Sudoku X is a variation of classic Sudoku that adds two extra diagonal rules. You still solve a 9x9 grid using the numbers 1 to 9, but both main diagonals must also contain each digit exactly once.
This small change makes the puzzle feel different from regular Sudoku. A number must fit its row, column, 3x3 box, and sometimes one of the two diagonals. That gives you more clues, but it also creates new restrictions to watch carefully.
Sudoku X is also known as Diagonal Sudoku. It follows the normal Sudoku rules and adds an X-shaped constraint across the grid. The two long diagonals, from corner to corner, must each contain the numbers 1 to 9 without repeating.
If you already know how to play classic Sudoku, Sudoku X is easy to understand. The challenge is learning when the diagonals help you and when they limit a number that would otherwise look possible.
Classic Sudoku uses rows, columns, and boxes. Sudoku X uses those same rules, then adds two diagonals. This means diagonal cells carry extra information.
The diagonals can remove candidates that would be legal in a normal Sudoku puzzle. For example, if the top-left to bottom-right diagonal already contains 5, then no other cell on that same diagonal can be 5.
This is useful because it gives you another way to eliminate numbers. However, it also means you must check diagonal cells more carefully before placing a digit.
Each level helps you practice a different part of diagonal Sudoku logic. Start with the level that matches your solving experience.
Sudoku X is a good choice if you enjoy classic Sudoku but want one extra layer of logic. The rules are simple enough for beginners, while harder levels can still challenge experienced solvers.
If you are new to Sudoku, start with Easy Sudoku first. If you already understand the basic grid, try Easy Sudoku X and learn how the diagonal rules change the puzzle.
It can be harder because diagonal cells have extra restrictions. However, those same diagonal rules can also give helpful clues.
The X refers to the two main diagonals that cross the grid from corner to corner. Each diagonal must contain the digits 1 to 9 without repeating.
Yes. The center cell is part of both diagonals, so it is often an important cell in Sudoku X puzzles.
Yes. Beginners can start with Easy Sudoku X after learning normal Sudoku rules. The diagonal rule is simple, but it should be checked carefully.
Sudoku X adds a clean diagonal twist to the classic puzzle. Use the normal Sudoku rules, check both diagonals, and solve the grid one logical step at a time.