八皇后
- 尝试、规律与证明
- Ages 9 and up
- About 8 minutes
The story behind it
In 1848 a chess player named Max Bezzel asked a question in a magazine: can eight queens stand on a chessboard so that none attacks another? Mathematicians could not leave it alone. There turned out to be exactly 92 ways.
Read the full story: Ninety-two ways →How to play
- Tap a square to place a queen. Tap her again to lift her.
- Shaded squares are already attacked.
- Start small: four queens on a four-by-four board.
Levels
For teachers and coaches
Eight queens — Trial, pattern and proof
Ages 9 and up · about 8 minutes · 8by8verse Chess Lab
What it teaches
Working systematically, spotting symmetry, and reasoning about what is impossible.
The story to tell first
In 1848 a chess player named Max Bezzel asked a question in a magazine: can eight queens stand on a chessboard so that none attacks another? Mathematicians could not leave it alone. There turned out to be exactly 92 ways.
Three questions to ask
- Why can no two queens share a row? What does that tell you about where to start?
- Turn your answer a quarter turn. Is it a new answer or the same one?
- Why is there no answer at all on a three-by-three board?
Without a screen
Use eight counters on a paper board. Pairs race to find one answer, then compare — are any two the same answer turned around?
Next
Finish
Hint
Step back
Start again
Play again
Next level
Back to the lab
Right.
Not quite.
Not yet — have another go.
Question {n} of {total}
{right} out of {total} right.
Three stars. Clean work.
Two stars. Well played.
One star. Level done.
king
queen
rook
bishop
knight
pawn
Place {n} queens so that none attacks another. {k} placed.
Two queens can see each other.
Only {n} queens. Tap a queen to lift her.
{n} queens, and not one attacks another.
Place five queens so that every square is guarded. {k} squares still unguarded.
Five queens guard all 64 squares.