(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
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.
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• Great help and guidance
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!
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• Great solving tools
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.
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• More great features
From beginner to expert, SudokuXP lets you choose the tools you want for solving puzzles.
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.
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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:
Runs on any computer with a compatible browser.
SudokuXP is in regular use on Windows (95/98/2000/XP), Macintosh and
Linux systems - and probably a few others we haven't thought of!
There's nothing to install (not even a
browser plugin). No disk space required, and no extra entries clogging up your
Windows registry!
You can use it on multiple computers. Log in at
home, in the office, at a friend's, in a cafe.
You're always up to date - when we add new features,
you get them automatically. Members who subscribed to the original SudokuXP
now get 4X4 puzzles, Undo and Save/Restore - and they haven't had to do a thing.
It moves with you to your new computer. Avoid the
nightmare of transferring applications from your old PC!
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.