Square of the pawn — what it means in chess
The visual rule for whether a lone king can catch a passed pawn.
The visual rule for whether a lone king can catch a passed pawn.
[[board startfen="8/8/8/8/1P3k2/8/8/7K b - - 0 1" pgn="Ke5 b5 Kd6 b6 Kc6 b7 Kxb7" caption="The king stands inside the square of the b4 pawn. It steps in, cuts the diagonal, and arrives exactly in time — the capture on b7 ends the race." notes="Draw the square: from the pawn on b4 to its promotion square b8, then sideways — corners b4, b8, f8, f4. The black king on f4 stands inside it. Inside means the race is already won. The king takes the diagonal, the shortest path in king geometry. The pawn runs. The king keeps pace — note it does not chase the pawn from behind but cuts toward the promotion corner. The pawn runs on. The king reaches c6, now attacking the pawn's next stop. The pawn has no choice. Caught, one square from glory. A king inside the square catches the pawn every time; the diagram made the ten-move calculation unnecessary."]]
[[board startfen="8/8/8/8/1P5k/8/8/7K b - - 0 1" pgn="Kg5 b5 Kf6 b6 Ke7 b7 Kd7 b8=Q" caption="Shift the same king one file outside the square, and the identical chase falls one tempo short: the pawn promotes, and the new queen stands beyond the king's reach." notes="Same pawn, same race — but the king begins on h4, one file outside the b4-f4 square. Outside means the race is already lost, and the moves that follow only make it official. The king sprints on the same diagonal as before. The pawn runs. The king is quick — — but the pawn does not tire. The king strains toward the corner. One more push. The king arrives at d7, a single square too far away to touch b8. Promotion. The queen is out of reach, and the game is over. One file was the whole difference."]]
The Endgame Society glossary defines more than 240 chess terms — rules, notation, tactics, strategy, pawn structures, endgames, and openings — in language a beginner can act on rather than dictionary shorthand.