Chess Opening Theory

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What is 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

Yes, it is possible! But only if your friend doesn't see it coming. This makes sense, because if there was a fool-proof way to win the game in four moves, no one would play chess.

The trick is to carry out a lightning attack on the weak f7 pawn. It's a weak pawn because it's defended only by the king. If you can attack it with two pieces while it's defended by only one, you've won it for free.

White's first move is 1.e4. The queen and f1-bishop, which were stuck on the back rank, can now be developed. Developing a piece means moving it off the back rank and putting it somewhere more useful. The plan is to quickly develop the queen and f1-bishop in such a way that they both attack that f7 pawn.

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

Then White brings out the f1-bishop, as planned: 2.Bc4. Notice how it attacks the weak f7 pawn. It's now got one attacker and one defender.

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

White makes a bold queen move: 3.Qh5. That's two attackers on f7, and still only one defender.

Black notices that the queen on h5 is threatening the pawn on e5, and so defends it with the innocent 3...Nc6?? (diagram left).

Solid white.svg a b c d e f g h Solid white.svg
8 a8 black rook b8 black king c8 black bishop d8 black queen e8 black king f8 black king g8 black knight h8 black rook 8
7 a7 black pawn b7 black pawn c7 black pawn d7 black pawn e7 black king f7 black pawn g7 black pawn h7 black pawn 7
6 a6 black king b6 black king c6 black knight d6 black king e6 ur f6 black king g6 ul h6 black king 6
5 a5 black king b5 black king c5 black bishop d5 ur e5 black pawn f5 black king g5 black king h5 white queen 5
4 a4 black king b4 black king c4 white bishop d4 black king e4 white pawn f4 black king g4 black king h4 black king 4
3 a3 black king b3 black king c3 black king d3 black king e3 black king f3 black king g3 black king h3 black king 3
2 a2 white pawn b2 white pawn c2 white pawn d2 white pawn e2 black king f2 white pawn g2 white pawn h2 white pawn 2
1 a1 white rook b1 white knight c1 white bishop d1 black king e1 white king f1 black king g1 white knight h1 white rook 1
Solid white.svg a b c d e f g h Solid white.svg
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#.
Solid white.svg a b c d e f g h Solid white.svg
8 a8 black rook b8 black knight c8 black bishop d8 black king e8 black king f8 black king g8 black knight h8 black rook 8
7 a7 black pawn b7 black pawn c7 black pawn d7 black pawn e7 black queen f7 black pawn g7 black pawn h7 black pawn 7
6 a6 black king b6 black king c6 black king d6 black king e6 black king f6 black king g6 black king h6 black king 6
5 a5 black king b5 black king c5 black bishop d5 black king e5 black pawn f5 black king g5 black king h5 white queen 5
4 a4 black king b4 black king c4 white bishop d4 black king e4 white pawn f4 black king g4 black king h4 black king 4
3 a3 black king b3 black king c3 black king d3 black king e3 black king f3 black king g3 black king h3 black king 3
2 a2 white pawn b2 white pawn c2 white pawn d2 white pawn e2 black king f2 white pawn g2 white pawn h2 white pawn 2
1 a1 white rook b1 white knight c1 white bishop d1 black king e1 white king f1 black king g1 white knight h1 white rook 1
Solid white.svg a b c d e f g h Solid white.svg
Much better idea. Black will now get the move ...Nf6 for free, because White's queen will have to move.

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 (diagram right). Now, what does White's queen think she's doing on h5? Everything she can attack is defended. She can't make any more progress. If she was a hockey player, she would be offside.

But more importantly, Black is going to play ...Nf6 next. Importantly, it will gain time on the queen. Black is already a bit better. The first sentence deserves to be in large letters:

Black is going to play ...Nf6 next!

Once you understand the importance of this little fact, you understand what Chess Opening Theory is. To explain it, we need to explain Tempo.

Tempo

Solid white.svg a b c d e f g h Solid white.svg
8 a8 black rook b8 black knight c8 black bishop d8 black king e8 black king f8 black king g8 black king h8 black rook 8
7 a7 black pawn b7 black pawn c7 black pawn d7 black pawn e7 black queen f7 black pawn g7 black pawn h7 black pawn 7
6 a6 black king b6 black king c6 black king d6 black king e6 black king f6 black knight g6 black king h6 black king 6
5 a5 black king b5 black king c5 black bishop d5 black king e5 black pawn f5 black king g5 black king h5 white queen 5
4 a4 black king b4 black king c4 white bishop d4 black king e4 white pawn f4 black king g4 black king h4 black king 4
3 a3 black king b3 black king c3 black king d3 white pawn e3 black king f3 black king g3 black king h3 black king 3
2 a2 white pawn b2 white pawn c2 white pawn d2 black king e2 black king f2 white pawn g2 white pawn h2 white pawn 2
1 a1 white rook b1 white knight c1 white bishop d1 black king e1 white king f1 black king g1 white knight h1 white rook 1
Solid white.svg a b c d e f g h Solid white.svg
Black has made the move she wanted to make anyway, which was ...Nf6. White would like to play a useful move like Nf3 too, but because her queen is attacked, she doesn't have time. She has lost 1 tempo.

Chess is a turn-based game, but it's an unusual kind of turn-based game: you can only move one piece each turn. If your queen is doing something this turn, bad luck, the rest of your pieces have to stay put. In business-speak, there's an opportunity cost to moving the queen.

So it goes without saying that each turn is a precious commodity, which we call a tempo. A tempo is an opportunity to move something.

Shouldn't White and Black always possess the same number of tempos, because Black gets one turn for every turn White gets? Not quite.

If your queen gets attacked by a knight, like White's queen in the diagram on the right, you've got to move it or lose it. Instead of developing another piece, you've got to waste this tempo re-locating a piece you'd already developed. Of course, there are exceptions to every rule, just like in the Legal's mate. So Black's move ...Nf6 is basically a free move. Chess players would say "Black has gained a tempo on the queen".

So when chess books tell you that Qh5 is an easily parried threat, that's only half the story. Isn't Black's move ...Nf6 also an easily parried threat? The big difference is this: Qh5 is an easily parried threat that also loses you a tempo and doesn't do much useful, whereas ...Nf6 is an easily parried threat that gains a tempo and develops a piece.

And that right there is opening theory in microcosm. In the opening, development is everything. To develop, you need tempos. How do I develop my pieces so that I don't lose any tempos along the way, and if possible I gain tempos at my opponent's expense? The answer to that question is Chess Opening Theory.

The perfect chess opening is one where you develop every piece in a single move to its best possible square, and then leave it there. (Lots of players have searched for the perfect chess opening. Sadly, it doesn't exist.)

Things like territory (controlling lots of squares with your pieces), structure (keeping your pieces and pawns supporting each other) and even material (how many pieces you've got left on the board) can all take a back seat. If you want to know the real reason the grandmasters are playing one opening move instead of another, think development, and think tempos.

White's first move

1.e4
a b c d e f g h
8 {{{square}}} black rook {{{square}}} black knight {{{square}}} black bishop {{{square}}} black queen {{{square}}} black king {{{square}}} black bishop {{{square}}} black knight {{{square}}} black rook 8
7 {{{square}}} black pawn {{{square}}} black pawn {{{square}}} black pawn {{{square}}} black pawn {{{square}}} black pawn {{{square}}} black pawn {{{square}}} black pawn {{{square}}} black pawn 7
6 {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king 6
5 {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king 5
4 {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} white pawn {{{square}}} black king {{{square}}} black king {{{square}}} black king 4
3 {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king 3
2 {{{square}}} white pawn {{{square}}} white pawn {{{square}}} white pawn {{{square}}} white pawn {{{square}}} black king {{{square}}} white pawn {{{square}}} white pawn {{{square}}} white pawn 2
1 {{{square}}} white rook {{{square}}} white knight {{{square}}} white bishop {{{square}}} white queen {{{square}}} white king {{{square}}} white bishop {{{square}}} white knight {{{square}}} white rook 1
a b c d e f g h
I see only one move ahead, but always the best move.
—attributed to Charles Jaffe, New York amateur

King's Pawn Opening

The move 1.e4, called the King's Pawn Opening, is the most popular initial move at every level of chess from beginner to grandmaster. Even if you aren't trying to checkmate Black in four moves, letting the queen and bishop out is a good thing to do.

You might hear people recommending 1.e4 because it controls the squares d5 and f5. Well, sort of, but that's a bit vague and abstract really. Black could just take them away again by playing 1...e6 if she wanted to. Think development and think tempos! The most important square White controls by playing 1.e4 is in fact... the e4 square itself. Having a white pawn on that square means there's never going to be a black pawn on that square, which means the g1 knight can be developed to f3 without fear of getting kicked by a pawn and losing a tempo.

And 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 the g8 knight if White can simply advance the pawn to e5. The simplest way for Black to fix this problem would be to copy White and play 1...e5 in response.

So why would you ever play anything other than 1.e4 - and why would Black ever meet it with anything other than ...e5? It took chess players a few hundred years to realise the answer to that question:

If Black wants to play ...e5, but instead of 1.e4 I play a move that attacks the e5 square, Black can't play ...e5 any more!

And so they invented:

Queen's Pawn Opening

1.d4
a b c d e f g h
8 {{{square}}} black rook {{{square}}} black knight {{{square}}} black bishop {{{square}}} black queen {{{square}}} black king {{{square}}} black bishop {{{square}}} black knight {{{square}}} black rook 8
7 {{{square}}} black pawn {{{square}}} black pawn {{{square}}} black pawn {{{square}}} black pawn {{{square}}} black pawn {{{square}}} black pawn {{{square}}} black pawn {{{square}}} black pawn 7
6 {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king 6
5 {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king 5
4 {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} white pawn {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king 4
3 {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king {{{square}}} black king 3
2 {{{square}}} white pawn {{{square}}} white pawn {{{square}}} white pawn {{{square}}} black king {{{square}}} white pawn {{{square}}} white pawn {{{square}}} white pawn {{{square}}} white pawn 2
1 {{{square}}} white rook {{{square}}} white knight {{{square}}} white bishop {{{square}}} white queen {{{square}}} white king {{{square}}} white bishop {{{square}}} white knight {{{square}}} white rook 1
a b c d e f g h

1.d4, called the Queen's Pawn Opening, is the 2nd most popular initial move, 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. In the opening theory solar system you have Planet 1.e4, Planet 1.d4, and some dust.

1.d4 is played to prevent* Black from getting the useful move ...e5 in straight away. It also discourages Black from developing the b8 knight to c6, where the pawn can advance to d5 and kick it.

White isn't necessarily interested in developing the c1-bishop straight away - it tends to be the least important piece to develop. 1.d4 is more about slowing down Black's development than speeding up White's.

If Black retaliates in kind with 1...d5 to prevent** White from following up with 2.e4, White can instead play 2.c4, the Queen's Gambit, hoping to divert Black's pawn from its job of attacking e4. The Queen's Gambit is the champagne and caviar of White openings and is a huge reason for the popularity of 1.d4.

A note on the word gambit: a gambit is a specific kind of opening in which material (pawns or, rarely, larger pieces) is sacrificed to gain an advantage in development and tempos. Always think development and tempos! 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!

*In fact, 1.d4 e5 is a real opening, but not a very good one.

**In fact, 1.d4 d5 2.e4 is also a real opening, but a notoriously, iconically bad one. So naturally, no-one plays it. it has thousands of passionate advocates on the internet.

How do I choose between 1.e4 and 1.d4?

Conventional wisdom is that 1.d4 players like to capture the castle by digging under the foundations, whereas 1.e4 players like to crash through the front gate on a flaming motorcycle.

This is a bit of an over-generalisation. You're not going to get put into a four-move checkmate by 1.d4 player, but if you play bad moves you'll get attacked with every bit as much vigour. 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 hit by a tactical avalanche while playing a "strategic" Queen's Gambit.

Other opening moves

  • 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.
  • 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 too, basically just because humans love to name things.

All possible initial moves

Quick
Navigation
a4
a3
Na3
b4
b3
c4
c3
Nc3
d4
d3
e4
e3
f4
f3
Nf3
g4
g3
h4
h3
Nh3

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

Statistics

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

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.

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

For explanation of theory tables see theory table and for notation see algebraic notation

1 2 3 4 5 6
Sicilian Defence e4
c5
Nf3
d6
d4
cxd4
Nxd4
Nf6
Nc3
a6
Be2
e6
=
Ruy Lopez ...
e5
Nf3
Nc6
Bb5
a6
Ba4
Nf6
O-O
Be7
Re1
b5
=
King's Indian Defence d4
Nf6
c4
g6
Nc3
Bg7
e4
d6
Nf3
O-O
Be2
e5
=
Queen's Gambit Declined ...
d5
c4
e6
Nc3
Nf6
Bg5
Be7
e3
O-O
Nf3
Nbd7
=
King's Indian Attack Nf3
d5
g3
Nf6
Bg2
c6
O-O
Bg4
d3
Nbd7
Nbd2
e5
=


References

  • 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.