Chess Opening Theory

Starting position
a b c d e f g h 8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1 a b c d e f g h
Position in Forsyth-Edwards Notation (FEN) rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR
Openings: 1. e4 · King's Pawn opening 1. d4 · Queen's Pawn opening 1. c4 · English opening 1. Nf3 · Zukertort opening 1. f4 - Bird Opening
Moves: [1]

The opening—roughly the first dozen moves—is a fight for space, time, and force.
—Larry Evans^[1]

This is the starting position, the way the pieces are laid out when you first set them up at the start of a game of chess. White moves first, so they have the first choice of how to proceed.

Artists talk about the "tyranny of the blank page," where there are so many possibilities that it is impossible to begin. White has twenty possible first moves. After just five turns, there are 70 trillion possible games of chess. How can anyone decide what to play? Fortunately, in most positions there are good moves and bad moves. The trick is distinguishing one from the other.

The opening is a race for development (force) and control of the centre (space). If you fall too far behind your opponent, then expect a swift attack from their army while yours is still in bed. Moves that help you develop and take space are good, generally. Moves that don't, like unnecessary pawn moves or moving the same piece over and over, are bad^[2]: either mistake gives your opponent the time (tempi) to get ahead in development. Force, space, time.

Now White decides: what is the best, fastest way to develop their pieces and control the centre? There are two possible moves that place a pawn in the centre of the board: 1. e4 and 1. d4.

1. e4, advancing the king's pawn, is the most popular first move at every level of chess, from beginner to grandmaster.

If development is so important, then why are the most popular first moves pawn moves, not piece moves? Doesn't Nimzowitsch warn us against unnecessary pawn moves?

... speed of development is the overriding law. Each piece should be developed with only one move; each and every pawn move—with the exception of those which either establish or support your own centre, or attack that of your opponent—can be considered a waste of time.
—Aron Nimzowitsch^[3]

The answer is that not all of the pieces are ready to develop straight away. The two bishops in particular are stuck behind White's pawns. To let them into the game, White will need to move at least two pawns at minimum (one that's currently on a light square, and one that's currently on a dark square). If White knows they will have to move a pawn at some point for their bishop to develop, then they may as well start with that move before Black gets a chance to control the centre themselves and prevent them from playing it.

Therefore: 1. e4. By moving the pawn away from e2, White creates open diagonals for their king's bishop and queen to access. By clearing out e2, White's bishop can "see" the a6-f1 diagonal and can be developed to one of those squares.

If White only wanted to open the bishop for development, they could have played 1. e3, but 1. e4 has several more advantages over 1. e3. One, it means that, once White moves the d-pawn as well, the queen's bishop's access to the c1-h6 diagonal won't be blocked by a pawn on e3. Two, while there's a white pawn on e4, there won’t be a black pawn on e4 any time soon, which means that the king’s knight can be developed to f3 without fear of getting kicked by a pawn and losing a tempo.

This is central control. Influence over the squares in the centre of the board means you have more safe squares on your side, so it's easier to move your army around. With greater motility, you can more easily target weaknesses in your enemy's camp. Neglect control of the centre, and the advancing enemy will push your pieces away.

Finally, 1. e4 also poses problems for Black's development. It controls the f5 and d5 squares, so if Black hopes to build their own pawn centre with ...d5, then they now need to work a little harder to get a pawn to d5 and keep it there. The pawn threatens to come to e5, and while it can do so, Black's knight won't be safe to go to f6.

1. d4, advancing the queen's pawn, is the second most popular move at all levels. Like 1. e4, this move lets a bishop into the game: this time, the queen's side bishop.

1. d4 prevents Black from getting the useful move ...e5 in straight away, while also controlling the c5-square. It discourages Black from developing the b8 knight to c6, where the pawn can advance to d5 and kick it.

Unlike 1. e4, 1. d4 doesn't open a diagonal for the queen to access. This is no big deal: the queen is in no hurry to develop until more of the army is mobilised, else it is too easy to target. Instead, 1. d4 extends the queen's zone of control forward to the d4 square. After 1. d4, unlike 1. e4, the pawn comes pre-loaded with its own defender. Because the d-pawn is already guarded, attacking it is less forcing and this leads to a different flavour compared to 1. e4 openings.

Conventional wisdom is that, if Black’s position were a castle, 1. d4 players prefer to capture it by digging under the foundations, whereas 1. e4 players like to crash through the front gate on a flaming motorcycle. 1. e4 often leads to sharp, tactical openings, where threats are made and answered each turn and the position often opens up early. 1. d4 tends to lead to closed positions, and has a reputation for being more positional, strategic, and slower burn.

It's no coincidence that 1. e4 and 1. d4 are by far the most popular moves, because they are the most helpful of all possible first moves in allowing White's pieces to join the game. In fact if White can get away with playing both e4 and d4, they will be very happy to do so. Together, 1. e4 and 1. d4 account for about 80% of games. All the other first moves combined appear in about half as many games as 1. d4. If chess opening theory were a solar system, 1. e4 would be Jupiter, 1. d4 Saturn, 1. c4 and 1. Nf3 would be a couple of minor planets, and the rest some dust.

While 1. e4 controls d5, if Black should play ...d5 at some point and White take it, they will no longer have a pawn on the important e4 square. There is a positional advantage to having both central pawns, especially if your opponent has only one. If White could target the centre squares with a flank pawn, they'd have the chance to eliminate one of Black's more valuable pawns with one of their weaker ones.

1. c4, the English opening is the first "minor planet" of opening theory. Controlling the centre from the flank means that White may hold onto their two valuable central pawns for longer. Playing 1. c4 first also ensures that Nc3 may be played without preventing the c-pawn from joining the fight for the centre.

Like 1. e4, 1. c4 controls d5 and allows the queen to develop, but unlike 1. e4 White will still have to play two further pawn moves to help their bishops enter the game.

1. c4 often transposes into 1. d4 openings, as frequently after 1. d4 White would like to play c4 as well, for further control of the centre. Alternatively, after 1. c4 e5, the game resembles a Sicilian defence (1. e4 c5) with colours, and whose turn it is, swapped.

1. f4 is Bird's opening and played for the same reasons. Why is this so much less common than 1. c4? Wheras moving the c-pawn created a diagonal for the queen to control, moving the f-pawn creates a diagonal where the king is vulnerable, and that vulnerability can be leveraged by the opponent. Though 1. f4 controls the e5 square, if Black plays 1...e5 anyway, From's gambit, White has to be carefully else Black will exploit White's weak king's side for a crushing lead. Nevertheless, 1. f4 is feasible for masochists, if they play accurately.

Unlike bishops, knights can enter the game without waiting for a pawn to move out of the way. They also have fewer options for good places to go. For this reason, White may want to begin with a knight move.

1. Nf3 is the Zukertort opening, also known as the Réti opening. It is the second "minor planet" in our survey of first moves.

It's a sophisticated way of stalling for time. White puts the king's knight where it was certainly going to go anyway before they decide on any committal pawn moves. Pawn moves will have to follow soon, however, to allow the bishops to enter the game. 1. Nf3 tends to transpose to openings more commonly seen after 1. d4, 1. c4 or 1. e4.

Since the knight controls the e5 square, Black can hardly answer 1...e5.

• The most common reply is 1...Nf6, which cuts out White's option of 2. e4 too, and typically the game transposes into an English with 2. c4.
• Otherwise, Black may play 1...d5, and White either transposes into a d4 opening with 2. d5 (reaching the same position as after 1. d4 d5 2. Nf3) or plays 2. g3, essentially allowing Black to play a "d4" opening with colours reversed.
• With 1...c5, Black asks White to stop "horsing around" and play 2. e4 after all, transposing into a main line Sicilian defence.

1. Nc3, the van Geet opening, is a lot more unusual. Unlike 1. Nf3, a lot of the time the knight doesn't go to c3 (at least, not until White has moved the c-pawn up the board first). It also doesn't prevent 1...d5, threatening 2...d4, because Black's queen guards the d-pawn. Overall, it is a very off-beat opening without much well-studied theory, which is occasionally to the taste of grandmasters wishing to get their opponents out of their preparation and beat them with experience.

1. Na3? and 1. Nh3? are bad. True, the knights are off the back rank, but they control no further squares than they did on b1 and g1, and none of the important battleground in the centre. To get them "into the game", White will have to move them for a second time, violating opening principles and granting Black a precious tempo.

White realises they must make some pawn moves to get their bishops into the game, but not necessarily 1. d4 or 1. e4. This brings us to the "asteroids" of 1. b3 and 1. g3.

1. b3, preparing 2. Bb2, the Nimzowitsch-Larsen attack; and 1. g3, preparing 2. Bg2, the Hungarian opening; both have the idea of fianchettoing the bishop so that it exerts control over the diagonal running across the board from corner-to-corner.

Black is given the time to build an ideal two-pawn centre with ...d5 and ...e5, but this can still be played because White intends to undermine the centre later, helped by the controls the bishop exerts on the long diagonal. Controlling the centre from afar with the minor pieces, rather than by putting pawns there, was the approach advocated by the hypermodern school of chess.

If 1. b3 and 1. g3 are good, then what about 1. b4 and 1. g4?

1. b4, the Polish opening, also allows 2. Bb2, but unlike 1. b3 the advanced b-pawn can be a target. After 1. b4 e5 (1...e6 2. Bb2 Bxb4?? 3. Bxg7!) 2. Bb2 Bxb4 3. Bxe5 though, the complications are navigable.

The same cannot be said for 1. g4?, the Grob. 1. g4 d5 2. Bg2 Bxg4 and White can't even take the pawn in exchange, because it is defended by the queen. The Grob is the worst possible first move (other than, "Resigns."). Nevertheless, the opening has decent success against amateurs unfamiliar with its trappy lines, e.g. 1. g4 d5 2. Bg2 Bxg4 3. c4 e6 4. Qb3 (threatening Qxb7) b6? 5. cxd5 exd5 6. Bxd5 c6?? 7. Bxf7+ Ke7 8. Bxg8+-.

We're really into the cosmic dust now. Everything else is generally bad: at best simply passing the turn to Black to decide how to play.

This is the full index of all twenty possible opening moves, most of which are not good:

Two-step pawn moves:	a4	b4	c4	d4	e4	f4	g4	h4
One-step pawn moves:	a3	b3	c3	d3	e3	f3	g3	h3
Knight moves:	Na3		Nc3			Nf3		Nh3

I see only one move ahead, but always the best move.
—attributed to Charles Jaffe, New York amateur^[4]

Most popular opening lines include:

	1	2	3	4	5	6	7	8	9
Open game (Spanish game)	e4 e5	Nf3 Nc6	Bb5 a6	Ba4 Nf6	O-O Be7	Re1 b5	Bb3 d6	c3 O-O	h3 Na5
Sicilian defence	... c5	Nf3 d6	d4 cxd4	Nxd4 Nf6	Nc3 a6	Be3 e5	Nb3 Be6	f3 h5	Nd5 Bxd5
French defence	... e6	d4 d5	Nc3 Bb4	e5 c5	a3 Bxc3+	bxc3 Ne7	Qg4 O-O	Bd3 Nbc6	Qh5 Ng6
Caro-Kann defence	... c6	d4 d5	e5 Bf5	Nf3 e6	Be2 Nd7	O-O Ne7	Nbd2 h6	Nb3 g5	Ne1 Qc7
Closed game (Slav defence)	d4 d5	c4 c6	Nc3 Nf6	Nf3 e6	Bg5 h6	Bh4 dxc4	e4 g5	Bg3 b5	Be2 Bb7
Indian defence	... Nf6	c4 e6	Nf3 b6	g3 Ba6	b3 Bb4+	Bd2 Be7	Bg2 c6	Bc3 d5	Ne5 Nfd7
Zukertort opening	Nf3 Nf6	c4 g6	Nc3 Bg7
English opening	c4 e5	Nc3 Nf6	Nf3
	... Nf6	Nc3 g6

The most popular full first moves (one move for White and Black) are:

Popularity of Top 25 Full Moves

Move	Popularity	Variation
1. e4 c5	19.0%	Sicilian Defense
1. d4 Nf6	17.1	Indian Game
1. e4 e5	12.6	Open Game
1. d4 d5	9.4	Closed Game (Queen's Gambit, etc.)
1. e4 e6	6.0	French Defense
1. e4 c6	3.8	Caro-Kann Defense
1. Nf3 Nf6	3.4	flexible (including Queen's Pawn or English systems)
1. Nf3 d5	2.3	flexible (King's Indian Attack, Queen's Gambit, Réti, etc.)
1. e4 d5	2.0	Scandinavian Defense
1. e4 d6	1.9	Pirc Defense
1. d4 e6	1.8	the flexible Horwitz (Queen's Pawn, French, etc.)
1. c4 Nf6	1.8	Anglo-Indian Defense
1. e4 g6	1.5	Modern (Robatsch) Defense
1. c4 e5	1.5	Reversed Sicilian
1. d4 g6	1.0	Modern Defense (Queen’s Pawn)
1. e4 Nf6	1.0	Alekhine Defense
1. d4 d6	1.0	flexible (Modern, Pirc, King's Indian, Old Indian)
1. Nf3 c5	0.9	Sicilian, Réti
1. d4 f5	0.9	Dutch Defense
1. c4 e6	0.9	English
1. c4 c5	0.7	Symmetrical English
1. d4 c5	0.7	Old Benoni Defense
1. c4 g6	0.5	English Great Snake
1. c4 c6	0.5	English, Caro-Kann, Slav, or Réti
1. Nf3 g6	0.5	Réti
everything else	7.2

Wikipedia has related information at Chess opening.

General opening texts:

• 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.