A famous chess problem that asks in how many
ways eight queens can be placed on a chessboard so that no two attack each
other. The generalized problem, to find how many ways n queens
can be placed on an n × n board so that no two attack
each other, was first posed by Franz Nauck in 1850. In 1874 GŁnther and
Glaisher described methods for solving this problem based on determinants.
The number of distinct solutions, not counting rotations and reflections,
for board sizes of 1 × 1 to 10 × 10 is 1, 0, 0, 1, 2, 1, 6, 12,
46, and 92, respectively. The 6 × 6 puzzle, for which there is a solitary
unique solution, was sold in Victorian London in the form of a wooden board
with 36 holes into which pins were placed, for one penny.