# Chess Opening Theory/Great Big Opening Survey

## Introduction

This page is intended as an extended contents page of the Chess Opening Theory Wikibook project.

Not all openings are created equal. A 7th move variation in the Najdorf Sicilian needs its own page in this Wikibook. A 7th move variation in the Potato Variation of the Réti Opening does not.

But this is difficult to see when you're navigating through the book one move at a time starting from the initial position. One blue link looks the same as another. It's easy to get lost in the forest.

The rule for including an opening in the Great Big Opening Survey is simple:

Does your database have at least 100 games with this branch for every 50,000 games that start 1.e4?

In other words, take the number of 1.e4 games in the database and divide it by 500. That number is the cut-off for inclusion in this survey. (As this Wikibook grows, this cutoff can be lowered!)

The Opening Explorer at http://www.chessgames.com/perl/explorer, for example, has 396,710 1.e4 games as of 10th January 2018. So an opening line must appear in at least 396710 / 500 = 793 games in that database to be included.

Regardless of the size of your database, if you look at the frequency of White's initial moves this magic number should fall between 1.Nc3 and 1.b4 - between the unfashionable and the eccentric. If it falls below 1.b4, your database is probably not selective enough in what it considers high-level games. If it falls above 1.Nc3, your database might be out of date.

Because the Great Big Opening Survey is a very long list, an abridged version is shown, representing 10 times less "resolution", i.e. instead of appearing 100 times for every 50,000 1.e4 games, an opening must appear 1,000 times.

For every line given below, the last move that appears in the text is the last move that qualifies as an independent line under the above criteria. This move will be part of a bold blue link. Intermediate positions will be blue-linked but not bold.

Where a move is underlined, that move dips below the cut-off for inclusion but the resulting position does not, due to transpositions. Some lines have been extended beyond the cutoff, either to separate two lines that would otherwise appear to transpose into each other, or to merge two lines that were clearly converging on the same position.

## Abridged list (1,000 games per 50,000 1.e4 games)

### 1.Nf3 (1 line)

• 1...Nf6 (for 1...c5 2.c4 see 1.c4 > Symmetrical English; for 1...c5 2.e4 see 1.e4 > Sicilian Defence; for 1...d5 2.d4 see 1.d4 > Queen's Gambit), then

## Full list (100 games per 50,000 1.e4 games)

Abbreviations used below:

NSE = Not significant enough

NIE = Not independent enough. This indicates a line that appears to be above the cutoff, but would fall below it if subsequent transpositions were taken out.

alt. = Alternative, used to indicate an independent sideline

l/o = leaving out. This is a variation characterised by the leaving out of a move that appears in the main line. The variation is independent as long as the move left out is left out. If it gets played later, it may transpose back to the main line.

r/o = reserving option of.

[Pa-11] - these are Pachinko Index codes, developed specially for this Wikibook.

### 1.e4

#### [Kp] Mutual King's Pawn: 1.e4 e5, then

(This is highly dependent on what years your database covers. Many of the following alternatives to the Ruy Lopez show up in databases of "historic" games far more than in current master play.)

#### [Ka] King's Indian Attack Island

There are many ways to reach King's Indian Attack Island. Most of the possible replies to 1.e4 have a King's Indian Attack variation of some sort. The lines found on King's Indian Attack Island have more in common with each other than with the openings they originated from.

### 1.d4

#### [Qs] 1.d4 - everything else

• 1.d4 e6 2.c4 (for 2.Nf3 see Dutch Defence after 2...f5, see 1...Nf6 after 2...Nf6 or see 1...d5 after 2...d5; for 2.e4 see French Defence), then
• [Qs-11] English Defence: 2...b6 many many independent lines result from this, none of them significant enough. Black may avoid transposing out by avoiding ...Nf6, thus reserving the option of ...f5. White may avoid transposing out by avoiding e3, thus reserving the option of e4.
• (Keres (Kangaroo) Defence 2...Bb4+ is NIE due to most lines transposing to Nimzo- or Bogo-Indians; [Qs-2] is reserved for it anyway)
• (for 2...Nf6 see 1...Nf6)
• (for 2...d5 see 1...d5)
• (for 2...f5 see Dutch Defence)
• Dutch Defence: 1.d4 f5 then
• Old Indian: 1.d4 d6, then the independent line is the [Qs-61] Wade Defence: 2.Nf3 Bg4 (everything else transposes out as follows:
• Neo-Old Indian: 2.Nf3 then 2...g6 3.c4 Bg7 4.Nc3 is NIE due to 4...Nf6 transposing to King's Indian Defence and 4...Nd7 5.e4 transposing to Modern Averbakh; for 2...Nf6 see 2.c4 after 3.c4 or see Fianchetto King's Indian after 3.g3 g6 4.Bg2 Bg7 (or 2...g6 3.g3 Bg7 4.Bg2 Nf6)
• for 2.c4 see 1...Nf6 2.c4, Old Indian after 2...Nf6 or see Modern, Averbakh after 2...g6 3.Nc3 Bg7 4.e4; Pillsbury Defence 2...e5 is NIE due to 3.Nc3 transposing to King's English
• for 2.e4 see Pirc Defence)
• [Qs-71] Old Benoni: 1.d4 c5 2.d5 (for 2.e4 see Sicilian, Smith-Morra Gambit) then Old Czech Benoni: 2...e5 (for 2...Nf6 3.c4 - see Modern Benoni) 3.e4 d6 where White avoids the Modern Czech Benoni by avoiding c4 and/or Black avoids it by avoiding ...Nf6
• (Robatsch Defence: 1.d4 g6 all transposes out as follows:
• 2.c4 Bg7 (for 2...Nf6 see 1...Nf6) see Modern, Averbakh after either 3.Nc3 d6 4.e4, 3.e4 d6 4.Nc3 or 3.Nf3 d6 4.Nc3 Nf6 (or 3...Nf6 4.Nc3 d6); see 1...Nf6 after either 3.Nc3 Nf6 or 3.Nf3 Nf6, see Modern Benoni after 3.Nc3 c5
• 2.g3 Bg7 3.Bg2 most commonly transposes out to Fianchetto King's Indian; the independent line 3...d6 4.e4 is NSE (there isn't a Fianchetto Modern Defence to transpose to)
• 2.Nf3 Bg7 (for 2...Nf6 see 1...Nf6; for 2...d6 see either Modern Defence 2...g6 after 3.e4, King's Indian Defence after 3.c4 or Fianchetto King's Indian after 3.g3; for 2...f5 see Leningrad Dutch) then 3.c4 (for 3.e4 see Modern Defence, Averbakh after 3...d6 4.Nc3, Modern Benoni after 3...c5 4.d5 or Sicilian Hyper-Accelerated Dragon after 3...c5 4.Nf3; for 3.g3 see Fianchetto King's Indian) 3...d6 (for 3...Nf6 see 1...Nf6; for 3...f5 see Leningrad Dutch) 4.Nc3 Nf6 see King's Indian Defence
• 2.e4 - see Modern Defence)
• (for 1.d4 c6 see Caro-Kann Defence after 2.e4, Slav Defence after 2.c4 d5 or 1...Nf6 after 2.c4 Nf6)
• (for 1.d4 b6 see Owen's Defence after 2.e4)
• (for 1.d4 e5 see Centre Game after 2.e4 (Englund Gambit Accepted is NSE))
• (1.d4 Nc6 Bogoljubow-Miles Defence is NIE due to transposition to Chigorin Defence with 2.c4 d5; [Qs-8] reserved for it)

### Réti Opening: 1.Nf3

White has 80,000 ways of transposing to a 1.d4 opening after 1.Nf3. A point at which White has the additional option of playing d4 is indicated by *.

1.Nf3 d5 * then

1.Nf3 Nf6 * then

• 2.c4 then
• [Fl-21] 2...e6 * 3.Nc3 (for 3.g3 see 2.g3) then Nimzo-English: 3...Bb4 l/o d4 (for 3...d5 4.d4 see 1.d4)
• [Fl-25] 2...g6 * 3.Nc3 (for 3.g3 see 2.g3) 3...d5 * (for 3...Bg7 * see 2.g3 after 4.g3 or King's Indian Defence after 4.e4 d6 5.d4) then Grünfeld Réti: 4.cxd5 Nxd5 - lines where White leaves out d4 (5.e4 Nxc3 is mostly met with dxc3 avoiding the transposition to the Grünfeld)
• (for 2...c5 - see Symmetrical English)
• (for 2...b6 * 3.g3 see 2.g3)
• (for 2...d6 3.d4 - see 1.d4)
• (for 2...c6 * 3.Nc3 d5 * 4.e3 e6 5.d4 see 1.d4 Semi-Slav)
• [Fl-29] Nimzowitsch Attack: 2.b3 g6 3.Bb2 Bg7 4.g3 O-O 5.Bg2 where Black leaves out ...d5 transposing to the Nimzowitsch-Larsen Attack
• (King's Indian Attack Réti: 2.g3 all transposes out as follows:
• 2...b6 3.Bg2 (3.c4 transposes to this after either 3...Bb7 4.Bg2 or 3...e6 4.Bg2; Black can also transpose out to the English with ...c5 at move 3, 4, 5 or 6) 3...Bb7 4.c4 (for 4.O-O see Hedgehog English) 4...e6 * 5.O-O Be7 * 6.Nc3 then for Anglo-Queen's Indian: 6...O-O 7.d4 see 1.d4, Queen's Indian Defence (7.Re1 is NSE)
• for 2...d5 see 1...d5
• 2...g6 * 3.Bg2 (3.c4 Bg7 * 4.Bg2 see 3.Bg2 Anglo-Indian) 3...Bg7 * 4.c4 O-O 5.O-O (or 4.O-O O-O * 5.c4) 5...d6 * 6.Nc3 e5 see Bremen English)

[Fl-31] 1.Nf3 c5 then Barcza System: 2.g3 (for 2.e4 see Sicilian Defence; for 2.c4 see Symmetrical English) 2...Nc6 3.Bg2 l/o c4 or e4

(for 1.Nf3 g6 * 2.c4 Bg7 (for 2...c5 see Symmetrical English; for 2...Nf6 see 1...Nf6) 3.d4 (or 3.Nc3 d6 4.d4) see 1.d4)

(for 1.Nf3 f5 * 2.g3 Nf6 * see Anglo-Dutch after 3.c4 or Leningrad Dutch after 3.Bg2 g6)

(for 1.Nf3 d6 2.d4 see 1.d4)

(for 1.Nf3 e6 * 2.c4 see 1...Nf6 after 2...Nf6 or 1...d5 after 1...d5)

### English Opening: 1.c4

White has 80,000 ways of transposing to a 1.d4 opening after 1.c4. A point at which White has the additional option of playing d4 is indicated by *

White also has 12,000 ways of transposing to a 1.Nf3 opening after 1.c4. A point at which White has the additional option of playing Nf3 is indicated by †

[Fl-41] Anglo-Indian: 1.c4 Nf6 *† 2.Nc3 (for 2.g3 see 1...e5 after 2...e5 or 1...c5 after 2...g6 *† 3.Bg2 Bg7 *† 4.Nc3 O-O *† 5.e4 d6 6.Nge2 c5; 2...e6 *† 3.Bg2 d5 *† is NIE) 2...e6 *† (for 2...g6 *† see 2.g3 after 3.g3 or 1.d4 after 3.e4 d6 4.d4; for 2...e5 see 1...e5; for 2...c5 see 1...c5; Grünfeld English 2...d5 3.cxd5 Nxd5 4.g3 is NIE due to transpositions to the Reversed Sicilian with ...e5 or the Neo-Grünfeld with d4) then Mikenas Attack: 3.e4 l/o d4

[Fl-45] Anglo-Slav: 1.c4 c6 * 2.Nf3 (for 2.e4 see Caro-Kann, English Variation) 2...d5 * 3.e3 Nf6 4.Nc3 l/o d4 for which see Semi-Slav

[Fl-49] Anglo-Dutch: 1.c4 f5 - lines where White avoids transposing to a regular Dutch with d4

(1.c4 b6 is NIE due to transpositions to the English Defence with d4)

Reversed Sicilian 1.c4 e5 2.Nc3 (2.g3 transposes to this after 2...Nf6 3.Bg2 d5 4.cxd5 Nxd5 5.Nc3, 2...Nf6 3.Nc3, 2...Nc6 3.Nc3, 2...Nc6 3.Bg2 Nf6 4.Nc3, 2...Nc6 3.Bg2 g6 4.Nc3 or 2...d6 3.Nc3), then

(for Anglo-French Defence: 1.c4 e6 *† see 1...Nf6 after 2.Nc3 Nf6, 2.g3 Nf6, 2.g3 d5 3.Nf3 Nf6 or 2.g3 d5 3.Bg2 Nf6 or see QGD after 2.Nc3 d5 3.d4)

• [Fl-61] Ultra-Symmetrical English: 2.g3 g6 3.Bg2 Bg7 4.Nc3 Nc6 5.Nf3
• (for 2.Nc3 see Ultra-Symmetrical English after 2...g6 or 2...Nc6 3.g3 g6, or see 2.Nf3 after 2...Nc6 3.Nf3 or 2...Nf6 3.Nf3)
• 2.Nf3 Nf6 (for 2...Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 e6 see 2...Nf6, Symmetrical Two Knights; for 2...Nc6 3.Nc3 g6, 2...g6 3.g3 or 2...g6 3.Nc3 see Ultra-Symmetrical English; for 2...g6 3.d4 Bg7 4.e4 cxd4 5.Nxd4 Nc6, 2...g6 3.d4 cxd4 4.Nxd4 Bg7 5.e4 Nc6 or 2...Nc6 3.d4 cxd4 4.Nxd4 g6 5.e4 see Sicilian Maroczy Bind) then
• [Fl-63] 3.Nc3 then Modern Variation: 3...d5 (for 3...e6 see Hedgehog Defence after 4.g3 b6, Anti-Benoni after 4.d4 or QGD Semi-Tarrasch after 4.e3 d5 5.d4; for 3...Nc6 see 2...Nc6) 4.cxd5 Nxd5 bifurcates into 5.g3 and 5.d4 l/o e4 compared to Exchange Grünfeld
• 3.d4, then
• 3...cxd4 4.Nxd4, then
• [Fl-64] Anti-Benoni: 4...e5
• (4...Nc6 5.Nc3 is NIE due to transposing to Symmetrical Two Knights with 5...e6 and Sicilian Maroczy Bind with 5...g6 6.e4)
• (4...Nc6 5.g3 is NIE due to transpositions to Anglo-Catalan)
• (4...e6 5.g3 see Anglo-Catalan)
• (4...e6 5.Nc3 l/o g3 see Symmetrical Two Knights)
• 3...e6, then
• [Fl-65] Anglo-Catalan: 4.g3 cxd4 5.Nxd4 (or 3...cxd4 4.Nxd4 e6 5.g3) after which 5...d5 is the most common move, with the resulting positions classified as Symmetrical English, Catalan Variation rather than Catalan, ...c5 Variation
• [Fl-66] Symmetrical Two Knights: 4.Nc3 cxd4 5.Nxd4 where White avoids g3 transposing to the Anglo-Catalan and Black avoids the combination of ...Be7 and ...d5 transposing to the QGD Tarrasch
• (for 4.e3 d5 see QGD Tarrasch)
• (for 4.d5 see Modern Benoni)
• (for 3...g6 see 2.Nf3 g6)
• 3.g3 b6 4.Bg2 Bb7 5.O-O then [Fl-67] Hedgehog Defence: 5...e6 6.Nc3 Be7 7.d4 cxd4 8.Qxd4, [Fl-69] Double Fianchetto Defence: 5...g6

(Great Snake: 1.c4 g6 *† transposes out as follows:

• 2.g3 Bg7 (for 2...Nf6 see Anglo-Indian) 3.Bg2 (for 3.Nc3 see 2.Nc3) 3...Nf6 *† (for 3...c5 see 1...c5) 4.Nc3 - see 3.Nc3
• 2.Nc3 Bg7 * (for 2...Nf6 see Anglo-Indian; for 2...c5 see 1...c5) 3.g3 see 2...Nf6 after 3...Nf6 or see 1...e5 after 3...e5
• 2.e4 Bg7 3.d4 - see 1.d4)

### Benko Opening: 1.g3

NIE due to transpositions to Réti King's Indian Attack after 1...e5 2.Bg2 d5 and 1...Nf6 2.Bg2, English after 1...e5 2.c4 and 1...g6 2.Bg2 Bg7 3.c4, and 1.Nf3 after 1...d5 2.Nf3 and 1...d5 2.Bg2 Nf6 3.Nf3. Use Fl-3

### Dunst Opening: 1.Nc3

NIE due to transpositions to almost every other opening. Independent lines 1...d5 2.e4 d4 and 1...d5 2.e4 dxe4 are NSE. Use Fl-91

## Very abridged list (100,000 games per 50,000 1.e4 games)

 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
White to move. This position occurs in 100% of top games and over 99% of amateur games.