Chess Puzzles Presented with Solutions in Guardian Column
The Story
The Guardian’s puzzle column, which has run on alternate Mondays since 2015, presented four chess puzzles along with their solutions. The first puzzle asks participants to prove that in a chess tournament where players played an odd number of games, the number of such players must be even. The solution explains that the total number of games played must be even because each game involves two players, and an even sum requires an even count of odd numbers. The second puzzle asks if a knight can start in the bottom right corner of an 8×8 board, visit every square exactly once, and end in the top left corner; the answer is no because a knight alternates square colors with each move and opposite corners share the same color, making the required 63‑move path impossible. The third puzzle asks for the fewest moves needed for a pawn to leave its initial square, be promoted to queen, and return to its starting position with both players collaborating. The solution is six moves, and a sequence is provided involving pawn captures and a knight moving out of the way. The fourth puzzle involves swapping white and black knights on a strangely‑shaped grid, with a solution described as a train‑shunting problem using numbered positions. The puzzles were provided by We Solve Problems, a charity that runs free maths circles for secondary school pupils across the UK.
Key Facts
- The puzzles and solutions were published in a Guardian column that has run since 2015.
- Puzzle 1: Prove that the number of players who played an odd number of games must be even. Solution: The total number of games is even because each game has two players; adding odd numbers to reach an even total requires an even count of odd numbers.
- Puzzle 2: On a regular 8×8 board, can a knight start in the bottom right corner, visit every square exactly once, and end in the top left corner? Solution: No, because opposite corners are the same color, and 63 moves would alternate colors, so start and end colors would differ.
- Puzzle 3: Fewest moves for a pawn to leave its initial square, get promoted, and return to its original position with both players collaborating. Solution: 6 moves; a sequence starting with white pawn B2‑B4, black pawn A7‑A5, then captures, knight move, and pawn advancing and returning.
- Puzzle 4: Swap two white knights and two black knights on a strangely‑shaped grid. Solution: A train‑shunting problem using numbered positions from 1 to 9; sequence of moves to exchange positions.
- The puzzles were supplied by We Solve Problems, a charity that runs free maths circles for secondary school pupils (years 7 to 11) in more than a dozen UK cities between September and May.
- A YouTube clip discusses the final problem.
Conflicting Reports
No conflicting reports identified in the source article.
Still Unclear
No open questions identified in the source article.
Misconceptions
No widespread misconceptions addressed in the source article.
Key Figures
- We Solve Problems (charity listed as source of puzzles)
- No specific individuals named in the source article.
Sources: The Guardian
