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Sudoku.com - Number Games

What is Sudoku Evil?

Sudoku evil is a 9×9 grid sudoku puzzle with the highest possible level of difficulty. It’s an advanced level only for experienced sudoku solvers. Simple logic and basic knowledge of sudoku rules won’t cut it – you as a player should know advanced sudoku solving techniques and understand how to apply them in practice.

Even though evil sudoku is an extremely difficult game level, many experienced players find it the best way for brain training and developing mental skills.

How to solve Sudoku Evil?

The principle of the solution is the same as in the classic Sudoku. The goal is to fill the grid, so that each row, column, and 3x3 block contain all the digits from 1 to 9 without repeating. But in Evil Sudoku, there are much fewer numbers on the grid at the beginning. There's going to be only 4 or even fewer numbers. This fact makes the evil sudoku level extremely difficult to solve.

The best way to solve the evil sudoku puzzle is to start with the blocks where there are more prearranged numbers. Such blocks are easier to complete compared to the ones with fewer numbers.

Evil Sudoku Solving Techniques

While it's totally fine to play sudoku intuitively on the easy levels, evil sudoku requires the knowledge of some strategies. Here is the most popular one for solving sudoku on the evil level.

XY-Wing Strategy.

XY-Wing strategy is an advanced technique for eliminating candidates. Let’s review it with an example. Let’s say, there are 3 different cells with exactly 2 candidates (notes) each that are related to each other. The cell in the center is called the pivot. The two others are called the pincers. Each of these cells can include only one of 3 digits, named X, Y, Z. It means that any 3 digits can replace these letters.

The pivot contains candidates XY. The pincers - candidates XZ and YZ. Any cell that intersects both pincers can’t longer contain a candidate for digit Z, because the pivot means either of the pincers to contain this digit.

Why play evil sudoku?

Playing sudoku evil online has a lot of advantages. While solving sudoku, your brain exercises logic, learns to make decisions, and puts your memory to the test. Regularly playing evil sudoku is a good method of improving your concentration. Play 1 or 2 evil sudoku games every day and you will not have any problems with losing focus while doing important things.

Moreover, sudoku develops analytical skills and thinking. Regular game practice will teach you to pick up mental thinking models from sudoku and use them in real life while analyzing different situations.