Iam happy to announce the arrival of a new and more challenging variation of sudoku. That of Killer Samurai. On this site you will know about samurai puzzles and killer sudoku puzzles. However one of this sites visitors, Melvyn Lawes has combined the two to create Killer Samurai.
Killer Samurai 7 - Download
Killer Samurai 6 - Download
Killer Samurai 5 - Download
Killer Samurai 4 - Download
Killer Samurai 3 - Download
Killer Samurai 2 - Download
Killer Samurai 1 - Download
NEW - *** Do you like Killer Samurai? If so visit the new Killer Samurai Site dedicated to this new and advance form of Sudoku at www.killer-samurai.com. New Killer Samurai Sudoku Puzzles will now no longer appear on this site.
This site is the first and at the moment the only website to feature Killer Samurai. Melvyn has kindly offered to try and produce a new Killer Samurai each week and has given me permission to reproduce it on this site. I suggest that you should bookmark this site and come back in one weeks time for the next Killer Samurai Puzzle. Please enjoy and if your want to, leave comments at the footer of this page. Once again I would like to thank Melvyn Lawes for this contribution.
This page has been superceded with an updated version and you can now find new Killer Samurai Sudoku puzzles in colour and black and white here. Also more information about Killer Samurai in the Media can be found here
Publishers - Are you interested in publishing these unique Killer Samurai Sudoku Puzzle on a weekly or one off bases? If so please contact me with the details of your magazine/publication.
Comment 1 by Becca. Made on the 16th Sep 2005.
Attempted this and spotted an error - top left square of bottom right grid - i.e. containing 11 (yellow), 8 (blue) and 16 (purple). If you add these they come to 35 meaning the remaining cell needs to be a 10! Looked at solution - the 11 should actually be 12.
Comment 2 by Alan Shaw. Made on the 16th Sep 2005.
You are quite right. Thanks for pointing this out. I have now fixed this issue.
Comment 3 by Daniel (site owner). Made on the 16th Sep 2005.
Daniel - I believe there is another error - middle square of top-left hand grid. The three purple cells along the bottom line in your solution add up to 11 not 12.
Comment 4 by Alan Shaw. Made on the 16th Sep 2005.
I apologise to you and Alan Shaw for the two mistakes in the Killer Samurai. I had spotted one mistake today, thanks for spotting the second.
Comment 5 by Melvyn P. Lawes. Made on the 16th Sep 2005.
I would be curious to know if Alan Shaw actually completed the killer samurai, and if so, how long it took him.
Comment 6 by Melvyn P. Lawes. Made on the 16th Sep 2005.
I may be doing something wrong I got two solutions to this puzzle. Should that be possible? From the solutions posted switch the 3 and 9 's in the bottom right 9x9 (first and last rows).
Comment 7 by Becca. Made on the 16th Sep 2005.
Becca is correct - you CAN switch the 3s and 9s mentioned. However, that's not the end of it. There are several other areas where there are alternative solutions. In order to illustrate this I have named the columns A-U and the rows 1-21. (1) The 4's and 5's can be either way round in P1/Q1 and P7/Q7; (2) The 8's and 9's can be either way round in S15/T15 and S20/T20; (3) The 6's and 7's can be either way round in C16/C17 and I16/I17; (4) Lastly, and slightly more complicatedly(!) A20/A21 must be 7 & 9, D20/D21 must be 4 & 7, G20/G21 must be 4 & 9 - each of these pairs depends on the other 2 but there are no other clues to help you solve one of them. Pity. I have to say I still liked this puzzle and in particular liked the use of colour rather than the dotted lines as normally used in the Killer version. Look forward to seeing more of these.
Comment 8 by Alan Shaw. Made on the 19th Sep 2005.
I agree with Alan. This puzzle was an awesome distraction from work and I loved the color. Thanx bunches!!
Comment 9 by Becca. Made on the 19th Sep 2005.
Hi Daniel/Melvyn - first of all many thanks for posting the second Killer Sumarai which was good fun. I reckon I have spotted one tiny "error" insofar as the 1s and 2s in cells E4/E5 and H4/H5 can be inter-changed. Apart from that - great puzzle. Melvyn - I know you are interested in time taken - I reckon I completed it in about 1 hour 45 minutes in total - although this was over the course of 3 separate sessions of 45 mins; 45 mins and 15 mins. Hope this is useful info. To give you an idea of my skill level I did today's Times Killer Sudoku in 15 mins (paper stated 22 mins as target). Again I look forward to seeing more of these particular variations - although I don't generally have 1 hr 45 mins to spare most days!!
Comment 10 by Alan Shaw. Made on the 22nd Sep 2005.
I finally finished the second killer sumarai and it took me about 3 hours (but I am generally slow at these puzzles). I found another "error" in the top left 9x9. My two solutions for the second and third row are:
I can't wait for the next one, thanx again!
Comment 11 by Becca. Made on the 22nd Sep 2005.
Hi there! I love sudoku's and am getting v.good at the killer ones except that I somehow find them easier than the 'fiendish' sudoku's. Anyway, I would love to try the samurai sudoku. I understand that the coloured squares are the same as the dotted lines that enclose the squares to sum. I am not sure if there is any significance to the sum number being put in any box other than the top left. Am I making sense? Can you tell me if there is something I am missing in the rules for this one.
Many thanks! It's great fun!
Comment 12 by suzan. Made on the 23rd Sep 2005.
Message for suzan - the specific box in which the number for a range appears has absolutely no significance. You might also want to note that within a range the same number CAN be repeated - so long as the normal Sudoku rules re. rows, columns and 3x3 boxes are observed. Hope this makes sense.
Comment 13 by Alan Shaw. Made on the 23rd Sep 2005.
quillo.. se te va la pinza tela marinera...
Comment 14 by alvarito. Made on the 29th Sep 2005.
Hi there. I love killer samurai sudoku! ive been unwell for the last 2 weeks so to consume time ive been doing the two puzzles above but now iv completed them! they are ace! is there going to be a third?
Comment 15 by Hannah Carey. Made on the 02nd Oct 2005.
could you possiby make these print friendy? i havent been able to print these and understand them :(
Comment 16 by Leah. Made on the 03rd Oct 2005.
Aces! Thank you! :D
Comment 17 by Hannah Carey. Made on the 04th Oct 2005.
when you download the third one in the bottom right quadrant there is an error with labelling and colouring with 2 squares marked 13 and two marked 10.
Comment 18 by Hannah Carey. Made on the 04th Oct 2005.
opps! Thats my fault. Ive corrected the problem. Thanks for pointing this out. Daniel
Comment 19 by Daniel (Site Owner). Made on the 04th Oct 2005.
On the third one, in the bottom right grid, a yellow group on the bottom left quadrant is marked 15, it should be 18... There might be more errors, because the sum of all the numbers isn't 1845 (41 quadrants, 45 "points" each).
Comment 20 by Lady Madonna. Made on the 05th Oct 2005.
Ack! I just spent a long time on KS#1 and then realized that you have all sorts of errors still on it. I wish I'd read the comments before I started.
If you are going to post these, at least get them so they are solvable and don't make it so you have multiple solutions! A computer program should be able to verify the solvability and the unique solution...
I love the concept but until you get them to a point where they are posted correctly, they are more frustrating than fun!
As has been noted before KS#1 still has problems. In the upper left quadrant, in the purple region in the center square (supposedly with a total of 12), the numbers shown in the solution 1,3,7 only add up to 11! There may still be more, but I didn't bother going any further.
Comment 21 by Blaine. Made on the 05th Oct 2005.
On the third one, in the bottom right grid, a yellow group on the bottom left quadrant is marked 15, it should be 18... There might be more errors, because the sum of all the numbers isn't 1845 (41 quadrants, 45 "points" each).
Comment 22 by Lady Madonna. Made on the 05th Oct 2005.
Sorry for the repeated post...
I just finished the third Killer Samurai and found no more errors. I would like to point, though, that there are multiple solutions in several places in both #1 and #3.
And @Blaine, don't worry, the only mistake in #1 was the one pointed in the fourth comment that you already noticed. Killer #2 is completely right and I already commented the only error I found in #3.
Comment 23 by Lady Madonna. Made on the 05th Oct 2005.
I have now fixed ALL the errors on puzzle 1 and 3 that were pointed out. Thanks to all those who found and posted the errors onto this page.
Iam sorry for any trouble Ive caused and I hope you have had found finding the faults an interesting and enjoyable challenge.
Once again Ill say that the puzzles are now all fixed for those who want to try them again. However it is possible that they may have multiple solutions.
Iam sorry ive not been able to make the updates earlier but I run this site as a hobby and have been very busy recently and unable to make the updates sooner.
Enjoy Killer Samurai!
Comment 24 by Daniel (Site Owner). Made on the 05th Oct 2005.
I like the concept of the Killer Samurai - you are indeed the first to attempt it, and for that, you get a lot of credit. What we need now is a computer algorithm to create them on request, so that they are all logically solvable. I have created my own variant, as well (it's a multi-puzzle variant using numbers from one puzzle as clues in the next), and I have also made errors that needed correcting, so I empathise for that regard...I'm simply happy to have a new variant to play with. =)
Comment 25 by Cyclone. Made on the 07th Oct 2005.
Ola a todos.
Esto simplemente es impresionante, llevo dos dias matandome la cabeza, estos es de locura el dia que lo solucione estaré muy feliz.
Comment 26 by Santiago Caicedo. Made on the 08th Oct 2005.
Killer Samurai - great idea! Any chance of also publishing grids in black and white? I find the colour very off putting and intend to convert to black and white myself, but it would be nice if they could be published like that. (It would be just as quick for the creater to design them in b&w, but it'll take me HOURS to re do it! :o) )
Comment 27 by Vicky Sutherland. Made on the 10th Oct 2005.
Hello, very nice puzzles indeed !
In the first problem, bottom left square of the bottom roght grid : the 12 should be 7.
Comment 28 by Stephane. Made on the 12th Oct 2005.
I think you have made a mistake. The 3 purple squares do add up to 12 not 7.
Comment 29 by Daniel (Site Owner). Made on the 12th Oct 2005.
Finished the three of them.
Looking forward to getting some more killer samurai.
Congratulations for this page.
Comment 30 by pablo domi. Made on the 25th Oct 2005.
These are fabulous. One request: I can't tell 3 from 9 much of the time in the second and third puzzles. I can read the numbers perfectly in the first. Would you change the font?
Comment 31 by Anna. Made on the 26th Oct 2005.
Awesome, but I really do need to get some sleep...
Comment 32 by Vicky. Made on the 26th Oct 2005.
Well over 7 days since killer samurai 3 and still no 4th one. Are we going to get one a week as it says on the web site
Comment 33 by Ron martin. Made on the 27th Oct 2005.
Wot is going on??????????? We want MORE!!!!!!!!!!!!!!!!!!!!!! More! More! More! You cant just addict me and then leave me hanging!!!!!!!!! No fair! Im on my knees - begging - more killers - please all other sudokus have been ruined for me!!
My most grateful thanks!
Comment 34 by phoebe. Made on the 28th Oct 2005.
On KS#1 bottom right sudoku, middle-right box, in the blue box the sum should be 11 instead of 19, printed it today.
Love the idea :D
Comment 35 by Buster. Made on the 28th Oct 2005.
I was taking a breather after so much criticism and hate-mail about the Killer Samurais. But now there seems to be more positive feedback, so yes I will endeavour to generate KS no. 4 this coming week. But I must stress that I compile puzzles as a hobby, I am by no means a professional compiler, so there may well be more than one solution and yes I make mistakes as well.
Comment 36 by melvyn Lawes. Made on the 28th Oct 2005.
I think you may be mistaken. If you look carefully the blue box you are reffering to consists of 4 suqares and not 2. Therefore it does total 19 and not 11. The puzzle is correct.
Comment 37 by Daniel (Site Owner). Made on the 28th Oct 2005.
I apologise profusely, you are correct, I must be colourblind, having a moment of stupidity.
After that stupid post I completed it :)
I find it amazing how you put these together, well done :D
Comment 38 by Buster. Made on the 29th Oct 2005.
Hello Sudoku lovers
You will be pleased to know that Killer Samurai No. 4 is now with Daniel and will be on this site very soon.
Comment 39 by melvyn lawes. Made on the 02nd Nov 2005.
He hecho los tres y no encuentro ningúnerror, bueno lo de las posibilidades pareadas pero te salen, con mucha paciencia y sin prisas....¡son la leche, me encantan!
Comment 40 by Ana Quintero. Made on the 03rd Nov 2005.
Great Job On KS#4, I completed it, so unless I went completely wrong, there are no mistakes
Comment 41 by Buster. Made on the 03rd Nov 2005.
Still a problem with KS#3. Purple 7 total in top left quadrant (position column 6/7 row 5/6) solution is given as 5+1+1. This is clearly wrong as numbers cannot be duplicated in boxed segments.
Comment 42 by Lyn. Made on the 04th Nov 2005.
And still a problem with KS#1. Purple 9 in bottom right quadrant (position column 8/9 row 3/4) solution is given as 4+4+1. Clearly wrong as numbers cannot be duplicated in boxed segments. Am I missing something or are the rules different for this type of puzzle?????
Comment 43 by Lyn. Made on the 04th Nov 2005.
I think you may be in error. It is incorrect to assume that a number may not be repeated in a box total. There may be repeated numbers as long as they do not break the standard Sudoku Rules. So if one of the boxes is in a different quadrant to the other squares it is possible that it has the same number as another square in the same total.
Comment 44 by Daniel (Site Owner). Made on the 04th Nov 2005.
Obviously some clarification required here. According to the rules accompanying the killer su doku puzzles in The Times 'within each dotted-line "shape" a digit CANNOT be repeated'.
Comment 45 by Lyn. Made on the 04th Nov 2005.
Hello Lyn. I can see why you are finding this confusing. But it is important to note that the Times did not invent Killer Sudoku. In their book they may have specified an extra rule stating that numbers can not be repeated in any total area. However this is extra and not part of 'normal' killer Sudoku rules.
The Rules for Killer Sudoku are as followed:
1) Follow the normal rules of Sudoku. i.e. Numbers 1 to 9 in each row, column and 3x3 box
2) Numbers in total areas must add up to the total of that area.
They are the simple rules of Killer Sudoku. The Killer Samurai Puzzles and other Killer Sudoku puzzles follow these rules.
There is nothing to say that you cannot have the same number repeated in a total area.
However this only happens when you have a 'dog leafed' total area where it crosses the boundary into a second 3x3 area.
Comment 46 by Daniel (Site Owner). Made on the 04th Nov 2005.
Think you are just bending the rules to justify the errors in your puzzles. Like to know where you got the 'normal' killer su doku rules from because of course The Times must be wrong!!!!! Think I'll stick to sites that have a bit more humility in future.
Comment 47 by Lyn. Made on the 05th Nov 2005.
Think I'm with Lyn. The killer sudoku solver supplied by the Funchashi Private Study School in Aichi, Japan also says you can't duplicate a number in an area surrounded by a dotted line.
Comment 48 by Toby. Made on the 05th Nov 2005.
Iam sorry you feel that way. I see no reason why a number cannot be repeated in a total area as long as it dose not break the normal rules of sudoku.
Killer Sudoku puzzles are just like normal sudoku puzzles except the total areas must equal the total for that area.
However it is also fine for other producers of Killer Sudoku puzzle to add extra rules. But in my opinion that just unneccessarily complicates them.
But for clarification. on this site the killer sudoku and Killer Samurai puzzles are allowed repeat numbers in total areas as long as they do not break any of the normal Sudoku Rules.
Comment 49 by Daniel (Site Owner). Made on the 05th Nov 2005.
Great sudoku´s buy I have a lot of trouble printing them because my printer is b/W and I can´t tell the difference between certain colours. Any ideas for getting arround the problem. A colour printer is no option (I print them at work)
Comment 50 by ghalf. Made on the 05th Nov 2005.
hello ¡¡ first of all tx for this killer, please give us more, I start the 1 and I found an error, in the top left sudoku in R6 456 are in violet adding 12, I think the correct addition is 11.
Comment 51 by Mercedes. Made on the 13th Nov 2005.
I dont quite understand. I assume you are referring to KS1. The violet area does add up to 11 and in the solution the numbers are: 317 which do add up to 11. So I dont quite understand what you are saying?
Comment 52 by Daniel (Site Owner). Made on the 13th Nov 2005.
Killer Samurai number 5 is now with Daniel and will hopefully be added to this site very soon.
Comment 53 by melvyn lawes. Made on the 14th Nov 2005.
Killer Samurai 5 is now uploaded and ready to be solved. Thanks Melvyn!
Comment 54 by Daniel (Site Owner). Made on the 15th Nov 2005.
Hot on the heels of killer samurai no.5.
killer samurai no.6 is now with Daniel. So how are you all finding the killer samurais, too easy, too hard or about right. I would be interested to hear how long it takes you all to solve them.
Comment 55 by melvyn lawes. Made on the 16th Nov 2005.
Killer Samurai 6 is ready for download.
Hope you all enjoy.
Comment 56 by Daniel (Site Owner). Made on the 16th Nov 2005.
heya, just to say thanx for the new puzzles, ive become addicted! normal killer just doesnt do it for me anymore. please keep them coming xxx
Comment 57 by abi. Made on the 17th Nov 2005.
Love this new puzzle. Thought I should point out though that puzzle number two has a couple of 'boxes' of the same colour with two different numbers in them... (e.g. 9 and 7 on the middle row of the middle row of the top left 9 square) - not quite sure what this means...?
Comment 58 by Blue Jamie. Made on the 18th Nov 2005.
Congratulations on the fantastic killer samurai! Other sudoku pale into insignificance compared to them....please keep them coming.
This must be the definitive way to delay the onset of Alzheimers!!
Comment 59 by Rosy. Made on the 20th Nov 2005.
Fantastic. Thanks so much for these. They're just sensational and I can't get enough of them.
By the way I'm in Japan and the consensus among people I've asked here is that cages can have the sum number in them as long as they don't violate normal sudoku rules. The Times can do what they like but I like the extra challenge of "cunning cages".
A quick suggestion: it would be easier for those of us with Black and White printers if the value numbers of the cages were always printed in the top left cell.
Comment 60 by David. Made on the 20th Nov 2005.
Aaaarrgh...!! server error: can't d/l nor even see KS#7!! please fix it soon, it's become an addiction. Thanx n congratulations to malvyn/daniel, you rock pals. In the meantime, I've discovered your 16x16 wich I didn't seen before... great !! as far as I know, by an article published in spain, that Maki Kaji guy (from Nikoli) is editing 25x25 grids (not "killer"), can't hardly wait to pick up one.
As for the "cunning cages" point, just say that the only killer editor here in spain (El Mundo) has always made clear about the classic sudoku rules (numbers CAN be duplicated).
For the b/w printer users (as myself), what I do is repass it with a fluorescent pen (it takes me 2mn.), wich largely acceptable results.
Melvyn: I find the level of your samurais is quite perfect, at less it's about just the right one for me, but I think you could prepare a real tricky one for a soon future (just a wish, you make a wonderful work).
Comment 61 by acab. Made on the 27th Nov 2005.
Hello Acab. - The images and downloads on this site are hosted on another (cheaper) server which is considerable less relaiable. Iam trying hard to work something out. But its not easy. The site should be working fully shortly.
For thoses who are interested a new Killer Samurai Site is currently being produced which will be dedicated to Killer Samurai. Check back soon when we launch it.
Regards, Daniel Mitchell
Comment 62 by Daniel (Site Owner). Made on the 27th Nov 2005.
I wanted to try this seemingly fabulous Killer Samurai Sudokus, but my computer doesn’t like the .doc-files. Is there any other possibility to get these Killer Samurais, maybe as a pdf-file?
Comment 63 by Iris. Made on the 28th Nov 2005.
Hi Iris, just save the image with the mouse (right click > save as...) upon the sudoku you want to print (it's a "png" file) so you'll be able to print it from your image viewer apllication, or pasting it in an image editor (e.g. "paint") and that's it.
Comment 64 by acab. Made on the 29th Nov 2005.
Hello Iris. I apprecaite that this can be a problem. As a temporary fix you could try downloading the word documents onto another pc. However I am looking into other ways around this by converting the documents to a .pdf format. This change will be made shortly.
Comment 65 by Daniel (Site Owner). Made on the 29th Nov 2005.
I enjoy but can you make the figures a bit larger or plainer please - 9's can be 3's and vice versa on my print out Cheers
Comment 66 by joan coe. Made on the 05th Dec 2005.
I've been addicted to the Killer Samurai's for a week now, having just quit my job and having lots of time on my hands! Thank you.
I just want to say that, having read through the comments on here, it is rather upsetting to think that people are actually so petty as to complain about silly little rules and errors, when you are generously providing a service out of the goodmess of your heart. From a technical stance, I have had no problems solving the puzzles. From a personal stance, luckily I'm getting better at these, I was running out of eraser on the end of my pencil!
Comment 67 by Becky. Made on the 09th Dec 2005.
I hope you did not quit your job BECAUSE of killer samurais. Keep visiting this site and tell all your friends about killer samurais as we want as much publicity as possible.
Comment 68 by Melvyn P. Lawes. Made on the 10th Dec 2005.
Sleep easy my friend, it wasn't the fault of sudoku!
Comment 69 by Becky. Made on the 13th Dec 2005.
Hello again folks. Melvyn, I would like to suggest you to push up the difficulty level in next samurais, considering that people who has done the previous ones might have increased their skill level (thanx again for your work); I've found KS#9 too "mechanical" or "automatic" to solve -guess so has been for those wich previously did the 8 previous ... See, 2 weeks ago I wrote the level was perfect for me, but right now I feel harder-is-better, without reaching headache of course -some like djape's "IQ" level -
http://www.djape.net/sudoku/wp/?page_id=38 . I 'd profite to encourage other sudokers to take 1mn for feedback.
I've noticed that you really take care about avoiding duplicate numbers in each area -althought advertising the possibility-, I think it's a pity, because duplicating numbers increase the possibilities ("candidate numbers"), therefore the difficulty -then the fun!-, specially considering that the "common" nonets -wich define the samurai- unavoidingly reduces the difficulty (each 9x9 provides helps for the others) -althrough it seems that nobody agrees me about that two considerations.
Anyway, congratulations again from Spain to you both Daniel and Melvyn, I wish you for christmas tons of visits, to "harvest" some money out of your work !! -I'm spreading the word, too...
Comment 70 by acab. Made on the 13th Dec 2005.
In france : www.e-sudoku.fr
Comment 71 by killme. Made on the 22nd Dec 2005.
Ignore the moaners - these are great
Comment 72 by Sharon. Made on the 28th Dec 2005.
Ok...sorry if this was mentioned. But I was under the assumption that you could not use the same number within a color even if it falls into another box. For example, your solution to No. 1. Bottom right grid. Left middle and left bottom boxes. The blue 15 uses 3 numbers. And the answer is 4 7 4. How can this be?? Thanks! Love the puzzles and the colors!
Comment 73 by Amanda. Made on the 30th Dec 2005.
Hello Amanda. The repeated number in the solution is fine because it does not break any of the sudoku rules because the 4's are in different '3x3 boxes' different columns and different rows.
Iam glad you like the puzzles. More of them can be found at: www.killer-samurai.com
Comment 74 by Daniel (Site Owner_. Made on the 30th Dec 2005.
Thanks for a response, Daniel! I guess it threw me off because different websites have different rules. Per the timesonline.co.uk: "Within each dotted-line "shape", a digit CANNOT be repeated." They use dotted lines rather then colors.(just another website that I download these from.) Is there a universal rule on this or just differnt per the individual that created the puzzle? Thanks!
Comment 75 by Amanda. Made on the 30th Dec 2005.
Hello Amanda again. It can be confusing as some people say you can and other say you cant. But in my personal opinion I think that as long as it does not break any of the traditional sudoku rules then it is okay. It adds to the challenge in my opinion as you have to look out for these extra combinations.
Comment 76 by Daniel (Site Owner). Made on the 30th Dec 2005.
Thanks again Daniel! It will be a bit more challenging but I'm off to go finish it now! Thanks for all the fun!
Comment 77 by Amanda. Made on the 30th Dec 2005.
Hi. I love samarai puzzles, and killer puzzles, so this mix is great! I've got a bit of a problem getting going on the first puzzle. Could you give me a few tips please?
Comment 78 by Robert. Made on the 12th Jan 2006.
found your site. the only site bar one that does killer samurais. great!! BUT, i havn't been able to try any of your puzzles yet - because i cant even print them!! ive only got black and white printer.
any chance of making the boxes out of dotted lines instead of colours? would help alot. cheers
Comment 79 by josh. Made on the 12th Jan 2006.
I sympathise with you and the other readers who visit this site who do not possess a colour printer. The reason they are in colour is because it is such a pain to produce lots of little dotted lines, but so much easier to produce them in colour. I have taken your comments on board and will attempt to produce a `B & W ` friendly killer samurai in the near future.
Comment 80 by melvyn lawes. Made on the 13th Jan 2006.
What is Sudoku?
Sudoku is a Number Puzzle that requires no mathematical knowledge. (no adding or multiplication). It is based upon Japanese style crosswords where you are required to use logic to place numbers onto a 9x9 grid.
To solve the puzzle you must make sure that every column, row and 3x3 box contains the numbers 1 through to 9. Almost all of the puzzles can be solved using logic alone and there is no need to guess. A puzzle can take from 20 minutes to 2 hours to complete depending on its level and your experience.
For a 9x9 puzzle to have precisely one solution, the initial entries need to include at least eight of the nine digits.
The smallest number of starter clues on a sudoku puzzle is 17.
Sudoku became a world hit in 2005. When measuring its popularity in enigmatic world, it is the biggest phenomenon since Rubik's Cube in the '80s.
Some people call it newspapers saver because it boosts their sales and keeps the reader audience active. Newspapers around the world embraced it immediately because people like to solve Sudoku on a daily basis, just like crosswords.
By playing it regularly you can boost your concentration and focus, prevent or ease depression, dementia and even Alzheimer's disease according to some studies.