# New to Sudoku... How to make a puzzle? **URL:** \ **Category:** Factual Questions\ **Created:** [November 16, 2005, 4:26pm UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327 "2005-11-16T16:26:45Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![pletchap](https://avatars.discourse-cdn.com/v4/letter/p/8e7dd6/32.png) [@pletchap](https://boards.straightdope.com/u/pletchap)\ **Post date:** [November 16, 2005, 4:26pm UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/1 "2005-11-16T16:26:45Z")
Has anyone tried to make their own Sudoku puzzle? How is it done, and do you need a computer? Is there a trick to which numbers to keep on the puzzle as ‘starters’ and which not to? What about longer puzzles with more than 9 numbers… are they functionally any different or really any harder? Personally new to Sudoku - just now getting hooked with my wife on our morning bus/Metro commute… and it IS addictive. ---
**Author:** ![pletchap](https://avatars.discourse-cdn.com/v4/letter/p/8e7dd6/32.png) [@pletchap](https://boards.straightdope.com/u/pletchap)\ **Post date:** [November 16, 2005, 4:36pm UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/2 "2005-11-16T16:36:45Z")
> [@pletchap](#): > > Has anyone tried to make their own Sudoku puzzle? How is it done, and do you need a computer? Is there a trick to which numbers to keep on the puzzle as ‘starters’ and which not to? What about longer puzzles with more than 9 numbers… are they functionally any different or really any harder? > > Personally new to Sudoku - just now getting hooked with my wife on our morning bus/Metro commute… and it IS addictive. Sorry, newish to the forum. I believe my post belongs in Cafe Society, so please move me if necessary. ---
**Author:** ![chefjef](https://avatars.discourse-cdn.com/v4/letter/c/e480ec/32.png) [@chefjef](https://boards.straightdope.com/u/chefjef)\ **Post date:** [November 16, 2005, 6:43pm UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/3 "2005-11-16T18:43:30Z")
Yes! I have tried Sodeku - or Sudoku - however it’s spelled - and it’s quite difficult. A friend of mine said to get a legal pad and draw out a bigger grid and get a pencil to visually try out different scenarios. That’s the only hint I have thusfar unfortunately! I hope more people post - it has me really stumped. ---
**Author:** ![Dead\_Cat](https://avatars.discourse-cdn.com/v4/letter/d/9fc29f/32.png) [@Dead\_Cat](https://boards.straightdope.com/u/Dead_Cat)\ **Post date:** [November 16, 2005, 6:53pm UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/4 "2005-11-16T18:53:01Z")
[This site](http://www.sudoku.com/) has a few useful pointers. I have no idea how to make one that can be solved and has a unique solution, but I’m quite good at completing them. I wouldn’t bother trying to make your own, anyway - there are plenty out there! ---
**Author:** ![TimeWinder](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@TimeWinder](https://boards.straightdope.com/u/TimeWinder)\ **Post date:** [November 16, 2005, 7:27pm UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/5 "2005-11-16T19:27:07Z")
I asked more or less the same question a while ago, thread is [here](http://boards.straightdope.com/sdmb/showthread.php?t=342034). The answer seems to be “with a fair degree of skill” – it’s pretty easy to SOLVE them by computer (look up “constraint programming”), but generating them seems to be something of a trade secret – at least I couldn’t find anything at the algorithmic level. ---
**Author:** ![Catalyst](https://avatars.discourse-cdn.com/v4/letter/c/e47774/32.png) [@Catalyst](https://boards.straightdope.com/u/Catalyst)\ **Post date:** [November 16, 2005, 7:28pm UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/6 "2005-11-16T19:28:42Z")
[Let’s make Sudoku](http://www.pro.or.jp/~fuji/sudoku/makesudoku/sudoku01.html.en). ---
**Author:** ![chefjef](https://avatars.discourse-cdn.com/v4/letter/c/e480ec/32.png) [@chefjef](https://boards.straightdope.com/u/chefjef)\ **Post date:** [November 16, 2005, 8:00pm UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/7 "2005-11-16T20:00:41Z")
I think it’s worthy that y’all even want to take on the task of building one - after my friend was telling me all about it, I scratched that idea out. Wow could I not do it! ---
**Author:** ![pletchap](https://avatars.discourse-cdn.com/v4/letter/p/8e7dd6/32.png) [@pletchap](https://boards.straightdope.com/u/pletchap)\ **Post date:** [November 16, 2005, 8:28pm UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/8 "2005-11-16T20:28:11Z")
> [@Catalyst](#): > > [Let’s make Sudoku](http://www.pro.or.jp/~fuji/sudoku/makesudoku/sudoku01.html.en). Thanks for the link, but… have you tried this? I’m having a little trouble understanding exactly what to do for each step. Apparently this is not something I’ll be able to whip up for the wife before I go. ☹ ---
**Author:** ![InternetLegend](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/internetlegend/32/13154_2.png) [@InternetLegend](https://boards.straightdope.com/u/InternetLegend)\ **Post date:** [November 17, 2005, 1:53am UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/9 "2005-11-17T01:53:46Z")
You could try one of these generators: [http://www.opensky.ca/~jdhildeb/software/sudokugen/](http://www.opensky.ca/~jdhildeb/software/sudokugen/) [http://www.harismind.com/sudoku.html](http://www.harismind.com/sudoku.html) [http://supersudoku.com/sudoku/generator/](http://supersudoku.com/sudoku/generator/) (requires free registration) [http://sudoku.sourceforge.net/](http://sudoku.sourceforge.net/) ---
**Author:** ![Pushkin](https://avatars.discourse-cdn.com/v4/letter/p/ee59a6/32.png) [@Pushkin](https://boards.straightdope.com/u/Pushkin)\ **Post date:** [November 17, 2005, 12:54pm UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/10 "2005-11-17T12:54:29Z")
> [@TimeWinder](#): > > but generating them seems to be something of a trade secret – at least I couldn’t find anything at the algorithmic level. I thought of making up a complete grid with all the numbers in place and then deleting numbers. But then it would be time consuming to run through the grid and make sure it can be solved never mind have only one solution. ---
**Author:** ![power\_sawyer](https://avatars.discourse-cdn.com/v4/letter/p/839c29/32.png) [@power\_sawyer](https://boards.straightdope.com/u/power_sawyer)\ **Post date:** [November 17, 2005, 6:17pm UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/11 "2005-11-17T18:17:02Z")
I don’t know why anyone does those puzzles more than a couple of times. After about two times you see the pattern and they all are just fill in the blanks after that. ---
**Author:** ![Pushkin](https://avatars.discourse-cdn.com/v4/letter/p/ee59a6/32.png) [@Pushkin](https://boards.straightdope.com/u/Pushkin)\ **Post date:** [November 18, 2005, 11:03am UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/12 "2005-11-18T11:03:03Z")
> [@power sawyer](#): > > I don’t know why anyone does those puzzles more than a couple of times. > After about two times you see the pattern and they all are just fill in the blanks after that. Eh? I’m not sure what you mean exactly, what pattern are you referring to? ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [November 18, 2005, 5:16pm UTC](https://boards.straightdope.com/t/new-to-sudoku-how-to-make-a-puzzle/331327/13 "2005-11-18T17:16:08Z")
> [@power sawyer](#): > > I don’t know why anyone does those puzzles more than a couple of times. After about two times you see the pattern and they all are just fill in the blanks after that. Have you tried the “Black Belt” level puzzles published in the newspapers? The really tough ones require diagnosis to find one or two key ‘starter’ numbers. BTW There is a pdf file available on the www with a detailed rundown on the whole business. Sorry I don’t have a link but if you are the persistent type you can find it for yourself.