[edit: Now a much easier way to make killers by Børge (see final two posts in this thread)]
[edit2: JSudoku's download site has gone. Send me a pm or email to get a copy of the install file - Ed]This thread is in response to a couple of requests about how to make killers. This post is one way - and only works for vanilla and x killers. This is a merging of what I (used to) do and two descriptions by Frank and mikejapan on djape.
http://www.djape.net/sudoku/forum/viewtopic.php?p=388#388http://www.djape.net/sudoku/forum/viewtopic.php?t=956
How to create your own killer sudoku puzzle. (Normal construction time is about 10 minutes -excluding solving time)
[edit: Feb '09. Perfect Sudoku is no longer available for download. Send me a Private Message and I'll email it.][edit 2: April '09. Just found out that you need the ".net framework" installed on your computer for PS4 to work. I can still email the install file]Step 1
First download Djape's Perfect Sudoku (It takes 20 seconds). Click on the link below [Deleted link - see above].
Step 2
Once you have downloaded PS, click here;
Generate a puzzle as shown in the following picture.
If you want an X killer, follow the instructions below.
I think an X killer is better coz you can have bigger and more interesting shaped cages
Step 3
Click on the key symbol button to get the solution
then Save the solution
(File > save [xyz.txt])
Step 4
Open another copy of Perfect Sudoku Solver
and Generator.
Step 5
Open the solution txt file from step 3
(File > open)
(this makes sure the X gets in, if not on X can skip this step)
Step 6.
click on the "design" option.
Step 7
Separate the 2 windows so the solution and the design are both visible.
Step 8
Create the cage design by using left click and drag,
Keep an eye on any cages that cross nonet boundaries to ensure that no digit repeats in a cage.
Step 9
From the solution, put the cage values in.
(Double click on a cage, put the sum in, then press enter.)
Step 10
Once you have completed the grid, click on the button with the tick "count solutions". You want it to say "unique solution"
If it says no solutions you have gone wrong so recheck all the cage sums and no repeats in a cage.
If it says multiple solution, go to step 11.
Step 11
This example says there are two solutions.
Identify the double solution as shown in the picture.
Change the vertical 13 and 4 cage into a horizontal 5 and 12 cage and you now have a unique solution PS rates as Thinker.
(divide a cage using right-click & drag)
Step 12
Once you have a Unique solution, save your work by making a code string (File > save [xyz.txt])
Step 13
open & score (options > score) your new killer using
SudokuSolver (download from software forum here).
If you don't like the score go to step 14
Step 14
To make a harder puzzle, join cages and insert the new cage value. To make an easier puzzle, split cages (left-click-drag) and insert new cage value.
NOTE:
every time you do this check number of solutions to make sure it is still unique. Step 15
Try and solve the killer. When you get stuck, split a cage that helps you the most. Eventually you will have a solvable killer.
To make a graphic of your puzzle Step 16
open puzzle in your favourite software
Step 17
Press the Windows Print Screen key
Step 18
Paste into windows Paint (start >all programs >accessories)
Step 19
in Paint, click on the "select" button, then select and cut the puzzle pic
Step 20
Paste into another Paint screen then save as xyz.PNG file
Step 21
Open xyz.PNg file using a picture editor and crop to fit the image
Step 22
Upload puzzle pic to your favourite pic host (eg ImageShack)
Step 23
use "direct link url" to post image onto the forum inside image tags [img]xyzpuzzle[/img]
Step 24
to get all the formatting for posting a pic & code string & solution onto the forum, use an existing puzzle post as a template (use the "quote" button on a previous initial puzzle post to show you all the formatting)
Please let me know if these instructions are not clear. Good luck and look forward to the results!!
Cheers
Ed