Transposition (chess)
A transposition in chess is a sequence of moves that results in a position which may also be reached by another, more common sequence of moves. Transpositions are particularly common in opening, where a given position may be reached by different sequences of moves. Players sometimes use transpositions deliberately in order to avoid variations they dislike, lure opponents into unfamiliar or uncomfortable territory or simply to worry opponents.[1][2]
In chess the verb "transpose" means shifting the game on to a different opening track from that on which it started.
Transposition tables are an essential part of a computer chess program.
Examples
Positions reached by different routes
| 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 | ||
For instance, the first position can be obtained from the Queen's Gambit:
- 1. d4 d5
- 2. c4 e6
- 3. Nc3 Nf6
But this position can also be reached from the English Opening:
- 1. c4 Nf6
- 2. Nc3 e6
- 3. d4 d5
so the English Opening has transposed into the Queen's Gambit.
| 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 | ||
The second position shows another example. The position can arise from the French Defence.
- 1. e4 e6
- 2. d4 d5
- 3. exd5 exd5
- 4. Nf3 Nf6
The identical position can also be reached, with two extra moves played by each side, from the Petrov Defense:
- 1. e4 e5
- 2. Nf3 Nf6
- 3. Nxe5 d6
- 4. Nf3 Nxe4
- 5. d3 Nf6
- 6. d4 d5[3]
Transposition possibilities of some openings
Some openings are noted for their wide range of possible transpositions, for example the Catalan Opening and Sicilian Defence.[2][4]
For a simple example, the opening moves 1. d4 e6 can transpose very quickly into a wide range of openings, including:
| 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 | ||
| 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 | ||
| 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 | ||
| 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 | ||
| 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 | ||
| 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 | ||
See also
References
- ^ Mark Weeks. "Chess Opening Tutorial : Introduction to 1.d4". about.com.
- ^ a b Soltis, A. (2007). Transpo Tricks in Chess. Batsford. ISBN 0713490519. See review at "Transpo Tricks in Chess - review". chessville.com.
- ^ Hooper, David; Whyld, Kenneth (1992). The Oxford Companion to Chess. Oxford University Press. ISBN 0-19-866164-9.
- ^ Fine, R. Ideas Behind the Chess Openings. Random House. ISBN 0812917561.
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