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Su Doku Mania Has Taken Over

The Su Doku Number Game has taken over my mind. So you get the benefit of my musings as well as a handy form and a nifty little program which helps in playing games.

Su Doku is played using a 9 by 9 group of squares. Each square is allowed to contain one of of the numbers 1 - 9. But here's the catch. Each row, column and small 3 by 3 block gets to contain each number only once.

As featured, a mostly blank playing grid is published with some of the squares already filled in. Your job, should you choose to accept it, is to fill in the rest of the squares, keeping in mind the above rules.

To get you started you can download this PDF worksheet which requires Adobe's Acrobat Reader

You can also get this handy zipped application to help in manual game solving and also automatic solving of games. (Note: Corrected file errors 5/27/2007)

Finally to really get moving go to for information and to download games.

Hint #1 - Using the handy worksheet, while entering in numbers you get from the latest game, mark out the same number from all other squares (I call these the 'possibles') on the same row, column and 3x3 block.

Hint #2 - After filling in, look for any non-entered squares which have ONLY ONE 'possible'. In this square enter this remaining 'possible' as the entered number, remembering to mark out this number from the other squares on the same row, column and 3x3 block as above.

Hint #3 - If you have exausted Hint #2 look at ALL the 'possibles' in each row, column and 3x3 block. Look for a 'possible' which is in ONLY ONE of the squares in the row, column or 3x3 block. In its square enter this 'unique possible' as the entered number, again remembering to mark out this number from the other squares on the same row, column and 3x3 block as above.

Hint #4 - If Hint #3 fails to find the rest of the numbers go back to Hint #2. Continue to go back and forth as necessary. This method (in the handy program provided) has found all the numbers in some 'very difficult' puzzles.

I had assumed that I was "re-inventing the wheel" with the hints above and so I was. Go to Sudoku Hints for these and more advanced methods. Actually their program looks prettier also.

The 'handy' program is provided in a zipped format. Create a folder (maybe named 'Sudoku' if you wish) and extract the files. Then run the 'setup'. You will now have a table for keeping track of your entries. The program even marks out the 'possibles' automatically for you. Turn off the 'Auto' mode to solve the puzzle manually. If you just want to solve puzzles then you can use the 'auto' mode and the buttons which implement Hint #2, Hint #3 and the cycling back and forth as outlined in Hint #4. This third will generally solve the entire puzzle immediately. If not it will solve up to a point where you can save the game then switch to 'manual' and use the higher level techniques outlined in "Sudoku Hints" above.

Provisions are given for saving a game and for loading previously saved games. You can save a game many times if you wish with different names as you progress through solving it.

Copyright © 2005, 2006, 2007 Bernard Carlton