defended, and she's going to get evicted as soon as Black plays ...Nf6.

So White decides to take back 3.Qh5 and replace it with a less banzai-ish move 3.Nf3. Now White is playing the opening sensibly! Black still has an attack on the e5 pawn to worry about, but White's knight is going to be well placed even after Black defends the pawn.

Not only that, but White has removed both pieces from between the king and h1-rook, which means kingside castling has become an option. If you ever find yourself in the first few moves of a chess game with no idea what you're supposed to be doing, aiming towards kingside castling is a solid plan 99% of the time.

So although White's third move was an over-eager one, it looks as though White was onto something by playing 1.e4 and 2.Bc4...

White's first move

Sure enough, the move 1.e4, called the King's Pawn Opening, is the single most popular initial move. That's true at every level of chess from beginner to grandmaster.

If we fixate on castling kingside as soon as possible, we can see that advancing either the e-pawn or the g-pawn is essential. The bishop on f1 can't go anywhere until you do. 1.e4 has a number of other advantages:

  • It frees the queen too - she likes to have breathing space even if she isn't planning to charge out to h5!
  • It avoids placing an obstruction on the diagonal between c1 and h6. This is important because at some point White will want to develop the c1-bishop too. 1.e3 would not have this advantage.
  • It contributes towards White's control of the centre squares. The pawn is now attacking d5 and f5.

A quick note about navigating this Wikibook: each page in this Wikibook corresponds to a single position, which will be shown in the diagram on that page. You are currently looking at the page for the initial position - the way the pieces are laid out when you first set them up on the board. One or more links will appear in the main body of the text, like this one: 1.e4. These representing possible moves from that position. Choose a move, click it, and reach a new position. Sometimes a list of common moves will appear under the page diagram, and if you find reading words about chess positions boring, you can pick the next move from that list too.

So what alternatives to 1.e4 exist?

There are two other reasonable moves with which White can make a start on Operation Castle As Quickly As Possible: 1.Nf3 and 1.g3.

  • 1.Nf3 is the 3rd most popular initial move. It's a sophisticated way of stalling for time. White reckons that Nf3 will almost certainly be a useful move sooner or later, whereas every pawn move is an irrevocable commitment. 1.Nf3 has the benefit of cutting out the reply 1...e5 by Black, which is a move that Black likes to play for all the same reasons that White likes to play 1.e4.
  • 1.g3 is the 5th most popular initial move. It doesn't immediately influence the centre, but White plans to follow up with Bg2 which does. The hypermodern school of opening theory, (ironically) most influential in the 1920s and 1930s, was all about controlling the centre with pieces rather than occupying it with pawns.

Queen's Pawn Opening

The idea of making it difficult for Black to play the move ...e5 immediately suggests another possibility: 1.d4, called the Queen's Pawn Opening. This is the 2nd most popular initial move, but it's in the same ballpark as 1.e4 in terms of games played. All the other legal moves combined appear in about half as many games as 1.d4. You could describe the opening theory solar system as consisting of Planet e4, Planet d4, and some dust.

Benefits of the Queen's Pawn Opening:

  • It releases the c1-bishop. We've already seen that releasing bishops is a good idea.
  • It controls some central squares, which is also a good idea.
  • It discourages 1...e5. In fact, 1.d4 e5 is a real opening, but not one with a terribly good reputation. It's a gambit, which is a specific kind of opening in which material (pawns or, rarely, larger pieces) is sacrificed to gain an advantage in position. If there's no material sacrificed, it's not a gambit. "Opening gambit" is a tautology. Despite what the musical CHESS may have told you, not every opening is a gambit!
  • If Black copies with 1...d5, White can then play 2.c4, the Queen's Gambit, hoping to draw Black's pawn away from the centre. The Queen's Gambit is the champagne and caviar of White openings and is a huge reason for the popularity of 1.d4. The mirror-image King's Gambit, 1.e4 e5 2.f4, has a far sketchier reputation.

Planet e4 or Planet d4?

Nearly every serious player has, at some point, had to decide whether 1.e4 or 1.d4 is more to their taste. How do they choose? Lots of people will try to tell you that e4 openings are swashbuckling and tactical, whereas d4 openings are sedate and strategic. This is far too broad a generalisation. You're not going to get put into a four-move checkmate by a player who opens 1.d4, but that doesn't make you any more likely to get away with playing terrible moves. Read Irving Chernyev's instructional books, or the collected games of the great inter-war players Lasker, Capablanca and Alekhine, and you'll soon discover how easy it is to get buried under a tactical avalanche while playing a "sedate" Queen's Gambit.


Away from Planets e4 and d4, there are a few more asteroids of note. 1.Nf3 and 1.g3 have been mentioned already.

  • 1.c4, the English Opening, 4th most popular move. White frees the queen, discourages the move 1...d5, and makes absolutely sure that the c-pawn won't get stuck on c2 behind a knight on c3. The resulting positions have more of a 1.d4 character than an 1.e4 character, and indeed the move d4 often follows later.
  • 1.f4 is Bird's Opening, the same idea as the English but on the kingside. It doesn't prevent 1...e5, incidentally. 1.f4 e5 is the well-known From Gambit and contains a fiendish trap for an unwary White player.
  • 1.b3 is Larsen's Opening, a hypermodern idea akin to 1.g3. Instead of preparing to castle kingside, White tries to scare Black out of it by pointing a bishop at g7.
  • 1.Nc3 is the Dunst Opening. White makes absolutely sure the c-pawn will get stuck on c2. There are many possible transpositions after 1.Nc3. A transposition just means playing the same moves in a different order. Where a position A is most commonly reached through opening B, it will be classified under opening B. If you reach it through opening C, you will have transposed from opening C to opening B. For example, 1.Nc3 e5 2.e4 is a transposition to the Vienna Game, because the Vienna Game move order is 1.e4 e5 2.Nc3.
  • 1.b4 is the Sokolsky Opening. White reckons Larsen's opening can be improved upon by moving the pawn further forward. The pawn controls more space on b4 instead of b3, but is more vulnerable - and the space it controls is not space that typically needs to be controlled. It's a sort of fashionably eccentric opening for people who wear bow ties.

The remaining 11 legal moves all have names, because humans love to name things, but they aren't serious attempts to gain an advantage. They exist for the same reason that collective nouns for animals exist: as collector's items for intellectuals.

All possible initial moves


Encyclopaedia of Chess Openings

ECO volume A : English Opening, Benoni Defence, Dutch Defence, King's Indian Attack, Benko Gambit, Old Indian, Bird's Opening
ECO volume B : Sicilian Defence, Caro-Kann Defence, Pirc Defence, Modern Defence, Alekhine's Defence, Scandinavian Defence
ECO volume C : Ruy Lopez, French Defence, Petrov's Defence, King's Gambit, Philidor Defence, Giuoco Piano, Two Knights Defence, Scotch Game
ECO volume D : Queen's Gambit Declined, Queen's Gambit Accepted, Slav Defence, Tarrasch Defence, Grünfeld Defence, Queen's Pawn
ECO volume E : Nimzo-Indian Defence, Queen's Indian Defence, King's Indian Defence, Catalan Opening, Bogo-Indian Defence


Approximate chances: White win 39%, Draw 32%, Black win 29%
Estimated first move popularity:
e4 43%, d4 37%, Nf3 10%, c4 8%, g3 1%, b3 0.3%, f4 0.2%, Nc3 0.1%, b4 0.1%, all other moves less than 0.1%.

Using this wikibook

You can use the Encyclopedia of Chess Openings (ECO) code index if you prefer to navigate to positions that way.

Head over to the Great Big Opening Survey page to see a list of the opening lines that this Wikibook ought to be covering if it isn't already. Please help add the ones that are missing!

When contributing to this Wikibook, please follow the conventions for organization.

Theory table


  • Batsford Chess Openings 2 (1989, 1994). Garry Kasparov, Raymond Keene. ISBN 0-8050-3409-9.
  • Nunn's Chess Openings. 1999. John Nunn (Editor), Graham Burgess, John Emms, Joe Gallagher. ISBN 1-8574-4221-0.