How to Figure Out Sudoku?

How to Figure Out Sudoku?

Sudoku is a one-rule puzzle that can either be incredibly simple or deceptively challenging. Different approaches help you solve different Sudoku puzzles, but before that, let’s clear your basics:

Cell: Individual square where a row and a column intersects

Row: Horizontal alignment of the cells, a.k.a. band

Column: Vertical alignment of the cells, a.k.a. stack

Box: 3×3 sub-square a.k.a. nonet or region

Group: Collectively referring to the row, column, and nonet

Given: Clues already provided

Candidate: Potential solution that isn’t provided

Method: Technique used to solve cells

Unique: One distinct solution

Difficulty: Complexity of the puzzle and the skills required

So, in short, nine cells or the individual squares group together to form a 3×3 sub-box in a standard 9×9 grid having nine total boxes and 81 cells. Darker lines for easy identification further separate each box.

Rules of Sudoku

To understand the techniques of solving a Sudoku, it’s essential to know the rules. So, you’ve to start filling each row, column, and 3×3 sub-grid with numbers from 1 through 9 without repeating them. No matter the difficulty of the puzzle, the grid comes with some numbers sprinkled all over. Any Sudoku puzzle to be termed as unique will have at least 17 cells prefilled. Based on these, you begin deducing the digits that fit in.

Solving Sudoku

The trick is to begin with the lowest level of logic, eventually moving up to the more advanced methods. Some of the common strategies for solving free Sudoku puzzle games include:

Naked Single: In a particular cell, one last possible digit remains to be placed, leaving no other hidden candidates.

Naked Pairs: This elimination method concerns the situation where two digits are potential candidates in a given group. These are then excluded from other cells within the group.

Hidden Single: For a given digit, there’s only one cell left to place that digit. And the correct number is hidden amongst the rest.

Locked Candidate: This works in two ways:

  1. If the candidates of a specific number are restricted to the row or column of a block, that digit cannot appear outside of it.
  2. If all candidates of a particular number are limited to a block, the number can be eliminated from other cells in that block.

X-Wing: Find two rows and columns such that all candidates of a particular number in rows are contained in columns, and the numbers which aren’t a part of columns can be eliminated. This works for cells comprising a rectangle. Exchange the terms rows and columns for getting X-Wing for vertical columns.

Swordfish: This works exactly like X-Wing, but the candidate may appear at the intersection of three rows and columns following specific rules.

Now that you’re aware of a few basic and advance Sudoku solving techniques, put these to test. Download any of the free Sudoku puzzle games available on the app stores and figure out how Sudoku works.


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