# Sudoku Variants

A Sudoku puzzle is defined as a logic-based, number-placement puzzle. The objective is to fill a 9×9 grid with digits in such a way that each column, each row, and each of the nine 3×3 grids that make up the larger 9×9 grid contains all of the digits from 1 to 9. Although the 9×9 grid with 3×3 regions is by far the most common, many other Sudoku variations exist. Other variations include additional value placement constraints, alternate symbols (e.g. letters), alternate mechanism for expressing the clues, and compositions with overlapping grids.

We’ve compiled the following list of Sudoku variations,

## Diagonal Sudoku

It is another type of standard Sudoku. Based on standard Sudoku, diagonal Sudoku has more requirements. Numbers on two sides of diagonal lines have to be numbers from 1-9 and cannot be repeated. Since diagonal Sudoku has more requirements, the solving process is more challenging and interesting. It also has more requirements related to players’ observation capacities.

## Hyper Sudoku

Hyper Sudoku follows the same rules as Sudoku in that every row, column and block of the grid must contain the numbers “1” to “9”. But it has an additional four shaded blocks (referred to here as “hyperblocks”), each of which must also contain the numbers “1” to “9”.

## Killer Sudoku

Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. The difference is how you arrive at those numbers.

In killer sudoku, no numbers will be filled in at the start. An in addition to the rows, columns and 3x3 regions, every cell is also a part of a cage, indicated by different colors. Each of these cages has a sum, and you must work out what numbers to put in each cell based on the sum of the cage. Each cell in a cage is added up and must match the sum of that cage.

## Samurai Sudoku

Samurai Sudoku (often only referred to as Samurai or Gattai-5) are a partial overlapping arrangement of five standard Sudokus. The four corner Sudokus are arranged around a central Sudoku, in such a way that each of the four corner Sudokus shares a block with the Central Sudoku. This creates an x-shaped figure with a total of 369 cells, which are distributed over 41 blocks.

The individual Sudokus, in particular the central Sudoku are usually a bit easier to solve, since the blocks, which two Sudokus are sharing can be more easily completed.

Other variants combine eight (Gattai-8), thirteen (Gattai-13) or more Sudokus. These variants are also known as Monster Samurai. Furthermore there are Samurai Sudokus which combine different Sudoku variants together.

## Jigsaw Sudoku

Jigsaw Sudokus (also known as Irregular, Nonomino, or Geometric Sudoku) are very similar to regular Sudoku puzzles, but instead of 3x3 blocks, they are divided into irregular jigsaw-like shapes. Each row, column and jigsaw shape contains all of the digits 1 thru 9.

## Greater Than Sudoku

The puzzle has no givens. Instead, there are greater-than (>) signs between some adjacent cells, which signify that the digit in one cell should be greater than another. All other ordinary Sudoku rules apply.

## Odd/Even Sudoku

An Even/Odd Sudoku is solved just like a Sudoku by filling the numbers from 1 to 9 into the blank cells. The darker grey cells are only for even numbers and the lighter grey for odd numbers. Even/Odd Sudoku is easier then a classic Sudoku.

## Center Dot Sudoku

The center cell of each box makes an additional group, meaning the blue cells must contain digits 1-9.

## Clueless Sudoku

A Clueless has 9 constituent Sudokus, in a 3x3 formation. The center box of each constituent Sudoku has no given digits. Together, these center boxes form a 10th Sudoku, without any given digits. This central Sudoku is essential in solving the puzzle, as it can pass eliminations from one constituent Sudoku to another.

Which Sudoku variant will you try today? Please comment below.

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