In chess, a transposition is a sequence of moves that results in a position that may also be reached by another, more common sequence of moves. Transpositions are particularly common in the opening, where a given position may be reached by different sequences of moves. Players sometimes use transpositions deliberately, to avoid variations they dislike, lure opponents into unfamiliar or uncomfortable territory or simply to worry opponents. To transpose is to play a move that results in a transposition. Transposition tables are an essential part of a computer chess program. Transpositions exist in other abstract strategy games such as shogi, Go, tic-tac-toe and Hex.

Examples

Positions reached by different routes

For instance, the first position can be obtained from the Queen's Gambit: But this position can also be reached from the English Opening: so the English Opening has transposed into the Queen's Gambit. The second position shows another example. The position can arise from the French Defence: The identical position can also be reached, with two extra moves played by each side, from the Petrov Defense: This third position shows another example. This position can be reached from the Exchange variation of the Queen's Gambit Declined: The identical position can also be reached from the Classical variation of the Nimzo-Indian Defence:

<!-- The fourth position shows another example. The position can arise from the Sveshnikov variation of the Sicilian Defence: The identical position can also be reached, with one extra move played by each side, from the Four Knights variation of the Sicilian Defence: The position on the right, featuring a [Maróczy Bind](https://bliptext.com/articles/mar-czy-bind), can be reached from the [Sicilian Defence](https://bliptext.com/articles/sicilian-defence): The identical position can also be reached from the [King's Indian Defence](https://bliptext.com/articles/king-s-indian-defence): The position on the right can be reached from the [Sicilian Defence](https://bliptext.com/articles/sicilian-defence): The identical position can also be reached from the [Pirc Defence](https://bliptext.com/articles/pirc-defence): The position on the right can be reached from the [Giuoco Piano](https://bliptext.com/articles/giuoco-piano): The identical position can also be reached from the [Berlin Defence](https://bliptext.com/articles/berlin-defence-chess): The position on the right, featuring an [isolani](https://bliptext.com/articles/isolani) can be reached by many different openings and move orders. For example, there's the [Nimzo-Indian Defence](https://bliptext.com/articles/nimzo-indian-defence): [Caro–Kann Defence](https://bliptext.com/articles/caro-kann-defence): -->

Transposition possibilities of some openings

Some openings are noted for their wide range of possible transpositions, for example the Catalan Opening and Sicilian Defence. For a simple example, the opening moves 1.d4 e6 (the Horwitz Defence) can transpose very quickly into a wide range of openings, including: