Sudoku

Sudoku Instructions:
Here's how to play Sudoku:
Place the numbers from 1 - n once in each row, column and bold-lined region within the grid. Typically the puzzles are 9 x 9 and therefore the numbers to be placed are 1 - 9 and the bold-lined regions are 3 x 3 boxes.

More About Sudoku

Sudoku is the most common and widely published of all logic puzzles. Yet it is relatively recent, having only been published in the UK since around 2005. It has a longer history: it was first published in the United States under the name of Number Place several decades earlier. Then it went to Japan under the name of Sudoku where some modifications were made to it (for instance imposing a requirement that there is symmetry in the grid and that no more than 32 givens are included at the start of the puzzle). Apparently the name translates roughly as 'number singularity'. If any Japanese speakers can give a more accurate translation (or indeed correct this), then please do let us know.

The history of the puzzle moving back to the West comes with Wayne Gould presenting the puzzle to the Times and everything took off from there, with a period of a year or so where anything that mentioned the word sudoku being a guaranteed best-seller, whether it be a book, computer game or some other sudoku-related product.

Why is sudoku so popular? It's a common question, and the answer is hard to find above and beyond 'because it is', however there are a few factors that seem to have particularly helped it become so popular. These include the fact that the rules are so incredibly simple: just place these numbers once in each region. That's it! Many puzzles have much more complicated rules, and generally the more rules a puzzle has, the more it switches people off.

Additionally, the fact that the puzzle comes 'part solved' in that the grid already has several numbers in it, seems to appeal to the need in many people to complete the puzzle. Whereas the grid of most logic puzzles starts empty, being partially filled seems to encourage people to want to complete it.

Finally, the puzzle is of course independent of needing any mathematical ability: the numbers could be substituted with any sort of simple, and the fact it is a pure logic puzzle appeals to many.

Another reason not so universally acknowledged is that it is pretty trivial to write a program to generate sudoku - a decent programmer could write a generator in one day. Now, to write a program that is good at grading and ensures only fair puzzles with a range of graded algorithms that mimic how a human solves takes a lot longer and a lot of time and effort, but many off-the-shelf generators are considered good enough by many mainstream publishers. This means that supply is no problem, and price is also very low, and that also helps. Contrast with a puzzle such as hanjie that is another pure logic puzzle but that requires the creation of artwork as well as a decent generator program, and sudoku becomes even more appealing to a publisher.

So these are reasons why sudoku is popular. Of course, there are other puzzles that seem to match up to these same criteria but are much less popular and common, but a lot of success with a puzzle seems to come down to being in the right place at the right time: with other popular puzzles being word-based such as crosswords and wordsearches, there was a place for a logic puzzle in the market. Had one of the other Japanese logic puzzles been introduced to a mainstream newspaper before sudoku, perhaps that one would have taken the world by storm instead!

There are various variants of sudoku, either straight variants whereby simply the grid size changes (with 9x9 considered the standard puzzle), whilst others build on sudoku by adding either other regions or other rules: see related puzzles for these.

If you'd like to try a Sudoku puzzle, you can have a go with our Online Sudoku Player.

Last updated: 14 Feb 2012

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Sample puzzle:
start Sudoku image

Sample solution:
solution Sudoku image

View a sample Sudoku PDF

Play Sudoku Puzzles:

To play sudoku puzzles online, visit the Sudoku puzzles page at the PuzzleClub with hundreds of puzzles to play.

If you prefer to play with pencil and paper, then we have various options for you with PDF magazines you can download and print, which are:

4x4 Sudoku Magazine
6x6 Sudoku Magazine
Fiendish Sudoku - a collection of tricky 9x9 puzzles.

Our Puzzle Magazines site also contains a range of sudoku puzzles at larger grid sizes.

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