Sudoku Tips and Strategies

Hi! My name is Steve, and I am a Sudoku enthusiast. My wife would likely use a different adjective.

I have studied how to solve a typical 9x9 Sudoku puzzle at some length, and have developed a modest but powerful repertoire of potential tips for human solving of a Sudoku puzzle using logic.

The goal of these pages is not only to provide those tips to others, but also to learn new ways of looking at the puzzles.

Hopefully, these pages will invite a free discussion and exchange of ideas regarding manners and methods to humanly solve sudoku puzzles.

Please check out the conventions that I use to label the puzzle grid, and other aspects of language used - including the rules of Sudoku as I see them. This will aid greatly in uniformity of discussion here.

Some Sudoku Definitions

Candidates
The integers 1 through 9
Cells
Small containers that in a solved Sudoku will contain exactly one candidate each. This is one of the normally unwritten rules
Boxes, Rows, Columns
Large containers of cells.
The rule
In a solved sudoku, each large container will contain exactly one of each candidate.
Each Sudoku puzzle has a unique solution.

If the number of cells in each large container equals the number of potential candidates, (as is the case with typical 9x9 Sudoku), the following statements are equivalent:

• There must be at least one of each candidate in each large container
• There can be no more than one of each candidate in each large container
Most techniques employ both of these ideas.

Sudoku Puzzle Coordinates

This is completely arbitrary, but I prefer the algebraic notation like that used with chess. Thus the bottom left corner cell is a1, and the top right corner cell is i9. Unfortunately, there is very little uniformity regarding Sudoku puzzle coordinate choices across the web. One can argue that one is better than the other, but they are all completely arbitrary. Additionally, the boxes are defined by the label of their center cell. Thus, the bottom left corner box is Boxb2, or Bb2.

I have created lots of posts on different solving techniques. Here are some to get you started: