Place eight queens so that none attacks another.
0 of 8 placed, 0 under attack, 0 s
Eight Queens
The eight queens puzzle asks you to place eight queens on a chess board so that no queen attacks another: no two on the same rank, file or diagonal. Tap a square to place or remove a queen. Queens that attack each other are marked. The puzzle has 92 solutions, and your time is kept.
How to play
- Tap an empty square to place a queen and tap a queen to take it off.
- A queen that shares a rank, file or diagonal with another is marked in red.
- The clock starts with your first queen and stops when eight queens stand with no attacks.
Questions
- How many solutions does the eight queens puzzle have?
- There are 92 ways to place the queens. Many are turns and mirror images of each other: counted without those there are 12 different solutions.
- Is there a trick to it?
- Each rank and each file must hold exactly one queen. Start in a corner area, place queens a knight's move apart, and fix clashes one at a time.
- Who invented the puzzle?
- It was published by the chess composer Max Bezzel in 1848 and has been a standard problem in mathematics and computer science ever since.