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.

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: