Sudoku Level 20

The Hardest Sudoku Puzzles in the World

Sudoku Level 20 puzzles are widely regarded as the most difficult Sudoku puzzles in the world. With very few numbers already filled in, these 9x9 grid puzzles require the most advanced strategies and techniques to solve.

At Sudoku99, you can play Level 20 Sudoku puzzles online for free. Simply click on the puzzle you want to solve, and use your most advanced deduction skills to fill in the remaining cells with numbers from 1 to 9.

Our Level 20 Sudoku puzzles are designed to push even the most experienced Sudoku players to their limits. They require expert-level strategies such as the Almost Locked Sets, Unique Rectangles, and Kraken techniques, and require a very careful and methodical approach.

Playing Sudoku online is a great way to challenge yourself and improve your mental agility. Sudoku99 has a range of puzzles to suit all levels of experience, from easy to expert. So why not try our Level 20 Sudoku puzzles today and put your skills to the ultimate test? Can you solve the hardest Sudoku puzzles in the world?

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Sudoku Level 20 ( Expert - Gold : 17 clues )

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- Ranking 00:02:57

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Sudoku is a logic-based puzzle game played on a 9x9 grid. The goal of the game is to fill every cell of the grid with numbers from 1 to 9, in such a way that each row, column, and 3x3 subgrid contains all the numbers from 1 to 9 exactly once.

In a 17-hint Sudoku puzzle, the puzzle designer provides the player with only 17 clues or starting numbers on the grid. This makes the puzzle extremely difficult to solve, as the player must use advanced deduction techniques and logical reasoning to fill in the remaining cells.

To solve a Sudoku puzzle, players must use logic to determine which numbers can go in each empty cell based on the numbers already placed in the grid. Some of the techniques used in solving Sudoku puzzles include:

1.Scanning: Players scan the rows, columns, and 3x3 subgrids to find cells where only one number can fit.

2.Pencil marking: Players mark possible numbers in each cell, based on what numbers are already in the same row, column, or 3x3 subgrid.

3.Cross-hatching: Players use pencil marks to eliminate numbers that cannot go in a particular row or column, based on what numbers are already in the same 3x3 subgrid.

4.Naked and hidden singles: Players use logical deduction to determine which numbers must be placed in particular cells, based on the numbers already in the same row, column, or 3x3 subgrid.

5.Naked and hidden pairs, triples, and quads: Players look for groups of two, three, or four cells that can only contain a particular set of numbers, and use that information to eliminate other possibilities from those cells.

6.X-wing, swordfish, and jellyfish: Advanced techniques that involve looking for patterns across multiple rows or columns, and using those patterns to eliminate possibilities from certain cells.

7.Almost locked sets: Another advanced technique that involves identifying sets of cells that can only contain a particular set of numbers, and using that information to eliminate possibilities from other cells.

In a 17-hint Sudoku puzzle, players must use a combination of these techniques, along with other logical reasoning skills, to fill in the remaining cells and solve the puzzle. The difficulty of a Sudoku puzzle is often measured by the number of hints provided at the beginning of the puzzle, with 17-hint puzzles being among the most difficult to solve.