# Saturday Puzzle #26 – The Eight Queens Problem

You don’t have to be a chess player, or even know the rules of chess, to have a good time with today’s puzzle. All you need to know is that the queen is the most powerful chess piece – she can move as far as she likes in any direction: forward and back, sideways to the right or left, and diagonally. The diagram on the right illustrates the queen’s awesome power.

Today’s challenge is to place eight queens on a chess board such all 64 squares are attacked and no two queens are attacking each other. To make this puzzle easy and fun, I’ve created a custom software simulation, which you can use to try to solve it yourself right here on my blog (so you don’t even need a chess set). Just click on a square below to add a queen, and keep going until you’ve placed eight queens or run out of space with fewer than eight. You can click on an existing queen to undo a placement and there’s a reset button below the board in case you want to start over. You can also click the “solve” button to have your computer quickly find a random solution (there are many). Have fun and leave me a comment if you manage to solve this one!

 Queens placed: 0 Covered (occupied + attacked) squares: 0
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### 5 Responses to Saturday Puzzle #26 – The Eight Queens Problem

1. Katy says:

Got it! Not sure if I really figured anything out, just saw some likelihoods and kept trying until it worked. Thanks for the new game!

2. Simon Banks says:

Very good Marc. I’ve two solutions for this problem.. Shame my iPad or the webapp doesn’t have a screenshot feature.

3. Simon Banks says:

Interesting it turns out you can do screen grabs on an iPad, press the home and off button together. Fancy that ;-)

4. Neal says:

Got it–but it was only partly by design.

5. Jay says:

A reverse challenge might be, how few queens can you use to attack all the unoccupied squares? I got it down to five.