Anti Diagonal Sudoku
Classic sudoku rules apply. Additionally every main/marked diagonal contains only 3 different numbers.
Anti Knight Sudoku
Classic sudoku rules apply. Additionally no two identical digits can be a chess knight‘s move away from each other.
Arrow Sudoku
Classic sudoku rules apply. Additionally the number placed in a cell with a circle must be the sum of the numbers placed in cells the adjoining arrow passes through. Numbers may repeat on arrows.
Average Sudoku
Classic sudoku rules apply. If the number in a cell equals the average of its two horizontal neighbors then the cell is marked with a horizontal line. If the number in a cell equals the average of its two vertical neighbors then the cell is marked with a vertical line. All possible lines are marked.
Battenburg Sudoku
Classic sudoku rules apply. Additionally, everywhere if 2 odd and 2 even digits form a 2x2 checkerboard pattern, a Battenburg marking is given.
Consecutive Sudoku
Classic sudoku rules apply. Additionally adjacent cells containing consecutive numbers are marked. Adjacent cells with no marking must not contain consecutive numbers.
Consecutive Pairs Sudoku
Classic sudoku rules apply. Additionally, if a circle is given between two adjacent cells, then the two numbers in those cells must be consecutive.
Sudoku X (Diagonal Sudoku)
Classic sudoku rules apply. Additionally both diagonals must contain 1-9 exactly once.
Disjoint Groups Sudoku
Classic sudoku rules apply. Additionally cells with the same position in 3x3 boxes contains number from 1 to 9 i.e no number can repeat in the same position in 3x3 boxes.
Odd Even Sudoku
Classic sudoku rules apply. Additionally all the cells which can contain the even/odd numbers are grayed.
Extra Region
Classic sudoku rules apply. Additionally each group of nine colored cells must also contain the numbers 1 to 9.
Sudoku-SF
Classic sudoku rules apply. Additionally numbers outside the grid equal the sum of the digits appearing in the cells in the first box (till the next bold line) seen from that edge of the grid.
Jigsaw Sudoku
Place a digit from 1 to 6 in each empty cell so that each digit appears exactly once in each row, column and outlined region. Each outlined region is marked by thick borders.
Killer Sudoku (Sum Sudoku)
Classic sudoku rules apply. The sum of digits in cells inside every cage must equal the total given for the cage at the upper left cell. Digits do not repeat inside a cage.
Kropki Sudoku
Classic sudoku rules apply. Additionally if absolute difference between two digits in neighboring cells equals 1, then they are separated by a white dot. If the digit is a half of digit in the neighboring cell, then they are separated by black dot. The dot between 1 and 2 can be either white or black.
Little Killer Sudoku
Classic sudoku rules apply. Additionally numbers with arrows indicate sum of the numbers in each direction.
No Touch Suoku
Classic sudoku rules apply. Additionally, no same number can touch each other diagonally.
Non Consecutive Sudoku
Classic sudoku rules apply. Moreover no adjacent cell pairs (sharing an edge) can contain digits which are consecutive to each other.
Odd Even Consecutive Sudoku
Classic sudoku rules apply. Additionally adjacent cells containing odd and even numbers are marked. Adjacent cells with no marking must either contain both odd number or both even numbers.
Outside Sudoku
Classic sudoku rules apply. Additionally the digits outside the grid must appear in one of the first three cells seen from that edge of the grid.
Palindrome Sudoku
Classic sudoku rules apply. Additionally the digits in the squares with the line form palindromes.
Repeated Neighbours
Classic sudoku rules apply. Each shaded cell must have repeating orthogonal neighbours (neibhbours sharing an edge). White cells must have distinct orthogonal neighbours.
Rossini Sudoku
Classic sudoku rules apply. Additionally the arrows indicate that the nearest three digits in the row (column) are in ascending or descending order (increasing towards the direction the arrow is pointing towards). If there is no arrow outside a row/column, the nearest 3 digits therein cannot be in either ascending or descending order.
Series Sudoku
Classic sudoku rules apply. Moreover grayed cells can only contain numbers from the given series.
Snail Sudoku
Fill the grid with digits 1~4, so that each digit appears exactly once in every row, column and every 3x3 spiral. Digits should be placed orderly in the spirals, from the entrance to the center. The numbers outside the grid indicate the first seen number from that direction.
Tens Sudoku
Classic sudoku rules apply. Additionally all adjacent cells containing numbers adding to ten are marked with X.
Thermometer Sudoku
Classic sudoku rules apply. Additionally some thermometer shapes are in the grid; digits must be strictly increasing from the round bulb to the flat end.
Tight Fit Sudoku / 0-9 Sudoku
Classic sudoku rules apply. In addition, some cells are split by slashes (/) and must be filled by two numbers. In these cells, the smaller number must go above the larger number.
Touchy Sudoku
Classic sudoku rules apply. Additionally each digit has at least one consecutive adjacent (sharing edges) neighbor.
Trio Sudoku (147 Sudoku)
Classic sudoku rules apply. Additionally cells with circles must contain the digits 1, 2 and 3. Cells with squares must contain the 4, 5 and 6. Blank cells must contain the digits 7, 8 and 9.
X-Sums Sudoku
Classic sudoku rules apply. Additionally the clues outside the grid indicate the sum of the first X numbers placed in the corresponding direction, where X is equal to the first number placed in that direction.
XV Sudoku
Classic sudoku rules apply. Additionally if an X is given between two adjacent cells, the digits in those cells sum to 10. If a V is given between two adjacent cells, the digits in those cells sum to 5. If an X or V is not given,the two digits cannot sum to 5 or 10.
Pips Sudoku
Classic sudoku rules apply. Only some dots of dice/domino faces are given.
Sudoku <>
Classic sudoku rules apply. Numbers must be placed according to greater (>) and less (<) signs.
Toroidal Sudoku
Jigsaw Sudoku rules apply. Some of the outlined regions will wrap between the top and bottom edges, and/or the left and right edges of the grid.
Star Sudoku
Put the numbers 1-9 into the triangular cells so that each of 6 large triangles and every line (of any length, even uncontinuous) contain every digit 1-9 not more than once.
Pandigital Sudoku
Fill in the square with digits from 1 to 9 so that in each row, in each column, and in each 3x3 region all digits are different. Some rows and columns form correct arithmetic expressions reading from left to right or from top to bottom.
Product Sudoku
Classic sudoku rules apply. The product of the digits within each sub-region is equal to the specified number. Digits in a sub-region need not to be different from each other.
Digital Sudoku
Classic sudoku rules apply. Only some traces of the digit display are given.
Word Sudoku
Classic sudoku rules apply. Fill the grid with numbers ONE-NINE. Number of letters and some of the characters and their correct placement are given.
Cubic Sudoku
Fill in the cube so that every outlined region and every layer (as shown by the double arrows) contains the digits 1 through 8.
Multiple Sudoku
Classic sudoku rules apply. In any pair of two adjacent digits, if one is a multiple of the other, this is marked with an X. If there is no X, then the digits are not simple multiples of each other.
Shape Sudoku
Classic sudoku rules apply. Numbers should be assigned to the shapes presented in the grid based on the pieces given outside. These pieces may be rotated but not reflected, and each piece is used exactly once.
Color Sudoku
Classic sudoku rules apply. In the upper-left grid, numbers are given which represent the sum of clues in the indicated colors. A Red/Yellow/Blue number is a simple given in the corresponding grid. A secondary color (Orange = Red+Yellow) represents the sum of the numbers in the Red and Yellow grid. A digit in black represents the sum of the numbers in all three grids. No digit can repeat in the same place in two puzzles.
