The pawn touches the last rank and the queening instinct takes over. You push it across, reach for the biggest piece on the tray, and never look again. Most of the time that is exactly right. The Saavedra position exists to prove the exception — and to teach a lesson that can save you half a point in real games.
It is one of the most famous endgame studies in chess, and the chess writer A. J. Roycroft called it "unquestionably the most famous of all endgame studies." It is also a puzzle about a queen you should refuse.
Set the board. White: king on b6, pawn on c6. Black: king on a1, rook on d5. White to move and win.
The forcing part is easy to find. White pushes 1. c7, and Black checks along the file: 1...Rd6+ 2.Kb5 Rd5+ 3.Kb4 Rd4+ 4.Kb3 Rd3+ 5.Kc2. The checks are running out, and Black has just one last trick: 5...Rd4!, placing the rook where it can meet the promotion. If White now blithely plays 6.c8=Q, Black answers 6...Rc4+! and White must capture — 7.Qxc4 is stalemate. Black escapes with a draw from a lost position.
White's winning move is the quiet thunderbolt 6.c8=R!!, an underpromotion to a rook. Black's stalemate trap no longer works: a rook on c4 fails to cover a2, so Black is never stuck. Black's best try is 6...Ra4, but 7.Kb3 attacks the rook and threatens 8.Rc1#. Black loses the rook or gets mated. The one spare file of the queen's power — those extra diagonal squares she covers that a rook cannot — is exactly what nearly turned a win into a draw.
Underpromotion is rare in tournament chess, for a good reason. A queen is usually the best piece. But there are two cases where a lesser piece wins: a knight arriving with check or fork, and a rook (or bishop) that avoids the stalemate a new queen would cause. The Saavedra position is the textbook picture of the second.
Its story is as good as its finish. Its roots lie in a game between Richard Fenton and William Potter in 1875, which ended in a draw even though Potter's side had a win. After Potter died in March 1895, Georges Barbier — a Frenchman who had been Scottish champion in 1886 — published the position in his Glasgow Weekly Citizen column on 27 April 1895, misremembering the old game. Barbier thought Black could hold the draw by stalemate and printed that solution on 11 May.
Then Fernando Saavedra, a Spanish priest living in Glasgow and a member of the city's chess club — by all accounts a very modest player — looked at it and spotted what everyone else had missed. c8=R wins; the rook neatly side-steps the stalemate. Barbier published Saavedra's correction in his column on 18 May, and a single move made a name immortal. The version we study today, with White to move and win, was later fixed up by Emanuel Lasker, who published it in the Brooklyn Daily Eagle in June 1902.
Every endgame book since has carried it, and the moral bears repeating: do not promote in a hurry. Before you grab the queen, check whether her extra mobility has left the enemy king with no legal moves. If it has, sometimes the humbler rook, doing the same job with fewer squares, is the piece that wins.