Use two heavy pieces like a sliding wall to squeeze the enemy king rank by rank until checkmate.
Follow the lesson one board at a time. The teacher answer key includes the move list.
Solve each position on paper first. Answers live only in the separate teacher/parent key.
White to move. Find checkmate in one.
Start the ladder. Move one rook to make a wall that keeps the king from coming down the board.
The king is boxed in near the back rank. Slide the other rook so the box gets even smaller.
Finish the ladder technique from here. Find White’s forcing sequence all the way to mate.
Play this with a partner. White should keep shrinking the king’s box with the rooks; Black tries to notice when one rook must stay as the wall while the other rook moves.
Teacher/parent key for Worksheet: Ladder Mate.
Prompt: Draw a “wall” on a board diagram and explain how a rook can stop a king from crossing it.
A rook controls every square along its rank and file, so it can draw a wall the king may not cross.
Prompt: In the mini-game, which rook is the wall and which rook is the moving rook right now?
Answers vary by the position reached, but one rook must keep the king boxed while the other rook slides closer.
Prompt: Solve each ladder-mate practice position and write which rank or file became smaller after White’s move.
Practice 1: rank 6 becomes the wall. Practice 2: the box narrows again. Practice 3: Rb7 then Ra8 finishes the mate.
White to move. Find checkmate in one.
Solution: Rg8#
The rook on a7 already covers the whole 7th rank, so the king cannot step forward. Rg8 delivers check along the 8th rank, and with rank 7 blocked, the king has nowhere left to go.
Start the ladder. Move one rook to make a wall that keeps the king from coming down the board.
Solution: Rg6
Rg6 builds a horizontal wall on rank 6. The black king is still safe for the moment, but it has less and less room each turn.
The king is boxed in near the back rank. Slide the other rook so the box gets even smaller.
Solution: Rb6
The rook from a6/b6 takes over the next wall so the rook on g6 can stay ready for the finishing ladder steps.
Finish the ladder technique from here. Find White’s forcing sequence all the way to mate.
Solution: Rb7 Kh8 Ra8#
Rb7 leaves the king only one square. After Kh8, Ra8 is the final rung of the ladder and checkmates.