What is the largest total number of black and white queens you can place on a standard 8x8 chessboard so that each queen attacks exactly 1 opponent queen?
Click a square to cycle empty -> white -> black -> empty. Place 16 white and 16 black queens so each attacks exactly 1 opponent pieces.
Sign in or create an account to reveal answers, view the solution, and save your progress. Create a free account to unlock practice and keep track of your work.
One puzzle per day. Cryptarithm, Magic Square, Summit. No sign-up required to play.
Play daily puzzle →Interactive problems and curated lessons—water pouring, magic squares, knight's tour, and more.
Browse library →See how you rank. Top solvers by problems solved correctly. Sign in to climb the ranks.
View leaderboard →