In chess, tempo refers to a "turn" or single move. When a player achieves a desired result in one fewer move, the player "gains a tempo"; and conversely when a player takes one more move than necessary, the player "loses a tempo". Similarly, when a player forces their opponent to make moves not according to their initial plan, one "gains tempo" because the opponent wastes moves. A move that gains a tempo is often called a move "with tempo".
A simple example of losing a tempo may be moving a rook from the h1-square to h5 and from there to h8 in the first diagram; simply moving from h1 to h8 would have achieved the same result with a tempo to spare. Such maneuvers do not always lose a tempo however—the rook on h5 may make some threat which needs to be responded to. In this case, since both players have "lost" a tempo, the net result in terms of time is nil, but the change brought about in the position may favor one player more than the other.
|This article uses algebraic notation to describe chess moves.|
Gaining a tempo
Gaining tempo may be achieved, for example, by developing a piece while delivering check, though here, too, if the check can be countered by the development of a piece, the net result may be nil. If the check can be blocked by a useful pawn move which also drives the checking piece away, the check may even lose a tempo.
In general, making moves with gain of tempo is desirable. A player is said to have the initiative if they are able to keep making moves which force their opponent to respond in a particular way or limit their responses. The player with the initiative has greater choice of moves and can to some extent control the direction the game takes, though this advantage is only relative, and may not be worth very much (having a slight initiative when a rook down, for example, may be worthless).
In the Scandinavian Defense, after 1.e4 d5 2.exd5 Qxd5, if White plays 3.Nc3 the knight attacks Black's queen, forcing it to move again, and White gains a tempo. A similar move gains a tempo in the Center Game opening.
Losing a tempo
In some endgame situations, a player must actually lose a tempo to make progress. For example, when the two kings stand in opposition (a form of zugzwang), the player to move is often at a disadvantage because he must move. The player to move may be able to triangulate in order to lose a tempo and return to the same position but with the opponent to move (and put him in zugzwang). Kings, queens, bishops, and rooks can lose a tempo; a knight cannot (Müller & Pajeken 2008:40,175,189).
In the position from a 2008 game between Artyom Timofeev and Ernesto Inarkiev, Black resigned because White will win with a tempo move. (Timofeev won the 2008 Moscow Open with this game.) White is threatening 118.Rh8+. If Black moves his king on move 117, White wins the bishop with 118.Rh8+, which results in a position which has an elementary checkmate. If Black moves 117...Bh5 then 118.Rh8 and Black is in zugzwang, and loses. So Black must move 117...Be2 to avoid immediately getting into a lost position. But then will come 118.Rh8+ Bh5 and now White makes a tempo move with 119.Rh7 (or 119.Rh6), maintaining the pin on the bishop, making it Black's turn to move, and Black must lose the bishop.
A spare tempo in an endgame arises when a player has a pawn move that does not essentially change the position but that loses a tempo to put the opponent in zugzwang. In this example, if only the queenside pieces were considered, it would be an instance of reciprocal zugzwang – the player to move would lose. In the full position, White has two spare tempos (f2–f3 and h2–h3) whereas Black has only one (f7–f6), so White has a spare tempo. By using these moves he can force Black into a fatal zugzwang:
- 1. h3 f6
- 2. f3
and any move Black makes will lose.
If the black pawn had been on h7 instead of h6, White and Black would have an equal number of spare tempos, so the player to move would lose (Burgess 2009:533).
A pawn may have a reserve tempo, mainly in endgames involving only kings and pawns. This is especially true of a pawn on the second rank, where it has the option of moving one or two squares. Pawn moves held in reserve may be used to win a game.
- 39... Kc6
- 40. Kd4 a5
- 41. a4
- 40. Kd4 Kc6
- 41. a3 a5
- 42. a4 (Hooper & Whyld 1992:416).
In both cases, Black must now abandon his pawn on d5 (or first move and lose his pawn on f7). White is able to place Black in zugzwang because he has the option of moving the pawn on a2 either one square or two squares.
- Burgess, Graham (2009), The Mammoth Book of Chess (3rd ed.), Running Press Book Publishers, ISBN 978-0-7624-3726-9
- Euwe, Max; Hooper, David (1959), A Guide to Chess Endings, Dover (1976 reprint), ISBN 0-486-23332-4
- Hooper, David; Whyld, Kenneth (1992), "Tempo", The Oxford Companion to Chess (2nd ed.), Oxford; New York: Oxford University Press, ISBN 978-0-19-866164-1
- Müller, Karsten; Pajeken, Wolfgang (2008), How to Play Chess Endings, London: Gambit Publications, ISBN 978-1-904600-86-2, OCLC 212407634, transl. from German by Phil Adams.