Opposition
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.
Common mistake: heading for the standoff without counting who will be on move when the kings meet, since one spare pawn move can hand the move to the other side.
Kings may never stand on neighboring squares, so when they meet head on with one square between them, that middle square belongs to nobody. The king that has to move next cannot go forward and must step aside or back, and the other king then advances into the space it gave up.
In pawn endings that single step is often the whole game. The attacking king wants to reach a key square in front of its pawn, and the defending king wants to stand in its way. Whoever holds the standoff at the right moment wins that argument, as in the diagram, where taking it is the only winning move.
Two habits help. First, look at the square you want your king to reach and ask which king will be on move when the two meet in front of it. Second, remember that a pawn move changes who is on move, so count the spare pawn moves on both sides before relying on the standoff.
The same idea works at longer range along a file and along diagonals, and it grows into the wider method of corresponding squares. Holding the standoff only pays when something lies beyond the enemy king, such as a key square or a pawn to win; with no target behind it, the standoff achieves nothing.
It sits close to Diagonal opposition. Diagonal opposition is the standoff in which the two kings sit on the same diagonal with exactly one empty square between them, so the king that has to move must give ground.
It sits close to Distant opposition. Distant opposition is the long-range form of the kings' standoff: the kings share a line with an odd number of empty squares between them, and the side not on move can keep that count odd until the kings meet.
It sits close to King and pawn endgame. 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.
If "Opposition" 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
Distant opposition is the long-range form of the kings' standoff: the kings share a line with an odd number of empty squares between them, and the side not on move can keep that count odd until the kings meet.
Diagonal opposition is the standoff in which the two kings sit on the same diagonal with exactly one empty square between them, so the king that has to move must give ground.
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.
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.
Key squares are the target squares for the attacking king in a pawn ending: once it reaches one while its pawn is safe, the pawn promotes by force, no matter whose move it is.
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.
How much does chess coaching cost?
Published rates for private, group and subscription chess coaching, with the source and the date of each.
A game review, a read on your level and a written study plan from George Li.
Want to spot this in your own games?
A first lesson starts with your games: George reviews them and builds a study plan around what he finds.