Best Logic Puzzle

Tsumego (詰碁) are Go life-and-death puzzles requiring the player to find the sequence that captures or secures a group of stones, practiced as a core training method in East Asian Go tradition for over a thousand years.

The Zebra Puzzle (often attributed to Albert Einstein, though without firm evidence) is a classic five-house logic grid puzzle that popularized the deductive constraint satisfaction genre in the 20th century.

Killer Sudoku is a logic puzzle that combines the standard Sudoku grid with elements of Kakuro arithmetic. The 9x9 grid contains no pre-filled numbers; instead, cells are grouped into cages marked with a target sum. Solvers must deduce the placement of digits from 1 to 9, ensuring that no number rep...

Fillomino is a grid-based logic puzzle published by the Japanese company Nikoli. The objective is to divide the grid into regions known as polyominoes. Each cell within a given region must contain a number equal to the total number of cells in that region. While some numbers are provided as starting...

Picross 3D is a puzzle game developed by HAL Laboratory and published by Nintendo for the Nintendo DS in 2009. It adapts the traditional 2D nonogram logic puzzle format into a 3D space. Players use the stylus to chip away at blocks in a large cube, using numerical clues on the rows and columns to de...

Star Battle is a logic puzzle played on a grid that is divided into outlined, irregularly shaped regions. Solvers must place a specific number of stars into the grid such that every row, column, and outlined region contains the required amount. The primary rule constraint is that stars cannot touch...

Thermo-Sudoku is a variant of the traditional Sudoku puzzle that incorporates a constraint based on thermometer-shaped lines drawn on the grid. Along each thermometer line, digits must strictly increase in value starting from the unnumbered bulb end and moving toward the tip. Standard Sudoku rules s...

Knights and Knaves is a class of logic puzzles set on a fictional island where knights always tell the truth and knaves always lie, formalized by logician Raymond Smullyan in his 1978 book What Is the Name of This Book?

Hashiwokakero, meaning 'build bridges' in Japanese, is a grid-based logic puzzle published by the Japanese puzzle company Nikoli and also known by the English name Bridges. The puzzle consists of a grid containing numbered circles representing islands, where each number indicates the total bridges c...

KenKen is an arithmetic logic puzzle invented in 2004 by Japanese educator Tetsuya Miyamoto, who developed it as a teaching tool for his classroom. The puzzle is played on a square grid in which each row and column must contain the digits 1 through N without repetition, forming a Latin square. The g...

The Seven Bridges of Königsberg is a foundational graph theory problem solved by Leonhard Euler in 1736, whose proof that no Eulerian path exists through the Prussian city's bridges established the field of graph theory.

German Whispers Sudoku is a variant of Sudoku in which a supplementary constraint applies to marked lines within the grid: adjacent digits along each marked line must differ by at least 5. The constraint is named after the party game 'telephone' ('Chinese whispers' or 'German whispers'), reflecting...

Heyawake is a grid-based logic puzzle published by Nikoli, played on a rectangular grid subdivided into rectangular rooms. The solver must shade some cells according to three constraints: numbered rooms contain exactly the indicated number of shaded cells; no two shaded cells may be orthogonally adj...

Arrow Sudoku is a logic puzzle variant that overlays standard Sudoku rules with arithmetic constraints. The grid features arrows originating from empty circles. The digit placed in a circled cell must equal the sum of the digits placed along the corresponding arrow's path. While standard Sudoku rule...

The Monty Hall Problem is a probability puzzle based on the American TV game show Let's Make a Deal, made famous by Marilyn vos Savant's 1990 column in Parade magazine, in which switching doors after a reveal yields a 2/3 win probability.

Loopy is a loop-drawing logic puzzle, included in Simon Tatham's Portable Puzzle Collection, where players draw a single closed loop through grid dots using clues about how many loop segments border each cell.

Yajilin is a logic puzzle published by Nikoli where solvers draw a single continuous, closed loop through a grid. Numbered cells with arrows act as clues, indicating the exact count of black cells located in the specified direction along that row or column. All remaining cells that are not part of t...

The Tower of Hanoi is a mathematical puzzle invented by the French mathematician Édouard Lucas in 1883. It consists of three pegs and a stack of discs of differing sizes, with the objective of moving the entire stack from one peg to another while observing two rules: only one disc may be moved at a...

Tapa is a wall-shading puzzle invented by Turkish puzzle designer Serkan Yürekli in which cells are blacked out to create one connected wall, guided by clue numbers showing adjacent shaded-cell group sizes.

Cryptarithmetic (or cryptarithmetic) is a mathematical puzzle form, first popularized by Henry Dudeney in 1914 with SEND + MORE = MONEY, in which digits are substituted for letters in arithmetic equations.

Numberlink is a grid-based logic puzzle in which solvers must connect pairs of identical numbers using continuous paths. The rules typically dictate that paths must not cross or branch and that every cell in the grid must be occupied by a path. Popularized internationally by the Japanese publisher N...

Renban Sudoku is a variation of the standard Sudoku puzzle that introduces "Renban lines," which are often highlighted in a distinct color. The digits placed along each of these lines must form a set of consecutive, non-repeating integers, though they can be arranged in any order. For example, a lin...

Pentominoes are the 12 distinct shapes that can be formed by joining five equal squares edge-to-edge. First systematically studied by mathematician Solomon W. Golomb in 1953, pentomino puzzles challenge players to tile these shapes into rectangles or other specific configurations without overlaps. P...

The Blue Eyes Puzzle is a common-knowledge epistemic logic puzzle in which an arbitrarily large group of blue-eyed islanders must deduce and act on their own eye color once a public announcement triggers shared reasoning.

The N-Queens Problem is a classic combinatorial puzzle first published by chess composer Max Bezzel in 1848. The challenge requires placing N queens on an N×N chessboard so that no two queens threaten each other, meaning no two queens share the same row, column, or diagonal. Beyond its recreational...

Shikaku is a logic puzzle published by the Japanese company Nikoli, with a name that translates to "divide by squares" or "rectangles." The puzzle is played on a rectangular grid where some cells contain numbers. The objective is to divide the entire grid into non-overlapping rectangles and squares...

Battleships Puzzle is a solitaire deduction puzzle derived from the Battleship board game, in which the solver locates a fleet of ships within a grid using only row and column ship-segment totals and occasional revealed cells.

Retrograde chess analysis is the art of deducing the history of a chess position from its current state, with the field systematically developed by composer Thomas Rayner Dawson and popularized through journals in the early 20th century.

Skyscrapers is a logic-based combinatorial puzzle originating in Japan that is built on the Latin square mathematical model. The puzzle is played on an N×N grid where the objective is to fill each cell with a height from 1 to N without repeating numbers in any row or column. Numbers placed around th...