Best Sudoku Variant

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...

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...

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...

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...

Skyscraper Sudoku is a logic puzzle variant that combines standard Sudoku rules with a spatial visibility constraint. Solvers place digits from 1 to 9 into a grid, treating each number as a building of that specific height. Numeric clues provided outside the grid's perimeter indicate how many buildi...

Irregular Sudoku, frequently called Jigsaw Sudoku, is a logic puzzle variant that modifies the structural regions of standard Sudoku. Instead of the traditional nine 3x3 boxes, the grid is partitioned into irregularly shaped regions of nine cells each. The solving objective remains to fill the grid...

Little Killer Sudoku is a Sudoku variant in which clues placed outside the grid indicate the sum of digits along specified diagonals. Unlike standard Killer Sudoku, where cage sums constrain grouped cells, Little Killer Sudoku allows digit repetition along diagonals because diagonal cells are not bo...

Sandwich Sudoku is a Sudoku variant in which additional clues placed outside the grid indicate the sum of the digits positioned between the 1 and the 9 in each row and column. The name derives from the concept that the intervening digits are sandwiched between those two values. Standard Sudoku rules...

Between Lines Sudoku is a logic puzzle variant designed for enthusiasts of constraint-based grid deduction. In this format, digits are placed along line segments that connect two circled endpoint cells. The numerical value of every digit along the line segment must fall strictly between the values o...

XV Sudoku is a logic puzzle variant that applies mathematical constraints to a standard Sudoku grid. Orthogonally adjacent cells may be marked with an X to indicate their values sum to 10, or a V to indicate their values sum to 5. In many variations, the absence of a mark between adjacent cells indi...

Palindrome Sudoku is a variant of Sudoku that adds one or more designated lines to the standard 9×9 grid. Along each marked line, the sequence of digits must read identically in both directions, meaning the digit at one end must match the digit at the opposite end, the second digit must match the pe...

Samurai Sudoku is a Sudoku variant consisting of five overlapping 9×9 Sudoku grids arranged in a quincunx pattern, with the central grid sharing one 3×3 box with each of the four surrounding grids. The combined puzzle spans a 21×21 cell area, though overlapping regions are counted only once. Each of...

Anti-King Sudoku is a Sudoku variant that adds a spatial constraint inspired by chess to the standard 9×9 grid. In addition to normal Sudoku requirements that each row, column, and 3×3 box contain digits 1 through 9 exactly once, the anti-king rule prohibits identical digits from appearing in any tw...

Nonconsecutive Sudoku is a mathematical logic puzzle that applies an additional global constraint to the standard Sudoku grid. While solvers must still ensure that each row, column, and 3x3 box contains the digits one through nine without repetition, a specific spatial restriction is enforced. No tw...

Consecutive Sudoku is a logic puzzle variant that adds specific spatial constraints to the traditional 9x9 Sudoku grid. In this puzzle, a thick line or bar is used to mark the border between any two orthogonally adjacent cells that contain consecutive numbers. The defining mechanic is that the absen...

Dutch Whispers Sudoku is a logic puzzle variant of standard Sudoku in which adjacent digits along specifically marked lines must differ by at least 4. It is named as a variation of the more restrictive "German Whispers" Sudoku, where the difference must be at least 5. This rule requires solvers to u...

Clone Sudoku is a variant of the classic logic puzzle that introduces specific spatial constraints. In this version, designated pairs or groups of identically shaped regions are outlined within the larger grid. These regions must contain the exact same set of digits arranged in the exact same relati...

Sum Frame Sudoku is a Sudoku variant in which numerical clues are placed outside the grid. Each clue gives the sum of the first three digits encountered in the corresponding row or column when read inward from that side, adding arithmetic constraints to the standard placement rules. Solvers use thos...

Rossini Sudoku is a variant of the standard Sudoku puzzle that incorporates directional arrows placed outside the grid. These arrows indicate that the first three digits in the corresponding row or column are arranged in strictly ascending or descending order pointing toward the arrow's direction. T...

Toroidal Sudoku wraps the grid so that opposite edges connect, causing rows, columns, and sometimes boxes to wrap around the grid as if on the surface of a torus.