Reserve tempo
A reserve tempo is a spare, harmless move, usually a pawn move, that one side can make without damaging its position, passing the obligation to move across to the opponent.
Also called: spare tempo
In many endgames the winner is the player who runs out of useful moves last. A reserve tempo is a move you can afford to burn: a pawn push that weakens nothing, or a rook shuffle that still covers every key square. The idea matters most when the kings are locked in a standoff, such as the opposition, where whoever moves first must give way. If you hold such a move and your opponent has none, the opponent must give way with the king and yours walks in.
Count tempi before committing your king. Ask how many harmless pawn moves each side has, whether a pawn is still on its starting rank and so owns two single steps or a double step, and whether any push would open a new square to the enemy king. A pawn that has already moved once has one fewer spare move than it did before.
A typical error is to spend a spare move early, because it looks natural, and then lack it when the kings finally face each other. Another is to forget that the opponent may be counting too, so a plan that works against a bare king fails in the real position. Keep your spare moves in your pocket until the position actually demands them.
A neighboring idea is Tempo. A tempo is a single move counted as a measure of time: gaining one means making a useful move that also forces the opponent to react, while losing one means spending a move that accomplishes nothing.
It sits close to Trebuchet. The trebuchet is a mutual zugzwang in which two kings stand on either side of a pair of locked pawns, each beside the enemy pawn, so whoever must move loses a pawn and the game.
A neighboring idea is Triangulation. Triangulation is a way for a king to hand the move to the opponent: it makes a three-move loop over neighboring squares and returns to its starting square, while the enemy king, with less room, cannot copy the loop.
If "Reserve tempo" has cost you half a point, a first lesson is a good place to find the pattern behind it: George Li goes through your games and builds a plan.
Related terms
Opposition is a standoff between the two kings on one file or rank with a single empty square between them; whoever does not have to move holds it, because the other king must give up ground.
Zugzwang is the bind of having to move when standing still would be best: the player on move has only moves that weaken the position, and since passing is not allowed, the duty to move itself costs something.
A mutual zugzwang is a position in which whichever player has to move is worse off, so each side would gladly pass, and the result depends entirely on whose turn it is.
A waiting move keeps your position exactly as strong as before and simply hands the opponent the obligation to move, which helps whenever every reply they have makes their position worse.
Triangulation is a way for a king to hand the move to the opponent: it makes a three-move loop over neighboring squares and returns to its starting square, while the enemy king, with less room, cannot copy the loop.
A king and pawn endgame is an ending in which only kings and pawns remain, so the result depends on promotion races, king placement, opposition, and exact counting of moves.
Guides that go further
What to decide first, the questions to ask, what a first lesson should show and the red flags to avoid.
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A game review, a read on your level and a written study plan from George Li.
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