Welcome to
SudokuXP

@paulspages.co.uk


(Click here for details of new features in SudokuXP5)

Whether you're a beginner or an expert, SudokuXP is the best place for sudoku on the web. Here's why!
 

Great choice of puzzles





 

 

 

  • 20,000+ puzzle database
  • Random puzzle generator
  • Type puzzles in from magazines etc
  • Import/export puzzles as text
  • Detailed puzzle gradings
  • Advanced puzzle finder
  • Super-tough, rich puzzles
  • Tag your solved puzzles

SudokuXP has a database of over 20,000 (and growing) puzzles for you to choose from - and if that's not enough, its built-in puzzle generator can create an unlimited number of puzzles right there on your desktop. You can also type in puzzles from newspapers, magazines etc, paste them as text from emails, forums and websites, and export them for saving, emailing and posting online.

All SudokuXP's puzzles are generated from scratch (we don't use number-swapping techniques to produce 'clone' puzzles) and are guaranteed to have just one solution. They're graded from 'very easy' to 'outlaw', depending on the difficulty of the solving techniques needed to complete them, and given a toughness rating, based on a detailed solving analysis, which tells you how much work is involved in getting through them.

SudokuXP's database contains around 4,500 puzzles at each of the main grades ('easy', 'moderate', 'hard' and 'extreme'), so there's plenty to practice on as your skill develops (there are also 1,000 Outlaws if you really like a challenge!). The Advanced Puzzle Finder lets you find puzzles that contain the solving techniques you're studying. Puzzles are presented in 'gallery' pages - pick one you like, and print it or solve it on screen.

SudokuXP's 'extreme' and 'outlaw' puzzles are really tough - some of the toughest you'll find anywhere. Its 'constraint-neutral' puzzle generator ensures that they're rich too - many of them require 15 or more complex patterns to solve, rather than just a single tough technique then a simple run to the end.

All puzzles except those graded 'outlaw' are guaranteed to be solvable by logic alone, and SudokuXP will guide you, step-by-step through solving them (see below). When you've solve a puzzle, you can tag it as solved (with your own star rating and comments), so you won't find yourself solving the same puzzle twice. If you want to revisit a solved puzzle, you can see sortable lists and gallery displays of the ones you've tagged.

 

 

Great help and guidance

 

 

 

  • Vague hints with 'scratch panels'
  • Full hints with on-screen graphics
  • Links to comprehensive solving guide
  • Solver log for full solving script
  • Replay hints
  • Auto-hint (see it solved!)
  • Powerful analyzer
  • Long list of solving techniques

Whether you're a beginner or expert, SudokuXP gives you the best solving guidance you'll find anywhere.

Wherever you are in a puzzle, click the 'Hint' button and you'll get help with the next solving step. You can choose how much help to get - 'vague' hints tell you just a bit about the next move, with 'scratch panels' that reveal more details, while full hints tell you exactly what to do next.  If you want to see a hint again, you can go back to it, stepping back all the way to the start of the puzzle if you like.

SudokuXP's puzzle analyzer supports solving techniques from basic crosshatching to the fearsome Forcing patterns, Nishio and Nice Loops, with unique on-screen graphics to show how everything fits together. Solving technique names are hyperlinked to their description in SudokuXP's online solving guide, so you're one click away from a full explanation.

The solving log provides an audit trail of the steps taken to solve a puzzle - you can even click 'auto' in the Hint panel, watch SudokuXP solve the puzzle for you, then read about it afterwards!

 

  Great solving tools

 

 

 

  • Keyboard or mouse controls
  • Auto and manual candidate lists
  • List and positioned candidates
  • Candidate checker and fixer
  • Puzzle snapshots, save and restore
  • Resizable puzzle grid
  • Colour squares and candidates
  • Flag (filter) candidate values
  • Crosshatching Assistant
  • Full undo
  • Custom solving orders
  • Save your settings

From beginner to expert, SudokuXP lets you choose the tools you want for solving puzzles.

You can enter information using the keyboard or mouse, and choose between three sizes of puzzle grid. Candidate lists - vital for solving tough puzzles - can be automatic, or manual for you to maintain yourself. Lists can be displayed in basic '12345' format, or in the positioned format favoured by many experts, or made invisible if you want to really go it alone. SudokuXP can check your manual candidate lists and fix errors for you, too.

Crosshatching is the first step to solving any puzzle, and SudokuXP's unique Crosshatching Assistant, which draws the crosshatching lines for you, helps you to understand this most important of all solving techniques. Expert solvers can colour squares (and individual positioned candidates), and flag squares containing a selected candidate value. Really expert solvers can even change the order in which SudokuXP applies solving techniques when analyzing puzzles.

Solving sudoku isn't always a quick process, and you don't always get it right first time. SudokuXP's Undo button lets you 'unsolve' squares right back to the start of the puzzle, and you can take instant snapshots of the puzzle then restore them if things go wrong. You can even save the current puzzle state to SudokuXP (right down to individually-coloured squares), then restore it to a different computer!

If all that sounds complicated, don't worry! Getting started in SudokuXP is as simple as pressing 'Get a Puzzle' then typing numbers in. The advanced features are there if you want them, but they never get in your way - in fact you won't even see them until you show them by clicking on a grey bar.

Once you've got SudokuXP set up exactly how you like it, you can click 'Save Settings' and have your settings stored away. Next time you log in - even if it's on a different computer or browser program - things will automatically be put back the way you like them.

 

  More great features
 

 

 

 

From beginner to expert, SudokuXP lets you choose the tools you want for solving puzzles.

  • Printer-friendly pages. Show the current puzzle in a format suitable for printing, complete with candidate lists. Also, create a Selection Box print page with four or six puzzles at your chosen difficulty ratings.
     
  • 4X4 and 16X16 puzzles. Complete with their own puzzle galleries and many of the features of the 9X9 program, including hints and print pages.
     
  • Alternative symbols. Try solving sudoku using 'HBJDKTGSM' instead of '123456789' - it's not so easy!
     
  • Flexible candidate import/export. Export full-detail candidate maps for posting on forums,  mailing to friends or pasting into other sudoku programs - and import them too. SudokuXP's flexible importer accepts formats from most other programs.
     
  • Puzzles of the Day. Each day puzzles are picked from the database to be the 'Puzzle of the day' in the different toughness categories. Choose a toughness rating, try the puzzle and discuss it with other solvers in the SudokuXP Forum. And if you miss a day, you can find it later in the POTD Archive. (Note that stocks of POTDs do sometimes run out, particularly in Outlaws)

If all that sounds complicated, don't worry! Getting started in SudokuXP is as simple as pressing 'Get a Puzzle' then typing numbers in. The advanced features are there if you want them, but they never get in your way - in fact you won't even see them until you show them by clicking on a grey bar.

Once you've got SudokuXP set up exactly how you like it, you can click 'Save Settings' and have your settings stored away. Next time you log in - even if it's on a different computer or browser program - things will automatically be put back the way you like them.

 

Click here to read the SudokuXP news pages and user guide.

OK, now for the money bit...

Access to SudokuXP is by subscription only. The good news is that it doesn't cost much - all this, with unlimited* use, for a one-off payment of 3.00 (roughly $5.90 USD!). Generate and print as many puzzles as you like, anywhere in the world, with no daily or monthly limits - and nothing more to pay!
Please note that, due to VAT regulations, SudokuXP membership is not available to residents of EU member states other than the UK - we're very sorry for this.

* Subject to our fair usage policy. Puzzles are licensed or non-commercial use only. See our terms and conditions for details.
 

We accept credit/debit cards and PayPal.

Click here to become a SudokuXP member now!

or

Try before you buy with SudokuXP's Puzzle of the Day

(A special version that plays the Puzzles of the Day from SudokuXP's database, with all the SudokuXP hint, rating and solving features).
 

Q&A

What exactly is SudokuXP?
It's a set of web pages which generate, play and solve sudoku puzzles. It runs on Internet Explorer (6.0+), Mozilla Firefox and other compatible browsers (but not on Opera). Access is by subscription (one-off payment). There's no need to install any special software or browser plugins. As a subscriber you can log in to SudokuXP from any computer, provided it has a compatible browser and has javascript and cookies enabled.

Why are you charging for SudokuXP?
Because it's taken me a long time to develop it! It also costs me to have the pages online, and (in particular) for the bandwidth to download them.

What about the old version? Will that still be free?
For the time being, yes, although that may change.

How long will I have to wait to get access to SudokuXP?
About 30 seconds! As soon as PayPal has cleared your payment, you'll be a fully paid-up SudokuXP member, with full access to the system. (Note that the exception to this is payment by eCheque, which can take a few days to clear).

You say it's a one-off payment, but how long will you keep the pages online?
Not forever, because I probably won't live that long. So that everyone knows where they stand, I'm guaranteeing to keep SudokuXP available online for at least one year from the date of the latest subscription. So if you subscribe today you get a guaranteed year, and if someone else subscribes tomorrow, you get an automatic extension. In practice I hope to keep it going for many years - my paulspages.co.uk site has been going for over eight years now.

I haven't got a PayPal account - can I still join?
Yes - PayPal does the credit/debit card handling for SudokuXP, but you don't need a PayPal account to pay by card. PayPal will ask if you have an account with them, and if not they'll display a screen for you to type in your card details. Your card details are never transferred to my site - it all stays within PayPal's secure site, where everything's encrypted and safe.

Why do you want my email address as my username?
I got the idea from other sites I've registered with - email addresses are easily remembered and unique, so make ideal usernames. I won't give your address to anyone else, or use it to send you details of SudokuXP updates unless you say it's OK to do that. 

Why is there that warning about not using the same password as I do for banking? Isn't your site safe?
Like most leisure/hobby websites, SudokuXP isn't a high security site, which means, for example, that passwords aren't encrypted while they're being sent from the login page. As a general rule, you should never use the same password for accessing non-encrypted sites as you do for secure sites such as banking, PayPal, personnel systems etc.

I can't afford 3. Can I have membership for less, or even free?
Sudoku @ Paulspages gets visitors from all over the world, and I understand that in some places 3 is a lot of money. If that applies to you, please contact me (see below) and I'll see what I can do. If you're running a school in the third world and you want to print out puzzles to help your children's mental development, you can definitely have a free account. If it's a question of paying me 3 or having to wait another week for a leather carry-case for your iPod, then that's different.

Why do EU residents have to pay 3.60, while non-EU people only pay 3?
I have to charge VAT at 20% on all my sales to EU residents. 60p is a big chunk out of 3, so I've had to add it on rather than absorb it. Non-EU residents don't have to pay VAT, although strictly speaking they may have to pay their own local sales tax on this 'import'.

I am a non-UK, VAT-registered EU business and I want to pay input VAT at my local rate.
OK, if you really want to save the difference in VAT on 3, email me with your VAT number and trading address and I'll send you a tax invoice.  We cater for everyone here at paulspages.co.uk!

Why have you called it SudokuXP with that daft italicised XP? Is it a dig at Microsoft?
Yes, although I also thought of calling it the sPod and painting it white (with a special scratched-screen effect so you couldn't see the puzzles properly). I italicised the XP so I'd look like a big corporate outfit that'd paid an expensive branding consultancy to tell them to do it. I told myself, and saved a fortune. What's more I've changed my mind and stopped doing it now (so it's plain 'SudokuXP'), just like a real corporate outfit would.

Why couldn't you have written a proper application program, not just a web page?
SudokuXP is a proper application - it's got as much program code as a stand-alone product would have. What's more, applications delivered over the web like this are the way of the future (Microsoft says so, so it must be true!). Consider these advantages:

For more details, see the terms and conditions. If there's anything else you'd like to ask, please contact me at .

Paul Stephens, November 2005.
Updated July 2010.