The rule of the square
Step 1 of 7
The pawn is on b4, four squares from becoming a queen. Draw a side from the pawn to b8, and a side of the same length across: you get a square with the corners b4, b8, f8 and f4. If the black king is inside this square, or can step into it on its move, it catches the pawn.
Watch: each time the pawn moves, the square gets smaller, but the king stays inside it and catches the pawn in the end.
Move 0 of 8
Black to move. Can the black king catch the pawn on a4? Draw the square in your head.
Task in progress
Black to move. Can the black king catch the pawn on b4?
Task in progress
Black to move. Can the black king catch the pawn on c5?
Task in progress
Draw the square of the pawn on c4 in your head. One corner is c8, where the pawn becomes a queen. Which is the other corner on the 8th rank? Tap it.
Task in progress
The black king is outside the square. Push your pawn at once and make it a queen.
Task in progressMoves: 0 of 5