Hard Sudoku Puzzle Online 3-4

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Advanced Sudoku strategies go beyond the basic techniques and require a deeper understanding of the puzzle. Here are some advanced strategies that can help you solve more challenging Sudoku puzzles:

1. Naked Pairs and Naked Triples:
   • Look for cells within a block, row, or column where only two or three cells can contain the same two or three numbers. If you find such a group, eliminate those numbers from the rest of the cells in the block, row, or column.
2. Hidden Pairs and Hidden Triples:
   • Search for groups of two or three cells within a block, row, or column where only two or three numbers are candidates. Even if there are other candidates in those cells, if you can determine that those numbers must appear in those cells, you can eliminate them as candidates from the rest of the block, row, or column.
3. X-Wing:
   • This strategy applies when you have two rows and two columns, each containing only two cells with the same candidate numbers. If the candidates form a rectangle in the grid, you can eliminate those candidates from the rest of the rows and columns.
4. Swordfish:
   • Swordfish is an extension of the X-Wing strategy. It applies when you have three rows and three columns, each containing two or three cells with the same candidate numbers. If you can find a pattern resembling a “fish,” you can eliminate the candidate numbers from the intersecting rows and columns.
5. XYZ-Wing:
   • This strategy involves three cells with a specific candidate number in a chain of relationships. If removing that candidate from one cell would force another cell to have a certain number, you can make eliminations based on these relationships.
6. Coloring:
   • Coloring involves using two colors (e.g., red and blue) to mark candidate cells. If two cells in the same group (block, row, or column) share a candidate and they belong to different color groups, you can make deductions based on the candidates’ relationships.
7. Chains and Loops:
   • Chains and loops are advanced techniques that involve creating a chain of linked cells with common candidates. By examining these chains or loops, you can make eliminations or conclusions about other cells in the grid.
8. Skyscraper:
   • Similar to the X-Wing, the Skyscraper strategy identifies two columns with two candidate cells in each column. If the candidate forms a “skyscraper” shape in the grid, you can eliminate the candidate from the corresponding rows.
9. XY-Wing:
   • This strategy involves three cells with specific candidates in a chain. If the presence of these candidates in the chain forces a particular elimination, you can use this information to solve the puzzle.
10. Unique Rectangle:
    • Look for situations where four cells form a rectangle and have the same two candidates. If these conditions are met, you can eliminate one of the candidate numbers from other cells in the same row or column.

These advanced Sudoku strategies require practice and patience until you can master Advanced Sudoku Puzzles.

Hard Sudoku Puzzle Online 3-4

When you complete the crossword correctly a message will tell you “Congratulations, you have completed the puzzle If you have completed the puzzle and don’t get the “Congratulations” message, one or more of your answers are wrong. Click on Check in the top left corner to see your errors to correct.

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