# Chess/Opening theory table

This article uses algebraic notation to describe chess moves.
A chess opening theory table or ECO (Encyclopedia of Chess Openings) table presents lines of moves, typically (but not always) from the starting position. Notated chess moves are presented in the table from left to right. Variations on a given line are given horizontally below the parent line.

## Theory tables on Wikibooks

Theory tables are a way of representing chess variations from a position in a quick reference manner. Chess opening books sometimes make extensive use of them to represent a good amount of information in a compact form. Here on Wikibooks the compactness is not so useful, but the quick reference manner can help the chess player familiar with theory tables quickly locate the information required.

## Arrangement

Chess opening theory tables are commonly published in opening books with annotations by experienced chess players. These tables are typically arranged in a compact manner to allow experienced players to see variations from a position quickly. Usually, the table indicates that either White or Black has equal, slightly better, or better chances at the end of the variation. Sometimes, this information is distilled down to mere symbols or the percentage of games (usually tournament games) where White won – no information is usually given on what the assessment is based on or how to proceed in the game.

## Notation

Typically, each table has a heading indicating the moves required to reach the position for which the table provides an analysis. The first row provides the move numbers with subsequent row representing different variations. White half-moves are shown above black half-moves. Ellipses (...) represent moves that, for the variation, are identical to the variation above. Bold type indicates that another variation is considered elsewhere – usually in another table. A dash (-) indicates that the variation transposes to a variation elsewhere. Transpositions are common in chess – a given position can often be reached by different move orders – even move orders with more or fewer moves.
It is common to add notes regarding whether a certain variation is considered better for White or for Black. This is done at the end (i.e. to the right) of every variation, using shorthand notation regarding specific positions. For instance, the remark += (or +/=) indicates that White has a slight advantage. If reversed (=+ or =/+) this would be true for Black instead.

## Example theory table
### Example 1

1. d4 Nf6 2. c4 e5
| 3 | 4 | 5 | 6 | 7 | 8 |
| d5 Bc5 | Nc3 d6 | = |
| dxe5 Ne4 | Nf3 Nc6 | a3 d6 | exd6 Bxd6 | Nbd2 Bf5 | Nxe4 | += |
| ... Ng4 | Nf3 Bc5 | e3 Nc6 | Be2 O-O | O-O Re8 | Nc3 | += |
| ... ... | Bf4 Nc6 | Nf3 Bb4+ | Nbd2 Qe7 | e3 Ngxe5 | Nxe5 Nxe5 | += |

### Example 2

1.e4 Nf6
| | 2 | 3 | 4 | 5 | 6 |
| Main Line | e5 Nd5 | d4 d6 | Nf3 Bg4 | Be2 e6 | O-O Be7 | ∞/= |
| | Nc3 d5 | exd5 Nxd5 | Bc4 Nb6 | Bb3 Nc6 | Nf3 Bf5 | = |
| | d3 e5 | Nf3 Nc6 | g3 Bc5 | Bg2 O-O | O-O d6 | = |
| | ... ... | f4 Nc6 | Nf3 d5 | fxe5 dxe4 | exf6 exf3 | =/+ |
| Krejcik Variation | Bc4 Nxe4 | Bxf7+ Kxf7 | Qh5+ Kg8 | Qd5+ e6 | Qxe4 d5 | =+ |
| | ... ... | ... ... | ... g6 | Qd5+ e6 | Qxe4 d5 | =+ |
| | ... ... | ... ... | ... ... | ... Ke8 | Qxe4 d5 | =+ |

## Shortcomings

Chess opening theory books that provide these tables are usually quite large and difficult for beginners to use. Because the table entries typically do not include the themes or goals involved in a given line, beginners will either try to memorize the tables (not an easy task) or simply drown in the detail. Chess Opening Theory aims to bridge this gap by providing this type of information at the end of each line.

## External sources of chess theory tables

* Nunn's Chess Openings. 1999. John Nunn (Editor), Graham Burgess, John Emms, Joe Gallagher. ISBN 1-8574-4221-0.
* Modern Chess Openings: MCO-14. 1999. Nick de Firmian, Walter Korn. ISBN 0-8129-3084-3.
* Kasparov, Garry, & Keene, Raymond 1989 Batsford chess openings 2. ISBN 0-8050-3409-9.
* Aleksandar Matanovic, editor, Encyclopaedia of Chess Openings, 5 volumes (Belgrade: Šahovski informator)