Escaping the checks
1.c7 is the only winning move; every king move only draws. Black's rook cannot stop the pawn directly, so it checks: 1...Rd6+ 2.Kb5 Rd5+ 3.Kb4 Rd4+ 4.Kb3 Rd3+ 5.Kc2. The king walks down the board towards the rook until the checks run out.
On the second move only 2.Kb5 wins. 2.Kc5 lets the rook drop to the first rank and check from behind on the c-file, and the game is drawn. The position is named after Fernando Saavedra, who found the winning idea in 1895.
The stalemate trap
With no checks left, Black plays 5...Rd4. If 6.c8=Q, then 6...Rc4+ 7.Qxc4 is stalemate: the black king on a1 has no legal move. Any king move instead lets the rook take the queen on c8.
The rook promotion
6.c8=R avoids the stalemate and threatens Ra8+, which leads to mate on the a-file. Black stops that with 6...Ra4, and then 7.Kb3 attacks the rook and threatens Rc1 mate at the same time. Black cannot meet both threats.
Promoting to a queen draws, and a bishop or a knight even loses. Before promoting, always ask what the opponent can do against each choice.
Remember
- Push the pawn at once
- Walk the king towards the rook
- Spot the stalemate trap
- Promote to a rook