Minesweeper: Murky Origins, One Famous Window
No known inventor; TechRadar, Eurogamer and the game's own author disagree. Then 1990, Windows, world records — and a genuine NP-complete theorem. Read more
Archive: 2026
Nim: The Pile Game With a 1901 Theorem Inside
Nobody can date Nim's origin — but its winning strategy has a birthday: 1901, Charles Bouton, Harvard. Our computer opponent runs that theorem every turn. Read more
Kakuro: Rules, Strategy and Controls — a Player's Manual
Kakuro rules and controls: fill a digit crossword so every run adds to its clue with no repeats — arithmetic deduction, newspaper heritage. Read more
Nurikabe: Rules, Strategy and Controls — a Player's Manual
Nurikabe rules and controls: shade the sea, size every island to its number, keep the water in one piece and never let it pool in a 2×2 square. Read more
Slitherlink: Rules, Strategy and Controls — a Player's Manual
Slitherlink rules and controls: one closed loop along a dot grid, where every number 0-3 counts how many of its box's four edges the loop uses. Read more
The knight that crossed the whole board
A thousand years of the knight's tour: Sanskrit verse, Euler, the 1823 rule of Warnsdorff — and the tool that still uses it to photograph our own game. Read more
Why Our Puzzles Have a Single Solution
The WPC rulebook demands exactly one solution per puzzle. We opened our own generator code and asked every engine what it actually guarantees. Read more
299 ways to reason: a map of the World Puzzle Championship
The World Puzzle Championship is not one game but a bestiary of pencil-and-paper types. Here is the map by family — and where our 120-game catalog sits on it. Read more
Akari (Light Up): Rules, Strategy and Controls — a Player's Manual
Akari (Light Up) rules and controls: place bulbs so every free cell glows, no bulb shines on another, and each numbered wall gets exactly its count. Read more
Creek: Rules, Strategy and Controls — a Player's Manual
Creek is a shading puzzle where the numbers sit on the crossings, not in the cells — and every free cell must connect. Rules, strategies and controls. Read more
Cryptarithmetic: Rules, Strategy and Controls — a Player's Manual
Cryptarithmetic rules and controls: decode every letter to a unique digit, make the sum add up for real, and get mileage out of your three hints. Read more
Hashiwokakero (Bridges): Rules, Strategy and Controls — a Player's Manual
Hashiwokakero rules and controls: give every island exactly as many bridges as its number, keep the whole network connected, and spend your five hints well. Read more
Hex: Rules, Strategy and Controls — a Player's Manual
Hex rules, controls and strategy in one page: how the connection game works, how the built-in AI scales with difficulty, and why a draw is impossible. Read more
Knight's Tour: Rules, Strategy and Controls — a Player's Manual
Knight's Tour rules and controls: visit every square exactly once with L-shaped jumps, survive with all 36 numbers placed, and learn Warnsdorff's classic trick. Read more
Masyu: Rules, Strategy and Controls — a Player's Manual
Masyu rules and controls: draw one closed loop through every pearl — black pearls force the turn, white pearls demand the straight — on grids up to 7×8. Read more
Peg Solitaire: Rules, Strategy and Controls — a Player's Manual
Peg Solitaire rules and controls for the 33-hole English board: how jumps work, why a win needs exactly 31 of them, and the strategies the cross rewards. Read more
Pipe Puzzle: Rules, Strategy and Controls — a Player's Manual
Pipe Puzzle rules and controls: rotate every tile back into one leak-free network, use your three hints well, and pick the board size from 5×5 to 11×11. Read more
Sudoku: Rules, Strategy and Controls — a Player's Manual
The rules of Sudoku step by step, the strategies that actually solve a board and every control — mouse, keyboard and gamepad. Deduction, not luck. Read more
Thermometers: Rules, Strategy and Controls — a Player's Manual
Thermometers: raise the mercury from each bulb, satisfy the row and column counts. Full rules, strategies and controls for this logic puzzle. Read more
The Spanish Deck: Six Centuries of Playing Cards in Four Suits
Coins, cups, swords and clubs: how the Spanish-suited deck kept its medieval pips for over six centuries, and why Klondike still works with it. Read more