Best Logic Puzzle

A hidden pattern of colored pegs provides the central challenge in Pressman's editions of Mastermind. One player sets the code and the other makes successive guesses, using feedback to narrow the possibilities. Black markers identify correct colors in the correct positions, while white markers indic...

Nurikabe asks solvers to divide a grid into numbered islands and a connected shaded sea. Originating in Japan, it has been published by Nikoli since 1991. Each unshaded island must contain exactly one numbered cell, and that number specifies its total area. Islands connect through shared edges and m...

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.

Restoring a cube shape is part of the challenge in Meffert's Ghost Cube, a shape modification built around a standard 3x3x3 mechanism. Its pieces have irregular outlines and different depths, so turns transform the assembled cube into an uneven arrangement of protruding parts. A successful solve req...

Corner turns give Meffert's Skewb a different feel from a conventional face-turning cube. Invented by Tony Durham and commercialized by Uwe Meffert, it rotates around four diagonal axes passing through opposite corners. A single twist moves corner pieces and face-center pieces together, rearranging...

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 combines the familiar Sudoku grid with sum clues resembling the arithmetic element of Kakuro. In the usual 9x9 format, cells are grouped into outlined cages, each marked with a target total, often without any starting digits. Every row, column and 3x3 box must contain the digits 1 to 9...

Published by the Japanese puzzle company Nikoli, Fillomino requires a grid to be divided into connected numbered regions called polyominoes. Every cell in a region carries the same number, and that number equals the region's total cell count. Starting clues provide some values, while the remaining n...

Developed by HAL Laboratory and published by Nintendo, Picross 3D brings nonogram-style deduction into three dimensions on the Nintendo DS. First released in Japan in 2009, it presents a solid arrangement of blocks with numerical clues along its rows and columns. Stylus controls let players mark blo...

Rubik’s Clock is a two-sided mechanical puzzle first marketed in 1988 and designed by Christopher Wiggs and Christopher Taylor. It has nine clock faces on each side, for 18 in total, and uses corner wheels and buttons to change the positions of linked hands; the objective is to set every clock to th...

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...

No Thanks! is a card game designed by Thorsten Gimmler and published by Amigo. Players take turns either accepting a face-up number card or placing a counter to pass it to the next player; cards add negative points, while unused counters reduce the score, and consecutive cards can be scored as a run...

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...

Ravensburger Labyrinth is a family board game designed by Max J. Kobbert and first published by Ravensburger in 1986. Players move pieces through a maze made from movable path tiles, shifting one tile each turn to change the routes before trying to reach assigned targets. The changing board combines...

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...