Endgame trainer
Take the opposition
Two kings, one idea that decides countless endings. Drag either king and watch who holds the opposition — direct, distant or diagonal — flip live as they face off.
Drag either king. The opposition updates as they move.
Black has the direct opposition.
The side to move must give way — the other king can then advance.
Side to move
The opposition: when the kings face off on the same file, rank or diagonal with an odd number of squares between them, whoever is not to move holds it. The one who must move has to step aside, letting the other king make progress. Winning most king-and-pawn endings comes down to taking the opposition at the right moment.
Next: will the pawn queen? (rule of the square) or the endgame trainer.