
Su Doku 
Su Doku is a number puzzle. It has just started appearing in The Times newspaper.
You have to fill in a supplied grid so that every column, every row and every 3x3 box contains the digits 1 to 9. Some digits are given as a starting point and from these you can work out where all the other digits should go. 
To solve the puzzle you need to keep track of which numbers are allowed to be placed in each square. You can either do this through memory  too difficult for me 
or by writing the numbers in the squares. However, The Times provides a small 9x9 grid and if you have handwriting like mine this quickly gets very messy. 
So, I've created a Java Applet where each one of the 81 squares is further divided into 9 squares. Each of these squares starts showing the 9 possible values for the containing square.
If you click on one of these small grey numbers it disappears. When only one number remains it is replaced by a large black number to show the solution for that square. 
Note: you are not given any help with the thought required in solving the puzzle! But it does help with keeping track of things. 

If you can't see anything above, you probably haven't got Sun's Java Runtime Environment. Download it from www.java.com.
The Java code built into Internet Explorer does not work. 
I have also created a more advanced application which is available for download (click link below): 
Su Doku Helper 3 
Here is a screenshot:

Selecting "automatic removal" means that when an individual square has been solved,
all other individual squares in the row, column and 3x3 square will have that number removed from their
allowed numbers. Warning  this makes the game lot easier to solve and takes some of the fun away. 
The three text fields and "add to puzzle" button are for quickly adding numbers to the puzzle,
particularly useful for inputting the initial numbers. 
The "reset" button returns the puzzle to its blank state  only use this if you have made a mistake. 
Have fun. 
Page Created: 16 November 2004
Updated: 21 November 2004 