There were quite a few comments from our visitors, especially on the Daily Killer Sudoku page, which makes that and other pages load slow. Therefore, I have moved some of the old comments to this new category.
If you’d like to read what other people had to say about our puzzles you may find the old comment by clicking on the “comments” link below or here.
UPDATE (some 5 years later): I reopened the comments on all pages. Feel free to add your comments there, it means a lot to me!
is this website for killer sudoku or just reg?
This website is both for Sudoku and Samunamupure (Killer Sudoku).
“Perfect Sudoku” software also solves & generates diagonal Sudoku (aka Sudoku X), plus different sizes of Sudoku, such as 4×4 or 5×5.
It is likely that there will be more Sudoku “mods” implemented, most likely “Samurai” puzzles.
Have only just discovered your website today, and as an avid “killer” fan, am really chuffed! How long have you been posting daily killers? And is it possible to get hold of the previous ones (can’t seem to find a link to old ones, other than yesterday’s solution). Keep it up!
Jane,
The Daily Killer Sudoku has been going on for 4 days. So you’ve only missed 3 puzzles. Anyway, you will soon be able to find all the puzzles in an archive, so don’t worry too much! 🙂
Further, you can download the Perfect Sudoku software and generate (registration required) your own Killer Sudokus!
Thank you for your support.
I have downloaded the software successfully, thanks, but can’t suss out how to register – I get a window saying I should enter the unlock key sent to me by e-mail. Can you help?
Jane,
click on the “registration” link under the “categories” menu on this page. You will find detailed instructions there.
Basically, in order to keep this site up and running there is a fee for registering Perfect Sudoku software. The payment can be done via Stormpay.
Cheers!
wew
Have you stopped the daily killer sudoku?
No, I haven’t! 🙂 I only missed a day – it’s been very busy for me and also I thought that the Samurai X should keep you busy for a while.
Anyway, in a few minutes you will see a new Killer Sudoku puzzle!
Cheers
Must have missed some instructions. Could you tell me what the “diagonal variation” of the killer sudoku is?
Opps, instructions. I definitely do need to write some sort of a manual/help/instructions, but where do I find time? 🙂
Anyway, “diagonal” Sudokus, aka Sudoku “X” are different from regulars because the diagonals (marked as light-grey lines across the puzzle) MUST contain one occurrence of each of the numbers 1-9. Just like any other row, column or “nonet”.
So, it’s an additional constraint. I think you should start off solving this puzzle just like any other Killer and then at later stages keep in mind that some numbers can/can’t go on the diagonals because of this constraint.
Hope this helps :).
thanks !!! It helped. Solved today’s killer, but I’m still fighting with 3 “normal” killers. (27, 28 and 30 sept)…. driving me craaaaazyyy
LOL
I’ve managed to do all the killers so far published except the one for 27th September. Any chance of an explanation of the logical moves made to solve it – I’m stumped and I don’t think I’m the only one judging by some comments on http://www.sudoku.com message boards!
Liked the Killer Diagonal today – the diagonals helped to finish it.
Thanks goodness – I was going mad with the diagonal variation – I hadn’t even though that the diagonal lines were significant in any way. LOL – another ‘senior moment’.
Right ! I am happy and eager to purchase – where when can i download
Will killer and killer x be included ?
Wow – today’s was a toughie! Got there in the end by drawing on some extra cages in a coloured pen which I think may be what you mean by ‘cage splitting’.
Cathy, I’m glad you solved it :). I hope other people did too… I don’t want to spoil the fun for people who haven’t gone thru the puzzle yet, but once you see how simple the technique is, it will be much easier to solve other puzzles too.
Hiya all, solved today’s puzzle too. You’re right, Cathy. It sure was a tough one. By the way, I finally finished the killer of 28/09. Just one question: Is it possible to change the position of the 2’s and 3’s in colums 7&8, rows 2&9?
Cindy, you will be surprised how easy it is to solve today’s puzzle with “cage splitting” technique that I will explain tomorrow.
Regarding the puzzle 28/09, it would have been possible to change the position of the cells you’re indicating except that this was a DIAGONAL Killer Sudoku! It was indicated back then that it has two solutions – one diagonal and one non-diagonal. If you exchange 2’s and 3’s your bottomleft-upperright diagonal would have number 3 twice in it.
Cheers!
I didn’t realize the puzzle 28/09 was diagonal. On the copy I downloaded weren’t any diagonal lines…. lol
I have only just discovered killer sudoku’s, and this was great! I admit, it took me 5 hours to solve (when I should have been sleeping), and had to learn a couple of new strategies to make it happen. I’m keen to find out what this “cage splitting” is.
Cindy, back then I didn’t print the diagonal lines, I only stated that it’s a diagonal. Sorry. 🙁
like others have solved all your puzzles (eventually) but do not think the 27/09 killer is solveable by logic. would be glad to be proved wrong.
Same here, solved them all except for the 27/09 killer… anyone???
good!
Although you solved it trial and error is not logic is it.it is guessing. anyway how about grading your killer sudoku.
es para uso personal
Any more about the cage splitting technique? I use the innies and outies technique which quite often gives me the split for a cage – is this the same thing?
Graham, innies and outies are not the same thing as cage splitting. Look at the FIRST step here: http://www.djapedjape.com/?p=53
I found that two non-touching cells that belong to two different cages must have the sum of 11 which can only be 2+9, 3+8, 4+7 or 5+6. Then I compared those possibilities against the existing possibilities (which are coming from their cage sums) for those 2 cells and found that the only solution is 2+9.
Hope you see the difference between innies/outies and this.
Thanks for clearing that up. I HAD been using that particular technique but wasn’t sure of the correct terminology.
Many thanks for these great puzzles – keeps me from having ‘senior mometns’
Can anyone give me a pointer to start 28/9 – I only have r1c1 and r9c9!!! It’s making me feel very unintelligent.
I would like to get a killer sudoku solver for free and for my personal use. Thank you.
Hi Jesus,
A new version of Perfect Sudoku will be available for download in a few days. Please come back and check this page.
Thanx!
It’s OK I’ve done it now. Phew!
How do I get to archive in your website? I need the September solutions and it keeps directing me to October ones. If I press on archive – September link all it shows me are the articles, not the actual puzzles and solutions.
Thanks
Olga
Olga, the puzzle archive contains only the puzzles for the previous week. We can’t keep all the previous puzzles – it wouldn’t be profitable for us.
The monthly archives contain posts for the selected period. Puzzles are not included there.
If you’re puzzle hungry and need more – just keep coming every day and you’ll find two brand new puzzles!
If you need a solution to specific puzzle, let me know which one and I’ll make it available for a few days in the puzzles archive.
I really enjoy the Killer published here everyday so “keep ’em coming”. However I find with some of the puzzles that I get so far, say a third of the numbers solved, and then I come to a grinding halt. What techniques am I missing? Should I be looking for unique combinations or do I need to start trial and error (which I dislike). For example the 13/10 puzzle. I managed 30 numbers and then couldn’t get any further.
Phyllis, I don’t think that any of the puzzles except September 27 need trial and error to be solved. You should always consider the cage sums and perhaps on some of the more difficult puzzles you should try the cage splitting technique. Check the solving tips section. Also, don’t forget to use the standard Sudoku solving techniques, such as naked/hidden pairs etc.
Now that I have a difficulty rating system implemented it will be more clear what techniques are needed to solve each puzzle.
Hi Djape,
Is it possible to send me the latest version of perfect sudoku? I seem to be having difficulty downloading the file. The download just doesn’t start. May be company policy to filter these things, but I don’t have internet access at home. Not yet that is!! :o(
Thanks a million,
John Smits,
Antwerp, Belgium.
Thanks for the response. I have been using the complex innies/outies technique for a while. I must be missing some of the standard sudoku techniques. Are they on this site?
Hi John, new version of Perfect Sudoku will be available for download in a couple of days. The download of old version has been removed because the new version is coming.
Check the download page in a couple of days!
Hi I’m an addicted ex-pat living in Japan and would like to comment about the Oct 13 killer puzzle. I believe it’s impossible for the following reasons;
The centre nonet adds up to 53 therefore the centre right nonet bottom left must be 8. If this is 8 the centre right nonet adds up to 61. Therefore the centre bottom and right bottom must add up to 16 which can only be made with 9+7. It is then impossible to make the 13 required in this nonet because 9,8and 7 have been used.
Mike, you have an error in your reasoning. It is this sentence: “Therefore the centre bottom and right bottom must add up to 16 which can only be made with 9+7.”. R6C[8-9] must add up to 12, not 16! How? 45-(4+8+13+8)=45-33=12. The rest of that “funny” cage shaped like an inverted letter “C” must add up to 16. I think you mixed up the calculation for innies and outies :).
If in doubt – check the solutions section in the archive – it proves that there is a solution! 🙂
Where is the grade of the puzzle shown?
Oops, thanx for asking that question – I put a comment on the Daily Killer page. Today’s puzzle is rated “COOL”.
Glad I found this site as its very difficult to find any killer sudoku online apart from timesonline and the images are very blurry.
It would be handy if you could add a number to each puzzle rather than by date!
Hi (again)
Whoops!
Great site.
Mike Japan
did you change the way you post daily sudoku. i used to be able to view today i cant
Cindy, I hope you managed to get today’s puzzle. You must use your browser to open the “Daily Killer” page and then click on the image to download it.
I had to change it to work this way because we had some fraudulent activity where people were downloading images without visiting the site.
Please let me know if it works Ok.