Guardian publishes solutions to four quirky chess puzzles
7 reported
The Guardian published solutions to four chess puzzles it had set earlier in the day. The puzzles included proving that the number of players who played an odd number of games in a tournament must be even, determining whether a knight can visit every square on a board and end on the opposite corner, finding the fewest moves for a pawn to leave, promote, and return to its starting square, and swapping the positions of two pairs of knights on a strangely-shaped grid. The solutions were provided in the article, with the final problem discussed in a linked YouTube clip. The puzzles were contributed by the charity We Solve Problems, which runs free maths circles for secondary school pupils in the UK. The article noted that the puzzle series has been running on alternate Mondays since 2015.
What’s reported
The article presents solutions to four chess puzzles.
Puzzle 1 solution: The total number of games played must be even, so the number of players with an odd number of games must be even.
Puzzle 2 solution: A knight cannot start on one corner and end on the opposite corner because opposite corners are the same color.
Puzzle 3 solution: The fewest number of moves for a pawn to leave, promote, and return to its original position is 6.
Puzzle 4 solution: The knights can be swapped by treating the board as a train shunting problem.
The puzzles were provided by the charity We Solve Problems.
The charity runs free maths circles for secondary school pupils (years 7 to 11) in more than a dozen UK cities.
Key figures
We Solve Problems (charity)
Sources: The Guardian
