Sudoku Solver: version 2.2

Welcome to the Sudoku (Su Doku) solver page, an economical utility for those who like to have their Sudoku problems quickly solved. This solver not only produces solutions, it allows them to be rapidly eMailed to multiple recipients: useful for those regular Sudoku competitions (such as the daily one The Times is currently running).

Version 2.2 has a very small charge associated with it, but gives a lot for the money! We're charging so that we can keep developing it. The old Version 1.3 is still available free. As a service, we also provide free grids for people who like to use pencil and paper.

Updates:

Some more grids have been added to the free items page.

There is now a Java version 1.0 available, which is both free and platform-independent. Click here for details.

Background

Sudoku (Su Doku) is a popular puzzle in Japan (appearing in puzzle magazines such as Nikori), and the rule is simple: fill a given grid with the numbers 1 to 9, so that every column, row, and 3x3 box indicated by the slightly heavier lines has the numbers 1 to 9. The name is frequently translated as 'number place' in English, although other names such as 'sole number' may be better translations. Of course, in English, the name has multiple spellings: Su Doku is a common alternative.

Solvers

There are a number of Sudoku solvers out in the web (search for the phrase in Google), but this version has been designed to make it especially easy to enter Sudoku competitions. The solver provides the following capabilities:

Integrated help, which includes an explanation of all the rules used for solving puzzles.
Enhanced input capability.
Improved screen appearance,
Saving and loading of puzzles and solutions.
Scan of input data for obvious errors.
Very fast solution times.
Identification of malformed puzzles.
A complete training mode allowing for step-by-step solutions, with commentaries.
Maintenance of multiple eMail templates.
Quick sending of a standard solution eMail from any template, so catering for multiple competitions.
Generation of text messages for use with non-SMTP mail systems.
Import of Pappocom .sud file format puzzles.
Full manual with rule explanation.

You can see screenshots of the new Sudoku Solver here.

How it works

The Sudoku solver is written in C++, and will attempt to solve all Sudoku puzzles deterministically by the iterative application of a sequence of ten rules. Four are classified as basic rules and six as advanced rules. These are applied repeatedly to generate a puzzle solution. For puzzles that have insufficient information the system will then generate guesses and look for inconsistencies deriving from the guesses. If the puzzle is malformed (ie cannot have a solution as it contains a logical contradiction) then the solver will identify it as such.

If the puzzle can have more than one solution then the system will return the first answer it finds. This can be seen in action by entering an all-blank grid.

The package

When installed, Sudoku Solver will put an icon on your desktop. You can run it by double-clicking on the icon. In the installation folder you will also find the manual, Sudoku.pdf. Sudoku Solver works on all versions of Windows.

Purchasing

Version 2.2 Sudoku Solver costs a mere 4.5 Euros including VAT - about the price of a pint of beer. You can buy it using PayPal, even if you do not have an account at present. The system will let you download the software immediately after payment.

Free version and other extras

If you really don't want to pay for the solver, then here are the free versions! We also provide free grids, and are starting an information service on Sudoku theorems.