Anti-King - cells within a king’s move in chess must contain different numbers
Anti-Knight - cells within a knight’s move in chess must contain different numbers.
Battenburg Sudoku - everywhere 2 odd and 2 even digits form a 2x2 checkerboard pattern, a Battenburg marking is given.
Chains - The grid consists of a group of circles linked together in chains. The digits appear in each chain exactly once.
Disjoint Sets - the puzzle contains disjoint groups in the puzzle, one for each relative box position and no repeats may occur within groups.
For example, the cells at position 1 in their boxes form a region and contain distinct digits.
Extra Region - the puzzle contains an additional region.
Dots Sudoku - the centers of each box forms another region.
Windoku - contains additional regions. The “frame” of the window consists of R1, R5, R9, and C1, C5, C9. The remaining “panels” are the additional regions.
Jigsaw - regions are no longer subgrids, but rather irregular, connected shapes each consisting of cells.
Nonconsecutive - orthogonally adjacent digits may not be consecutive.
Schrodinger - place the digits respecting classical and any additional constraints. Two of the digits share a Schrodinger cell. Each row, column or box contains exactly one Schrodinger cell.
Unknown Regions - Regions are no longer subgrids. Divide the grid into regions of orthogonally cells that contain the digits .
Clone - cells in a clone must appear in all related clones (for example, all blue clone cells must be ). If the clone is more than one cell in size, all instances must be identical.
Consecutive Sums - clues outside the grid indicate the sum of all digits that have at least one consecutive digit as neighbor in the corresponding row or column
Descriptive Row / Column - along row / column X, the digits give the location of X on that column / row
For example a 4 in R4C5 with C5 as the marked column means that R4C4 = 5.
Descriptive Pairs - for each pair of clues (X,Y) outside the grid at least one of the following is true: X is in the Yth position from that direction; Y is in the Xth position from that direction
Equal Parities - within every cage / sub-region, the sum of the odd digits equals the sum of the even digits.
Japanese Sums - shade some cells such that the clues outside the grid indicate the sums of digits in contiguous sets of unshaded cells in the corresponding row or column.
Killer - marked cages MAY specify a number. No number can repeat within cages. Numbers in cages must sum to the specified total
Box Sums - one marked cell in each 3x3 box contains a digit which is the sum of the other marked cells in that 3x3 box.
Little Killer - numbers are placed outside the grid along with an arrow indicating the diagonal. Digits on the grid along the diagonal sum to the indicated total.
Look and Say Cage - the clue on the cage is read literally. For example if it says “09”, then there are “0 nines” in the cage.
Offset 1 and 9es - all digits right below the digit 1 indicate the distance (to the left or right) to the 1 in the corresponding row.. All digits placed right below the 9 indicate the distance to the 9 in the corresponding row
Outside Sudoku - clues appear outside of the grid. These must appear in the first 3 digits of the corresponding row or column (reading from that direction).
Frame - the numbers outside indicate the sum of the first three digits from that side
Minimax - numbers are placed outside of the grid. These indicate the sum of the lowest and the highest digits in the first three cells from that side.
Polyomino - divide the grid into polyominos. At least one cell in the polyomino must contain the size of the polyomino.
Rank - a digit “X” in a rank clue means that the digit in the cell is the Xth smallest digit in the corresponding cage.
Full Rank - a clue is given outside the grid. full rows / columns form -digit numbers read from the direction of the clue and the clue gives the rank with respect to the other numbers.
Rossini - arrows outside the grid indicate that the nearest three digits in the corresponding row are in ascending order (with respect to the arrow).
Sandwich - numbers are placed outside the grid. The number tells you how many digits are “sandwiched” between the and the .
Double Inverse Sandwich - clues outside the grid give the sums of the digits that are orthogonally adjacent to either the 1 or 9 in the row or column
Skyscraper - numbers are placed outside the grid. The number tells you how many digits are visible from it. Interpret digits as the heights of skyscrapers. A taller skyscraper obstructs a smaller skyscraper.
In other words, it tells you the first immediately visible run of increasing digits.
Symmetry - cells that are symmetric to each other must obey certain properties.
X-Sums - numbers are placed outside the grid. The number tells you the sum of the first digits where is the first digit placed along that direction
Parity Counter - clues outside the grid indicate the sum of the first digits as seen from that side, where is equal to the number of even / odd digits
X distance - digits outside the grid have to be placed in the corresponding row or column in the given order, where the second digit is placed X cells away from the first digit and X is the digit in the first cell of the corresponding row or column.
Difference - an edge is marked with a dot. Incident cells must differ by this amount.
Evens - cells with gray circles must contain odd digits.
Greater Than - edges may be marked with a symbol. This symbol points to the cell with the lower digit.
Kropki Black - cells separated by black dots must have a ratio of .
Kropki White - cells separated by white dots must contain a difference of .
LC Clues - numbers are formed by reading left-to-right / top-to-bottom. L clues separate two numbers summing to 50. C clues separate two numbers summing to 100.
Mathdoku - edge clues pertain to mathematical operators applied to cells incident to it. Constraints are applied based on these mathematical operators.
Maximum - a cell is marked as maximum, in which case neighboring cells must be smaller than it.
Minimum - a cell is marked as minimum, in which case neighboring cells must be larger than it.
Odds - cells with gray squares must contain even digits.
Quads - digits(s) within a Quad Clue (which occurs at the corners) indicate that the digit(s) must appear in one of the four neighboring cells.
Group Sum - the number in the Quad Clue instead, indicates the sum of the digits in the clue
Ratio - an edge is marked with a dot. Incident cells must be in this ratio.
Self-Referential Cells - the value of the cell gives the number of self-referential cells with that value
For example, there must be if the cell is , there are self-referential cells that have a value of .
XV clues - Cells separated by a V sum to 5. Cells separated by an X sum to 10. Cells separated by an XV sum to 15.