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Ashta’s chess tales

Ninety-two ways

Germany, 1848 · 2 minute read

A question in a chess magazine that mathematicians could not leave alone.

In 1848 a chess player named Max Bezzel sent a puzzle to a magazine. It was one sentence long. Can you place eight queens on a chessboard so that no queen attacks another?

A queen attacks along her row, along her column, and along both diagonals. Eight queens need eight different rows and eight different columns — and somehow no two may share a diagonal either. It sounds as though it ought to be impossible.

It is not. Two years later another man, Franz Nauck, published the answers. There are exactly ninety-two.

The puzzle caught the eye of Carl Friedrich Gauss, one of the greatest mathematicians who ever lived. He worked on it in letters to a friend.

And here is the neat part. Many of the ninety-two are really the same answer seen differently — turn the board a quarter turn, or look at it in a mirror, and one answer becomes another. Take away those copies and only twelve truly different answers are left.

Much later, when computers were invented, this little puzzle became one of the first problems that students of programming were asked to solve. It still is.