I've decided that developing my own blog system (this site for example) further is not worth the effort, especially since when I originally used an off-the-shelf one (WordPress) my pages appeared much higher up the Google results! (1st or 2nd page, not page 25 or something like that!) - and that by the way was with exactly the same actual text content, at least originally.

It never made complete sense to post on killersudoku.org.uk when talking about more than just Killer Sudoku, so I've decided to combine this update with a much-needed overall of the slight embarrassment that was garethmoore.co.uk - so just pop over to garethmoore.co.uk and you can start reading my new puzzle blog! There probably won't be any further updates to this particular blog.

I've started the ball rolling with a combination 9x9 and 6x6 Samurai Sudoku puzzle, so check it out!

Gareth

PS Some of my blogging code lives on in the puzzlemix.com comment pages, so it wasn't an entirely wasted effort! :)

1 attachmentThis week I thought it would be fun to make some new Sudoku using 8-way symmetry. I thought I'd start off with a special 13-grid puzzle where you can really see all the reflections. The effect of the 8-way symmetry is that every one of the 13 sub-grids has at least 2-way symmetry even when considered on its own.

Important: This 'Complete Samurai' puzzle is not like standard Samurai puzzles - in this one in addition to the rows and columns of the 13 grids, every single run of 9 digits in a row or column from one bold line to another must contain 1 to 9. So for example if you count 4 squares right and 7 squares down from the top-left of the puzzle, then you must place 1 to 9 into that row of 9 squares running right from that point - and so on throughout the entire puzzle. Good luck!

(Attachment is a PDF, so you should be able to print it fairly easily - you might want to look to see if your printer driver has a 'tile' or multi-page option to print over several pages however!)

1 attachmentQuite a while since I added a new puzzle here, so since I have a spare jigsaw sudoku sitting around I thought I'd upload it here. :) Have fun!

Last night I added 100 Toroidal and 100 Jigsaw Sudoku puzzles to puzzlemix.com - and someone has already added both of them to their account, which is great! They slowly increase in difficulty, and for the jigsaw there are a range of different region designs.

I do have some new code that lets you optionally hide the side panel in the player too, but I decided not to make that live until I have made it pop out again when you complete the puzzle - otherwise I suspect people will stop ranking and commenting on puzzles so often!

There have also been a tonne of small incremental improvements to the comments page recently. They are now full of lovely statistics about how people have done on the puzzle, and another column full of your own stats - now you can see in detail what solving aids you used and so on, plus a range of time details if you've completed a puzzle multiple times. Lots of the stats only expand out when they differ from a more general case, so the page doesn't get too long most of the time. Plus with additional puzzle-specific annotations for anyone who comments on a puzzle it's also fun to see people complaining that a puzzle was too easy whilst noting that they took forever and had to use all the solving aids...

I also had to remove the dokakuro.com and dosudoku.com forums last night because they yesterday filled with the most appalling spam - and this after having had no spam for well over a year after I rewrote the registration page code so that scripts couldn't auto-fill the variables. I decided with them being rarely used there was no point wasting time trying to add even more anti-spam protection (they already required email confirmation, hidden text in an image, had changed variable names and so on) so I have taken them off-line, probably forever. If I ever decide to add a central forum to puzzlemix then I might back-propagate that to dokakuro. Or I might not. :)

Which is also a similar reason as to why comments are disabled on killersudoku.org.uk (i.e. here!) at the moment - sorry about that. I will post when I re-enable them, with better spam protection!

1 attachmentYou can now play Jigsaw Killer Sudoku in my latest interactive puzzle player over at www.puzzlemix.com!

I have had this ready for a long time, but I was planning on making it slightly neater - if you look closely you can see that sometimes the cages shift in position slightly depending on the width of the lines surrounding each square (because the jigsaw regions are irregular). However I've decided that probably noone else will ever notice... or care if they do! :)

I've been making lots of new puzzles and will fairly soon be adding lots of regular Hitori, Slitherlink and Jigsaw Killer to the daily puzzles section, as well as occasional Giant Slitherlink. I will also add lots of specialist puzzle books full of static sets of puzzles of your choice, so if you just want difficult Jigsaw Killer puzzles then you can get just those.

But the best value will always be the daily puzzles section, with over 1,000 puzzles in each subscription!

I've added a couple of special Christmas puzzles to puzzlemix - Happy Christmas!

There's now a Slitherlink player on puzzlemix, adding yet another new type of puzzle to the site!

There are also now more puzzle samples in the non-interactive part of the site, which I intend to revamp separately when I have the time.

There are now Hanjie puzzles on puzzlemix - at last! I've been working on this for a while.

I have added lots of puzzles to appear once a month in the free section, plus another 52 puzzles to appear once a week in the daily puzzles section (obviously I'll add more once the year is up!), and I have 100 more puzzles ready which tomorrow (or very soon) I will add to a separate 'book' subscription for online play.

PS Sorry commenting here on killersudoku.org.uk is disabled - I was getting a lot of disgusting spam here and I need to take the time to add in a working spam-rejection system.

I put up lots of new stuff on puzzlemix.com over the weekend.

The really big news is new puzzles! This update adds Hanjie, Hitori and Killer Sudoku to the site. There has been a preview of the Killer Sudoku player on the homepage of the site for a while now, but the Hanjie and Hitori players are brand new and I'm really pleased with them. As of Monday I also added highlighting to the current row and column in the Hanjie player, which makes it much easier to use with bigger puzzles.

There are various changes to the players, including keyboard shortcuts for undo and redo (Z and X) which are very useful. You also now get the chance to rate a puzzle when you 'give up' on it, which should stop the ratings being biased to those who can actually finish a puzzle!

There is now a much improved puzzle listing system which lets you filter and sort the display in all sorts of ways, as well as limit the number of puzzles that are shown either per page or in total to a time period and quantity of your choice. It also shows you more information about how many people have managed to solve each puzzle.

The site also finally has detailed instructions on how to play each puzzle, so if you're not familiar with these types then now you can be - and there are also full instructions on how each player works, if you want to take full advantage of all the advanced features.

Lots of very minor issues are fixed in the update too - for example if you double-click a number to place it in Apple's Safari browser you would previousl select the whole puzzle; this doesn't matter but it looks ugly. This is fixed in the new update. There are about 20 minor fixes too, such as stopping the 'Check solution' button flashing when you 'undo' from a full grid until you next hit a number key. You'd probably never notice these things, but they're fixed anyway.

There's a great change in the helper for Kakuro and Killer Sudoku - now you will find that the 'show current clue fits' option will cross out eliminated fits for you, thus making it much easier to see what possible fits are left. It no longer shrinks the list if you have 'dynamic clues' turned on, since with this change this is no longer helpful.

The Hitori player has a feature I promised a long time ago elsewhere - to auto-highlight squares that need to be shaded since they have already been placed as 'definitely clear' elsewhere in a row or column. It's quite fun just to hold down the mouse button and run your pointer round the puzzle watching them flashing on and off as squares shade and unshade again... or maybe that's just me!

That's just a selection - you might spot more changes as you use the updated puzzlemix!

Now there's one thing remaining in the immediate future - I need to add the puzzles to the puzzle subscriptions, so you can actually play Hitori, Hanjie and Killer Sudoku outside of the samples on the home page!

1 attachmentOn the basis that something is better than nothing, here's a Samurai Sudoku puzzle to (maybe!) get the ball rolling again!

Also keep a look out for the new design Sudoku Pro that will be in the shops in under 2 weeks - it now has an extra colour throughout, and is physically quite a bit bigger and is on much nicer paper. I'm looking forward to getting my copy!

After a year away (apart from a couple of weeks at Christmas) I am now back in Britain. I am very busy at the moment with various projects but there should be some updates some point in the next month or so! If you have any requests, please let me know.

Sorry for the total lack of updates for 2 months - I've been off travelling around Australia and French Polynesia, and I'm in fact currently in Papeete, Tahiti. Shortly I'm off to various places in the US for over a month but maybe I'll find time to upload a couple of puzzles... We'll see! :) If you have any requests let me know and I'll work on those first. After I finish travelling, towards the end of the year you should find a lot of updates to both puzzlemix.com and this site too. And that's a promise! :)

Sorry for the lack of recent puzzle posts - I've been off travelling up in tropical parts of Australia. It was supposed to be hot up there, but just a couple of days ago in the Whitsundays it was the coldest June day since records began, so that was a well timed trip! It rained a lot. Anyway, off even further north in a couple of days again for another couple of weeks, so I'm afraid there won't be many puzzles here for a while.

But the good news is that I've worked on and off on puzzlemix.com content and I now have a nearly-complete Hitori player, which will also support Nurikabe with a little tweaking and then be, I think, a good stepping stone to a Hanjie player. I also still need to add some killer sudoku to the database so they show up in user puzzle subscriptions, but that's pretty easy since I have the puzzles all ready - I might also put in some Killer X and Killer Jigsaw if I have time.

I've also updated the Kakuro and Killer solving assistant so that it crosses out the number fits that are no longer useful - this is one less thing you might want real pencil and paper for when solving the puzzle, so I think this is really useful. I've stopped it shortening the number fits when you turn on 'dynamic clues' too, since this was hard (confusing) to combine with the new crossing-out feature. This change isn't live on the site yet but I really hope to get time to make this live before I go away again on Thursday.

You might also have noticed that a couple of weeks ago I updated the way the site stores the rankings and comments you can enter from the completed puzzle page. These are both now done via AJAX so that there aren't any nasty page reload issues or chances to lose a part-written comment; I also rewrote the puzzle list update so that now the window will never reload when the puzzle state changes. Previously when you opened, saved, completed and rated a puzzle it would reload the puzzle list menu - now it updates it from Javascript directly, even when you add a comment. This works if you open the puzzle from the comment page too. This will matter to you most if you have a relatively slow connection (like I do in Australia!). Puzzlemix also now asks you to confirm before you replace a currently-open puzzle by clicking on another one from the puzzle menu - previously it would replace your current game without checking.

The next Sudoku Pro is almost ready too, with Fillomino as puzzle of the month - that will be the issue after next from the current one. I had good fun making the Fillomino, which I'd never tried before, and I hope there's a good difficulty level progression. You'll have to wait for the magazine to find out though!

You can now play Killer Sudoku on puzzlemix.com - currently just from the front page samples, but I'll be adding puzzles to the weekly and daily puzzles soon!

Check it out and let me know if you have any comments!

1 attachmentToday I fixed the ragged right and bottom puzzle edges that the new Jigsaw and Toroidal puzzles had in Firefox or indeed any standards-compliant non-Internet Explorer browser, and also (I think!) finally got rid of the annoying 'auto-completion' popup that Firefox sometimes shows when entering numbers in the grid. It does this because I steal the input focus to a hidden textbox in order to prevent the backspace key sending you to the previous page (it's the shortcut for 'back' in most browsers). I do this in the first place because this turned out to be the most cross-compatible way of doing it (worked in IE, Firefox, Opera and Safari that is!). It also helps keep the tab key from tabbing into the URL bar in some browsers if you use that to move from square to square. Anyway, I've changed the type of text field so now it shouldn't offer these pop-up number lists.

I also noticed that the overall ratings column was missing from the comments pages, so that's now been added in. And (finally) the toroidal player now says Toroidal at the top not Jigsaw (oops).

If you haven't tried out the new players then pop over to puzzlemix and give them a go - I'm really interested in any feedback!

I've also attached a new Nurikabe puzzle - this one is hard, so beware!

Well, the new toroidal and jigsaw players are now up on the puzzlemix.com site, with samples on both the front page and also in the weekly puzzles section for a year from today. However there's only one of each in the weekly section - if you want regular new ones you need to subscribe to the daily puzzles. Every Saturday and Wednesday a new toroidal or jigsaw (alternating) will appear in the daily puzzles section, in addition to the existing two daily puzzles (so not instead of).

I've also added the ability to comment on a puzzle directly to the completion dialogue, so now you can write a quick comment without any hassle thanks to some nifty dynamic CSS changes and an AJAX POST to connect to the database. I'm really pleased with how it came out because I didn't want to make the dialogue box too complicated. Even the 'Save comment' button only appears if you type something, and it goes away again once you have. It waits for confirmation that the comment has been saved correctly first, of course.

I did some work on an improved rankings page before (the site actually keeps track of exactly how many times you use each of the solving assistants, which I want to allow users to filter by), which I will hopefully get online sometime soon. But now I think that's enough for today - it's 1:45am here in Sydney!

As I just mentioned in a comment a few posts down, today I added the missing layout code to the puzzlemix player code so it can now display jigsaw (and toroidal) sudoku. I've said previously that the player supported this but I hadn't yet written the relatively tiny bit of code to display the grid puzzle on the screen appropriately (shift the borders and colour the squares if appropriate) - well I finally did get round to this and now I just need to upload some suitable puzzles to the site and it will be live immediately. That's an 'immediately when I get round to doing that final bit', mind you, but it should be in the next few hours. (Unless I get distracted with adapting my Nurikabe designer/solver to support Fillomino!)

I also added support for Sudoku X regions in any of the puzzle types, which it now renders as a fine mesh overlaid on the background colours (rather than changing the colour of the square) - this means I can put up Toroidal X, Jigsaw X and so on without needing any new code next time round. It does mean that existing Sudoku X puzzles display slightly differently, but I bet noone notices unless they're on a very low-resolution display!

The only other major thing I mean to add to the Sudoku player now is support for Killer Sudoku - as I've also said previously, the Kakuro code I already have supports Killer Sudoku (it's all one player with internal switches for different types of puzzle) so it's a relatively straightforward case of adding the display of the region totals to the layout and then plugging these into the player code. Then you'll be able to play Killer Sudoku with all the advanced solving tools available in the Kakuro player - dynamic clue recalculation, lists of number combination fits and so on. And Killer X and even Killer Jigsaw.

The player already supports Sudoku puzzle sizes other than 9x9, as the Futoshiki 5x5, 6x6, 7x7 and 8x8 puzzles demonstrate. I might add some 6x6 Sudoku and variants to puzzlemix at some point too.

Finally, mentioning Futoshiki reminds me - it already supports Inequality Sudoku, because this is basically what Futoshiki is without the box regions, so I should add some of those to the site too. But one thing at a time, I think!

2 attachmentsI thought it would be fun to post some puzzles I've just made with my new Nurikabe editor, so I've attached two puzzles. Both are definitely on the tricky side, so if you've not tried Nurikabe before these probably aren't the best place to start! The larger 15x15 one starts off okay but the final part (the bottom) involves quite a few deductions about what must go where. The 8x8 is surprisingly tricky for its size and maximum clue value, although maybe you'll find it easier than I did!

The rules are pretty straightforward: shade in squares so that each number remains in a white 'island' of the specified number of touching squares. Each white island cannot touch any other island, and all the shaded squares must make up one single continuous area. You also are not allowed to form any 2x2 or larger blocks of black squares - this is an important restriction without which these puzzles would have many different answers. Squares are considered to touch if they are adjacent horizontally or vertically. Solving the puzzle mainly stems from working out which squares must be black in order to avoid the shaded squares being split into separate regions, as well as how the white regions must progress in order not to touch any other white island. Good luck!

1 attachmentTo round off today's series of puzzles (I must be feeling generous?!) here's a Hanjie puzzle I made a little while ago. The numbers at the top and left tell you how many consecutive sequences of shaded squares there are in a row or column. Each sequence of shaded squares must have a gap of at least one square between it and any following sequence. So for example '2,3' means there are 2 shaded squares followed by a gap of at least one square followed by 3 shaded squares. I'm sure you can find more detailed instructions on the internet somewhere if you need them! :)

If you want a clue: "End of the line".

2 attachmentsNow I'm up to the giddy ranks of page 7 of google's results for "Killer Sudoku" (whoo!) it might be time to have a couple of actual Killer Sudoku puzzles too!

4 attachmentsTo make up for not posting any puzzles for a week (see previous post), here is a mix of 4 different Sudoku types!

1 attachmentI haven't posted any puzzles for a week. This is mainly because the past week was when I finished off the next issue of Sudoku Pro (puzzle of the month is Nurikabe), but I've also been working hard on some Nurikabe code. I don't want to generate the puzzles automatically (I've not yet seen properly satisfying automatic Nurikabe), but what I do want is a solving assistant which can help validate puzzles rapidly - and that's what I now have. My solver can currently solve almost every puzzle I've found, and what's more it does it in small incremental steps using a variety of human methods so it can rate it accurately by difficulty. Like with most puzzles it's not astoundingly hard to write a solver (although it's more tricky than say Sudoku), but writing one that works like a human would is much more interesting (that's a euphemism for challenging!). I'm never just interested in whether a puzzle has a single solution (although if it doesn't then it is useless) - I want to know that it is fair to solve. And, of course, that it actually has a valid solution. Anyway, with Nurikabe it turned out that my first approach didn't scale well to larger grids so I had to rewrite a good chunk of it to 'remember' what it was doing, and then it turned out that this was still a bit slow so I had to rewrite a chunk of that new chunk too. Thus it took a while to complete! I can still think of two solving strategies I haven't implemented, but other than that I think it can solve pretty much what I can personally solve. It only really gets stuck with enormous regions right next to each other where which region joins to which area can only be decided right at the conclusion of the puzzle, and frankly I find those pretty challenging myself! I've been testing my personal solving speed on the Nurikabe samples on Nikoli's site, and found I beat the example time in all the cases so was quite pleased with that. I think Nurikabe, like quite a few logic puzzles, is one of those where you get massively faster with a bit of practice.

The upshot of all this waffle is that I am planning to add Nurikabe to puzzlemix.com sometime in the next few months. I'd say much sooner but I have a lot of travelling planned, so am not sure how much time I will have. I'll also be adding Hitori for sure at the same time (I already have a huge stack of Hitori puzzles and the core players will be very similar). All of which reminds me that I really should get round to adding jigsaw and toroidal sudoku, which are already supported by the players. I also want to add in killer sudoku but I need to come up with a sane way of showing all the pencilmarks alongside the clues first!

1 attachmentAfter the other day's Slitherlink I thought why not have another non-Sudoku puzzle, so here's an 8x8 Hitori. I made this ages ago and I rated it 'level2' in some long-forgotten rating scheme so I forget if it was particularly tricky or not - I expect it's not that hard at all. It might even be a bit boring... but I'll print it out later and give it a go!

The rules are simple - shade in squares so that there is no more than one of any number in a row or column. Shaded squares can't touch horizontally or vertically, and all the unshaded squares must form one single continuous area (i.e. you can travel from any unshaded square to any other unshaded square purely by moving horizontally or vertically between touching squares).

1 attachmentI don't think I've posted a Slitherlink here before, and whilst it's not in any sense a Sudoku puzzle I thought it might be quite fun to do so! This isn't especially hard, although of course if you've never solved one before you might find it so!

The aim is to draw a single loop by joining the dots using only horizontal and vertical lines. The line cannot cross or in any way touch itself, and it must have as many adjacent segments to each number as specified by that number, so a '0' has no line segments next to it and a '3' must have three line segments next to it. It's not necessary for the loop to visit every dot.

2 attachmentsI'm back from my latest trip(!) and so it's now time to post the 7x7 Toroidal Sudoku I promised a week ago. These are a little harder than the 5x5 ones but so long as you keep careful track of which shapes connect together around the edges they shouldn't be too difficult, especially if you can already conquer the 9x9 ones. I seem to find with toroidal Sudoku I inevitably make a mistake at least once when solving them by getting confused about which regions continue where which makes them artificially harder - but maybe that's just me! :) I even managed this with the 5x5 ones...

2 attachmentsHere's something that's different, and also something I promised a little while ago. Two 5x5 Toroidal Sudoku - the aim is to place 1 to 5 into each row,column and wrap-around bold-lined region. The regions wrap around the edges of the puzzle, so where they go off one side of the puzzle they continue directly opposite. It takes a bit of thinking about but it's satisfying when you get there!

I'm off again for a few days (up to the Hunter Valley/Port Stephens region of New South Wales) but when I get back I'll post some 7x7 Toroidal Sudoku. In the meantime the 5x5 will be good practice for that, or even the 9x9 I posted previously!

2 attachmentsJust to keep the toroidal fans going, here's another couple of Toroidal Sudoku puzzles. Can you fit 1 to 9 into each row, column and marked shape? The marked shapes 'wrap around' from one edge of the puzzle to the directly opposite side. This is easier to see when the regions are coloured as in a previous example I posted a while back, but I haven't had time to remake this puzzle in colour so if you prefer it that way (I do!) then you'll need coloured pens or something like that... :)

2 attachmentsThe aim of these puzzles is to fit 1 to 9 into each row, column, 3x3 and both marked diagonals, whilst placing numbers so that each dashed-line shape contains numbers that add up to the total given at the top-left of it. You also cannot repeat a number within a dashed-line shape.

3 attachmentsI promised to post some puzzles ASAP and then failed to do so, so to make up for it here are not 1, not 2, but 3 2-grid Samurai puzzles to get your teeth into. The aim is to fit 1 to 9 into each of the rows, columns and 3x3 boxes in the two overlapping grids. You will need to solve both grids together in order to complete the puzzle.

Edit: I can see that I need to edit the web code to put the puzzles side-by-side not stacked-on-top, but that will have to wait until I get back from my next trip (starting tomorrow) to Canberra for a few days! :)

I've just got back from Tasmania, so over the next couple of days I will be posting some new puzzles at last! Sudoku Pro 19 just went off to the publishers and this month's master class puzzle is Toroidal Sudoku - there are 4x4, 5x5, 7x7 and 9x9 puzzles to provide some variety and a gentle difficulty curve up to the 9x9. I might post some variant size Toroidal here at some point too.

Whilst away I wrote pagination code for puzzlemix.com so if your list of subscribed puzzles has got long and is taking a while to reload then that will be sorted out when I get a chance to upload it to the live site.

Just a quick note to apologise for the lack of recent puzzles - I'm currently away visiting Melbourne and Adelaide, although today I'm off to Kangaroo Island (which is the third largest island off the coast of Australia - it's an hour or so south of Adelaide in South Australia) for a few days.

More puzzles in about a week, hopefully!

1 attachmentMaybe this will work better than yesterday's 4-grid version, which didn't have enough overlap between the grids to make it interesting.

In this version you need to solve two 9x9 puzzles that are adjacent but do not overlap. However some of the jigsaw regions do overlap. The aim is to fit 1 to 9 into each of the rows and columns of the two grids (marked by the purple line in the centre), whilst also fitting 1 to 9 into each of the jigsaw (coloured) regions.

1 attachmentI had an evil idea first thing this morning. What if you placed Sudoku puzzles next to each other but didn't make them overlap? Not very exciting in itself, but what if you then placed jigsaw regions so that they overlapped between the puzzles to link them all together?

Well, this is the first result. The overlap is very small indeed - just two squares overlapping between each of the regions, but it's enough to make the puzzles dependent on one another! Ideally I'd like to overlap them more but this is what I managed in the amount of time I allotted this morning to give it a go.

In case it isn't clear, there are 4 9x9 grids all next to each other but not overlapping. Only the jigsaw regions overlap. The purple lines show where the 9x9 grid boundaries go, where appropriate.

Good luck!

It's finally ready! www.puzzlemix.com now has a fully-functioning online puzzle subscription system where you can sign up for free and get (currently) a new Sudoku, Sudoku X, Futoshiki and Kakuro puzzle every week. I've filled the database up with a year's worth of puzzles to start the site off. You will also be able to sign up for a further puzzle subscription to daily puzzles for a small fee (although this isn't actually active right now because I haven't added any of these to the database yet).

You solve the puzzles online using my advanced in-browser players which don't require Flash or any further downloads to work. Not only this, however, but you can also rate each puzzle and view the ratings assigned by other users, or flip over to the rankings page to see full details on average, best and worst solving times. In addition each puzzle has its own comments page where you can discuss the puzzle with other users. I'm also planning to add a more general discussion area in the future.

The puzzles vary in difficulty and, in the case of Futoshiki and Kakuro, size, although I'm hoping to add other Sudoku sizes in future too.

I'm really keen to hear of any thoughts or suggestions (or problems, although I hope it is all working perfectly!). Is the number of weekly puzzles about right? They expire after two weeks but if you play the puzzle in that period then it stays in your account forever. The reason they expire unless played is because otherwise you could sign up one day and then come back a while later to a very large amount of free puzzles.

Is a daily subscription of interest? What puzzles would you like to see? My sudoku player can handle any shaped regions (so it can do jigsaw, toroidal, etc) and arbitrary summation regions (so it can do killer sudoku along with all the kakuro solving tools once I work out how best to display the regions and totals!), so it is in principle possible to add most of the variations you see on this site. But large puzzles won't fit in the window so well!

Mostly irrelevant to this site, but I've started up a random thoughts blog over on glm.org.uk. So far it consists of pretty technical comments on Windows Presentation Foundation (WPF) and the odd web-coding thought, but there'll be the occasional puzzle-related piece of news there from time-to-time too as I work on my plan for world domination...

More news soon on puzzlemix.com too, I hope - I have a fully-working version here with puzzle subscriptions, comments, ratings, publication and expiry dates and the whole kaboodle. I'm just busy right this very moment filling it with enough free puzzles to last a year, so hopefully it should go properly live soon.

1 attachmentOkay, well this one looks positively tame after the previous circle of grids, but hopefully this will be a little easier. It's all about lulling you into a false sense of security (or something like that...).

Fit 1 to 6 into each of the rows, columns and 2x3 boxes in each of the 4 grids in this plus shape. The centre is deliberately empty - there's no 5th grid lurking there to be discovered.

The only confusing aspect is the overlap between the puzzles, which is two-thirds of several of the 2x3 boxes.

1 attachmentIf you've seen a Samurai Sudoku like this before then I'll eat my metaphorical hat! I've just been fiddling about with different grid layouts on paper and thought I'd try out a circle of 6x6 grids (on the basis that probably noone would have the patience to solve a circle of 9x9 grids, although I could be wrong on that!).

I haven't actually tested this out myself to see how well it works having made it (it's been checked electronically so it should be perfectly solvable however!) so I don't know how long it will take - I'm guessing an average of about 15 minutes but we'll see...

I've also got a semi-circular version too that I haven't posted yet.

If you'd like me to try out any other new Samurai variants then just send me a list of coordinates for the top-left corner in cell offsets (eg a 2-grid 9x9 samurai has grid 1 at 0,0 and grid 2 at 6,6).

Anyway, let me know how you get on!

1 attachmentNow here's a puzzle I haven't made before, which is actually based on two recent suggestions for more killer sudoku and more extra regions sudoku. I thought I'd combine the two, and so this is the result!

You can probably deduce the rules for yourself, but just in case: place 1 to 9 into each row, column, 3x3 bold-edged box and 3x3 pale red box. You must place numbers so that each of the dashed-line cages adds up to the total at the top-left corner of it, and you may not repeat a number within a dashed-line cage (this is a really important rule!).

Good luck!

The layout works in Firefox now (I'd accidentally left a height setting in which Internet Explorer was ignoring but Firefox was honouring), and the RSS feed now contains the puzzles as well as just the descriptions! It also has the paragraph structure back, where present. I've also made the previous RSS feed location work too so you shouldn't have to re-subscribe. Plus I've fixed some of the existing comments which I'd attached to the wrong posts by mistake when re-creating the existing content. The edit comment dialogue now also returns you to where you were, and when you add an account it now sends you a copy of your username and password (plus a 'forgotten password' page has been added too). Hopefully that's everything sorted now!

1 attachmentOkay, so it's not the most exciting variation in the world but I do think they're quite fun - so here's another 5-grid Samurai Sudoku. As ever, fit 1 to 9 into each row and column and 3x3 square of each of the 5 overlapping grids! I'll work on some different variations for coming posts, but this is just to christen the new web system!

I got fed up with the blogging software I was using for this site so I've written my own! Now I get thumbnails of each of the puzzles displayed with each post, and none of the comments can get stuck attached to the file pages (as happened on some of the posts before). It's also much easier to use the site since there are no irrelevant options, and commenting is just a case of hitting the 'Add comment' button for an instant comment box. Similarly, viewing comments is now instantaneous thanks to the wonders of Javascript and CSS! The whole system should be much faster too - I found the previous site slow and unresponsive, and it was a pain to write messages and attach images.

If you had a user account before it will now have vanished so you will need to create a new one, but this is very very easy and then you'll never have to fill in any details again to post comments - also you'll be able to edit (and delete) your own comments if you want.

Here's what the killer sudoku blog used to look like.

I also now have the ability to schedule puzzles to appear ahead of time, rather than having to physically post each day I want a puzzle to appear. In principle this means I'll be able to post more puzzles - we'll see if this bears out in practice! :)

I've re-implemented the RSS subscription feed so there's a chance it might not work in every RSS reader, but it works properly in Internet Explorer and Firefox.

If you spot any problems then let me know, otherwise it's back to the puzzles now!

1 attachmentFollowing the success of the previous 5-extra-regions Sudoku puzzle, here's another to keep you going! The standard Sudoku rules apply, with the extra rule that each of the 5 pale red areas must also contain 1 to 9.

1 attachmentHere's a standard 5-grid Samurai puzzle. (The aim is to solve each of the 5 overlapping Sudoku grids simultaneously).

1 attachmentThis puzzle is a standard Sudoku with the addition of 5 extra regions, marked in pale red (or pink if you must!). Can you fit 1 to 9 into each row, column, marked 3x3 square and each contiguous pale red shape?'

1 attachmentHere's a larger-than-average jigsaw puzzle. Can you place 1 to 9 and A to C into each row,column and marked shape in this puzzle? The colours are just for decoration, but they do make it easier to see at a glance where each shape is. Good luck!

1 attachmentJust for a change, here's a Kakuro puzzle. The rules are simple: Fill each white square with a number in the range 1 to 9 so that each consecutive run of white squares adds up to the number at the top or left of the run. The key to the puzzle is that no number can be repeated within a run.

1 attachmentNow here's a challenge for any Sudoku masochists out there! It's 8 overlapping 9x9 grids with a symmetric Jigsaw pattern that wanders right across them all. You must fit 1 to 9 into each row and column of each 9x9 grid, as well as 1 to 9 into each coloured jigsaw shape.

Good luck! You really will need it for this one!!!

1 attachmentI'm still away but here's a puzzle to keep you going. It's a 5-grid samurai jigsaw puzzle. You need to solve all 5 grids simultaneously to solve it - the purple lines clarify where the 9x9 grids overlap (this helps because the jigsaw shapes cross over between grids).

If you're using Internet Explorer 7 then you should notice the orange 'RSS' icon at the top-right of the browser window light up on this site (just under the search bar). By clicking on it you can 'subscribe' to this site and keep track of when new puzzles and posts appear without having to check the site directly. It will appear in the 'Feeds' tab that you can choose when you click on the 'Favorites Center' Star icon at the top-left of the window. Other browsers and RSS feed readers are also capable of doing this too.

1 attachmentHere's an interesting puzzle, requested by 'Pickle' over on the BBC MindGames magazine forum. It's a 13-grid Samurai puzzle, and you must solve all 13 grids simultaneously!

Good luck! You'll need it! :)

I'm currently away from regular internet access whilst I'm travelling so apologies for the lack of new puzzles for the past couple of days. Hopefully I'll manage to get a couple new puzzles up in the next day or so, but no guarantees! If there's any particular types you'd like to see then do please let me know and then I'll focus on those. I'm assuming that unusual types are of the most interest but perhaps it's more basic variants that you'd prefer to see? Let me know!

1 attachmentThe site is called 'Killer Sudoku' so maybe it's time for an actual Killer Sudoku puzzle... so here's a jigsaw one! Can you fit 1-9 into each shape, row and column whilst obeying the region totals? No number may be repeated within a dashed cage. It's not as hard as you might think, once you get your head round it!

1 attachmentHere's an interesting puzzle. 5 grids overlap - can you solve them all simultaneously? Don't forget the 'hidden' one in the middle!

Naturally I have the solutions to these puzzles which I can post, but I'll wait until someone comments that they need one. :)

1 attachmentLet's start off with this. It's not that tricky really, once you get your head round what you need to do!

Place 1-6 into each row and column of the three overlapping grids. Place 1-6 into each coloured shape.

I thought it was about time to start posting more of my puzzles online. I've had www.dokakuro.com, www.dofutoshiki.com and www.dosudoku.com (the last a bit more basic in appearance) for a while, but all my more exotic puzzles have remained within the pages of books and magazines. Now with this site I'm going to correct that.

This site's not just for Killer Sudoku, it's for Killer Sudoku - that is, awesome Sudoku! Well that's the aim, anyway.

My Sudoku puzzles - and countless variants! - have appeared in a wide range of places including Total Konzai, Sudoku Pro, Total Sudoku, BBC MindGames, BBC Radio Times and countless books. See www.puzzlemix.com for some of my publications.

To date, the most elaborate and colourful specimens have been seen in BBC MindGames - where else have you seen a 3-grid jigsaw 6x6 samurai stack puzzle, or a full-colour enormous samurai jigsaw? And not both in the same magazine, I'd bet.

So here we are. This is an experiment but we'll see where it goes. I'll start off shortly with a big colour puzzle and we'll take it from there. Please do comment on posts and the site - I'm making this up as I go so I'll pay attention to what you say!

Gareth