Eight Queens

A problem from 1848 that still catches people out. A queen covers her whole rank, her whole file and both diagonals, so eight of them on one board leaves almost nowhere legal — and the first six are easy in a way that makes the last two feel impossible.

The board shows how many queens are placed, how many are under attack and how many are still to come, and it will draw the attack paths if you want to see why a square is refused.